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‘Dec. 24, 1946.
2,413,062
B. F. MIESSNER
APPARATUS FOR THE PRODUCTION OF MUSIC
Filed Nov. 1, 1941
Fs-i
C01. II CoLIII ‘Col. IV
.0571
.375
1.00
.55
‘1.00
.20
.60
1.00“
1.20
1.97
2.00
3.25
3.55
4.35
5.02
6.77
9.00
11.57
7.00
9.33
12. 00
4.18
14.44
1.4.96
8.84
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59
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2.00
3.00
5.57 -
7.17
4 Sheets-Sheet l
Dec. 24, 1946.
.
B. F. MIESSNEYR
‘
2,413,052
APPARATUS FOR THE PRODUCTION OF MUSIC
Filed Nov. 1, 1941
D
.E
03
A
BB
4 Sheets-Sheet 2
.
Dec. 24, 1946.
B. F. MIESSNER
2,413,062
APPARATUS FOR THE PRODUCTION OF MUSIC
Filed Nov. 1, 1941
4 Sheets—Sheet 3
61
INVENTOR.
Dec. 24, 1946.
B. F, MlEsSNER
2,413,062
APPARATUS FOR THE PRODUCTION OF MUSIC
Filed Nov. '1, 1941
4 Sheets-Sheet 4
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“144
INVENTOR.
Be '
BY
inEMfessner
Patented Dec. 24, 194$
2,413,062
UNITED STATES PATENT OFFICE
2,413,062
APPARATUS FOR THE PRODUCTION OF
MUSIC
Benjamin F. Miessner, Harding Township, Morris
County, N. J ., assignor to Miessner Inventions,
Inc., Harding Township, Morris County, N. J.,
a corporation of New Jersey
1
Application November 1, 1941, Serial No. 417,468
4 Claims. (01. 84-1.15)
2
This invention relates to the production of
music, and more particularly to the production of
tones of bell or chime nature, In carrying out
the invention there may be employed mechanical
vibrators, which may for example be either of
rod form or of the tubular form commonly used
for orchestral chimes; and the vibrations of these
vibrators may be translated into electric oscilla
tions and those oscillations in turn into sound.
It is an object to provide improved vibrator
means in instruments adapted for the produc
tion of such tones.
It is an object to provide improved means for
translating the vibrations of the vibrator means
into electric oscillations.
It is an object to provide improved means for
controlling the vibrations of the vibrator means
and the oscillations translated therefrom.
Such translation of course has the effect of re 10
Other and allied objects will more fully appear
moving all limitations on the volume of output
from the following description and the appended
sound, and of permitting the use of small Vibra
claims.
tors when desired. I also employ it to great ad
In the description of my invention hereinafter
vantage in controlling the harmonic structure and
set forth reference is had to the accompanying
other qualitative characteristics of the output 15 drawings, in which:
tone. While in carrying out such control it is
Figure 1 is a table showing certain relation
possible to take advantage of certain broad prin
ciples already known, their application to vi
brators of this character involves special prob
ships between the partial components of vibra
tion of vibrators which may be employed with my
lems which arise because of the nature of the 20
vibrators, their inherently inharmonic series of
partials, and other peculiarities.
One special problem arising in connection with
invention;
Figure 2 is a side view, principally in elevation
but partly in section, of one embodiment of my
invention;
'
Figure 3 is a cross~sectional view taken along
line 3—3 of Figure 2;
Figure 3a is a cross-sectional view taken along
line 3a-3a of Figure 3;
Figure 4 is a family of curves illustrating the
the production of some tones of the nature above
mentioned is the provision of a proper “hum”
tone, of lower frequency than the apparent
fundamental tone and of lower amplitude, and of
proper rate of damping relative to the rates of
manner of vibration of a vibrator such as shown
other tone components. By my invention I am
_
able to provide such a hum tone in thoroughly 30 in Figure 2;
Figure 5 is an elevational view of a slightly
regulable amplitude and damping rate.
modi?ed form of vibrator which may be em
Another special problem arising in the produc
I ployed;
tion of these tones, and particularly in the pro
Figure 6 is a crossesectional view taken along
duction of bell tones, is the provision of a sul?
ciently compact series of components which,
while containing many inharmonic intervals, will
be su?iciently characterized by harmonic or ap
proximately harmonic intervals to yield a pleas
ing tone sensation. By my invention I am able
E)
line 6——6 of Figure 2;
Figure 7 is a front elevational view of a fur
ther modi?ed form of vibrator;
Figure 8 is a view, principally in section, of an
alternative embodiment of my invention;
to achieve this result to an even more perfect de 40
Figure 9 is a vertical cross-sectional view taken
along line 9—9 of Figure 8;
gree and with much greater certainty, as well as
with far lower size and cost, than in conventional
Figure 10 is a cross-sectional view taken along
line l?—l0 of Figure 11;
These problems are typical of many which, to
Figure 11 is an enlarged top plan view of the
gether with their solutions, will be apparent from 45 translating device 6i (and a fraction of the vi
the detailed description of my invention.
brator 52) of Figure 8;
It is an object of the invention to provide im
Figure 12 is a family of curves illustrating the
proved and simpli?ed means and methods for the
manner of vibration of a vibrator such as shown
production of tones of the types described.
in Figure 8;
bell manufacture.
It is an object to produce improved tones of the 50
type described.
It is an object to provide means and ‘methods
for obtaining a series of components properly re
Figure 13 is a view similar to Figure 9 but illus
trating a modi?cation of the showing of that
?gure;
Figure 14 is a fragmentary view of the vibrator
lated to each other, in various respects, for the
of Figure 8 together with a modi?ed form of
production of such tones.
55 translating device which may be employed;
2,413,062
3
Figure 15 is a similar view illustrating a still
as I3) into which the top ends of the vibrators
Figures 17, 18 and 19 are cross-sectional views
ness, being that which appears in Figure 2. Se
cured to and depending from the rail H may be
a vertical apron It, typically of thick wood, on
are securely gripped. Each vibrator may typical
further modi?cation of the translating device;
ly be a flat strip of steel-i. e., rectangular in
Figure 15 is a vertical view, partly in elevation
cross-section though preferably with slightly
and partly in section, of the vibrator of Figure 8
with certain still further modi?ed translating Cl rounded corners, as seen in the cross-sectional
Figure 3—with its smaller dimension, or thick
devices and associated circuits; and
respectively taken along lines il—li’, i8—l§3 and
I9—l9 of Figure 16.
The vibrators with which I have particularly
illustrated my invention may generally be classed
as beams. More speci?cally, I have illustrated
them as of two types—rods ?rmly secured at one
end and tubes ?exibly suspended at one end
‘ > which the mechanico-electric translating devices,
or pick-ups, may be mounted. While any de
sired means may be employed for setting the
vibrator into vibration, I have by way of exam
ple illustrated a hammer It arranged to strike
(the other end in either event being free) , though 15 the vibrator,’ and-adapted to be propelled by some
conventional action mechanism such for example
it will be understood that no unexpressed limi
as a piano action.
tations of the vibrators to these particular forma
While there may be employed any known form
tions or manners of support is intended. The two
of translating device operating in spaced rela
types abovementioned respectively behave, vibra
tion to the vibrators (some of which for example
tionally, as a “clamped-free” beam, and as a
are shown in Patent No. 1,929,027 to me and in
“free-free” beam—the ?rst being, and the sec
Patent No. 1,906,607 to Jacobs), I have illustrated
ond not being, constrained against rotation at
herein translating devices of an electromagnetic
the supported end. The vibration of each type
type. Thus one translating device appears as 2|,
is c'omplex—i. e., contains a series of partial
comprising coil Ziiinset into the apron l6, and
components. The partial series for the two types
magnetic member IS passing horizontally
are capable of joint discussion, subject to certain
through the coil and apron and through a me
speci?c distinctions which will be pointed out.
tallic rail i‘? on the back ‘of the apron, the mag
Thus the tabular Figure 1 of the drawings shows
netic member 1 9 being adjustable horizontally
in column II the relative frequencies of vibration
and lockable in any desired position by means
for the several partials of a “clamped-free” beam.
of set screw H3 in rail H. The magnetic mem
It is proper to take it also as applying to the
ber may comprise a permanent magnet; but pref
“free-free” beam, subject to the following quali
erably its forward portion Isa will be of soft iron,
?cations: (1) that the second partial of the “free
secured to the forward end of the magnet proper.
free” beam is then very minutely higher in rela
Preferably in the carrying out of my inven
tive frequency than shown for the second partial
tion there Will be employed in association with
in the table, and (2) that the ?rst partial of the
each vibrator a second translating device placed
“free-free” beam is then not an actual vibration
at a different position longitudinally of the vibra
within the beam, but is the pendular swing of
tor. Accordingly in Figure 2 there appears a sec
the beam as a unit about its suspension, at a low
ond translating device 2|’; it may be entirely
frequency determined by the mass and center of
similar to the device 2|, and various parts of
gravity of the beam and not necessarily directly
it bear designations similar to corresponding
related to the relative frequency value shown for
parts in the device 21 but furnished with prime
the ?rst partial in the table.
_
It will of course be understood that the table
is intended simply to show the relationships be
tween the frequencies of the, partials of any one
vibrator, and is not concerned with frequency re
lationships between different vibrators. It will
further be noted that the relative frequencies
have been arbitrarily referred to that of the third
partial as unity.
Li
marks.
In determining the proper positions of the
translating devices longitudinally along the vibra
tor I take account of the peculiar way in which
the vibrator tends to vibrate. In Figure 4 this
is developed, for the several partials, in greatly
exaggerated form. The several curves herein
designated as L2, etc., represent, individually
While the use of mechanico-electro-acoustic
translation with the beam vibrators may be made to emphasize the lowest partials, so that one of
for the correspondingly numbered partials, the
‘able to go still higher in the series, for the funda
mental of the output tone. One or more partials
lower than the fundamental may then be em
ployed to create the hum tone-but, as above
effected by the presence of the weight is not
large.
Preferably the pick-up 2! will be positioned
configuration which the vibrator tends to assume
at the peaks of its vibration at those partials re
spectively (the total vibration of the vibrator be
them becomes the determinant of apparent pitch
ing of course a superposition of curves respec
of the tones, I have found that this is usually
tivelyof the forms of the several ones shown).
musically undesirable—among other reasons, be
Actually this data is presented for a vibrator
cause of the wide frequency spread between such
provided with some weight at its extremity, as
a partial and those above it. As a generality,
the third partial is usually the lowest which it is C) JU hereinafter described; but in the portion nearer
the base or ‘lug Is the change in the several curves
desirable to employ, and frequently it is desir-‘
‘ relatively'near the base of lug l3—for example,
at 1/5 to 1/6 times the length of the vibrator away
from the lug, where it will translate all partials
up to those quite high-numbered ones which have
fully apparent in connection with the descrip
nodes at about the pick-up position. The pick
tions of typical embodiments of my invention.
In Figure 2 I illustrate an embodiment of my 70 up 2i’ may be positioned relatively further from
the lug 13, for example at about .55 times the
invention employing “clamped - free” beams.
length of the vibrator therefrom. The pick-ups
Herein I! is a massive rail, preferably metallic,
may be electrically connected together-if de
to the front of which the individual vibrators
mentioned, this must be of rather limited ampli
tude.
These considerations will become more
sired, through respective potentiometers 22 and
(one of which appears as l2) are fastened
through respective lugs’ (one of which appears 75 22'-—-in such a phase relationship that the os
5
2,413,062
cillations respectively translated by the two pick
ups from the ?rst (and from the second) partial
vibration will be effectively opposed against each
other. The amplitudes of the composite ocilla
tions translated by each pick-up may be regu
lated—either by adjustment of the efficiency of
the pickups (for example, by adjustment of the
spacings of the ends of magnetic members l9
and I9’ from the Vibrator) or by the potentiome
6
is almost 2; but it is noticeably non-exact. The
frequency ratio of the second to the third partial
is 112.8; and this odd relationship militates
against the pleasantness of the use of the second
partial as a hum tone. I have observed, how
ever, that by the use of a weight of the proper
size, the frequency ratios may be changed to
those shown in column 3 of Figure l. Herein
the ratio of second- to third-partial frequency is
ters or by both—-so that either one of the ?rst 10 changed to an integral 1:3 relationship; at the
and second partials may be balanced out from
same time the otherwise inexact fourth-to-third
the combined pick-up output, and the other
relationship becomes a quite exact 2. Further,
greatly attenuated.
the useless 3.25 relationship between ?fth and
The arrangement just described is well adapted
third partials becomes 3.35 (almost exactly
for the production of a tonein which the third
10/3) and the relationship between ?fth and
partial is to form the fundamental (i. e., the
fourth just half that much (i. e., 5/3) -musically,
frequency apparently determining the pitch of
the interval of an A to a C therebelow. Among
the tone), for it will be seen from Figure 4 that
the higher partials, while the eighth loses its
the same phase of pick-up inter-connection which
integral relationship to the third, both the sev
causes an attenuation of the ?rst and second
enth and ninth take on such a nature which they
partials will, with the pick-ups at the positions
lacked in the unweighted vibrator.
mentioned, cause a reinforcement of the third
While the value of the required weight may
partial. At the same time an interdevice rein
be determined by test in any particular case in
the light of the foregoing description of the re
sults made possible, I may mention that in cases
which I believe typical I have found that a weight
of the order of 1/2 of the mass of the vibrator
has been found to give the above-described re
and in its attenuated amplitude will in many
sults, when positioned with its center of gravity
cases be of no consequence (in view of the fur
very nearly at the extremity of the vibrator.
ther fact of its extremely low'frequency). On 30
It has been known heretofore to thin the
the other hand, the adjustment may be carried
vibrator
in a region closely adjacent its base, to
beyond balancing out of the second partial, to
effect some improvement of frequency relation
ward complete balancing out of the ?rst; in this
ships over those characterizing the simple vi
way there may be introduced as much second
brator; a vibrator so thinned is shown in the de
partial as may be desired for a hum tone.
tail Figure 5. But I ?nd preferable the use of the
The embodiment of Figure 2 has so far been
weight as disclosed (or, as a permissible variation,
discussed without special reference to a weight
a joint use of weight and of slight thinning);
15 which is shown secured to the vibrator ad
there is thereby provided better control of the
jacent its free extremity. This weight may for
40 improvement of frequency ratios as well as of the
example be of the form illustrated in Figures
precise ?nal tuning of the vibrator-—beside the as
3 and 3a: a block provided with a longitudinal
surance that the proper effects on all the charac
cut liia adapting the block to fit over the thick
teristics involved will be obtained jointly. I may
ness dimension of the vibrator, and preferably
mention that when employing the weight with a
forcement will occur for some of the partials
higher than the third.
The adjustment of the oscillation amplitudes
may be made to eliminate the second partial
completely; the ?rst will be greatly attenuated,
having slightly wider cuts if?) made inwardly
from its extremities so that only a restricted cen
tral portion will be clamped in contact with the
vibrator by a set screw Hie-the latter feature
avoiding any appreciable local stiffening of the
vibrator and any likelihood of rattling between
vibrator and weight.
Very slight shifts of the
weight are useful for close ?nal tuning of the
vibrator; but the primary purpose of the weight,
and the purpose for which it is apportioned, is
the improvement of the inter-partial frequency
ratios.
It may be mentioned that it is a desirable
re?nement to make the cuts ll’lb of slightly dif
ferent depths, so that the central clamping por
,. vibrator which has been appreciably thinned ad~
jacent its base, the proper position of the weight
may shift somewhat from the free entremity to
ward the base, as illustrated in Figure 5.
I have above discussed the typical case of the
use of the third partial as the fundamental of the
output tone. While this is musically useful, there
are two factors each of which may at times mili
tate against its pleasing nature: ( 1) the nearest
hum tone therebel'ow is removed therefrom by a
3:1 ratio (assruning the ratio improvement dis
closed above) which, though harmonious, is a long
interval (musically, an octave plus a “?fth”) ; and
(2) while the third partial is a predominant part
of the tone from shortly after inception on, it
tion is slightly de-centered. It thereby is made
tends at and immediately following inception to
possible to reverse the relationship between the
be obscured to a considerable extent by higher
center of gravity of the weight and the center
components.
of its clamping to the vibrator, which may occa
Indeed, under some circumstances the pitch of
sionally be desirable for the most perfect joint
the tone seems to be consistently estimated at a
achievement of the ratio improvement above
mentioned and of precise tuning to the frequency - value which does not appear as any of the par
tials, but instead is half the frequency of .the ?fth
desired for the vibrator.
partial. I believe there are two possible explana
The frequency ratios shown in column 2 of
tions
for this: (1) that, since this value of half the
Figure l, for the unweighted beam, will be seen
frequency of the ?fth partial is almost exactly
to be characterized by an almost complete ab 70
the same (in the case of the improved ratios
sence of harmonious relationships to the third—
above described, quite exactly the same) as the
partial frequency (harmonious relationships be
difference or beat frequency between the sixth
ing expressed by the ratios of reasonably small
and ?fth partials, it is supplied, as a missing
integers to each other). ‘It is true that the fre
quency ratio of the fourth to the third partial 75 fundamental, from those two partials, by a well
understood physiological and psychological ac
2,413,062
7
tion on the part of the listener; and (2) that
while the ?fth, a prominent- partial, may estab
lish the note family (i. e., the A family, or B
8
strong amplitude of third-partial component; and
(2) the “sub-quint” frequency of the third par
tial, while useful as a hum tone ‘frequency, is fre
quent-ly considered not to be» the ideal one for a
family, or the like) to which the note belongs,
the judgment of the octave-level to which the 11 sole hum tone.
The ?rst disadvantage abovementioned may
note belongs is distorted downwardly by one oc
be’ obviated by further repositioning of at least
tave by reason of the presence of lower tone
the more outwardly of the-translating devices.
components (of which there are none below the
Thus I have shown in Figure 2 a translating de
pitch-establishing fundamentalin the case of a
vice 21"’ which may be substituted for 2|’ or
tone having only harmonious components).
2|” by the switch 23. This device Zl'” may be
In any event, I have frequently found it pleasing
relatively nearer the translating device 2l--for
and satisfying to adopted half the ?fth-partial
example at about .275 times the length of the
frequency as the tone fundamental, or apparent
pitch determinant, In this event, assigning this
a value of unity, the inter-partial frequency re
lationships (on the improved-ratio basis) become
vibrator (the device 2i being for example at
about .2 times that length) from the lug [3. Such
a positioning of the translating devices results
(assuming the adjustment of their outputs to be
for-full elimination of the second partial) in al
most perfect elimination of the ?rst partial, rather
small‘ translation from the third partial, a medi
those shown in column 4 of Figure 1. While the
fourth-partial frequency appears to be badly re
lated to the new fundamental for a ?rst overtone
(by 1.2:1, or 6:5, which is the musical interval
um degree of translation of the fourth, and an
from C to A thereblow), this is not the case in’
almost normal translation of each of the next
the production of a bell or chime tone-of which
several partials.
an important characteristic has been pointed out
The second disadvantage abovementioned-the
to be the presence of a “quint” tone at just this
frequency relationship to the fundamental. The 25 lack of a hum tone of frequency other than the
“sub-quint” (which latter has now been reduced
?fth- and sixth-partial frequencies become re
in amplitude)—may be obviated by the deriva
lated to the new fundamental in the highly de
tion of a bum tone of any desired frequency from
sirable 2 and 3 ratios. And of the lower partials,
a separate or supplementary vibrator simultane
the second and third each bear theoretically good
relationships (respectively 1:5 and 3:5) to the new 30 ously excited with the main vibrator 12. With
out intending any unexpressed limitation as to
fundamental.
the
form of the separate vibrator or as to the
To emphasize the now particularly important
manner of its excitation simultaneous with that
?fth and sixth partials, as well as to more great
of the main vibrator—both of which may obvi
ly minimize the third (which now should at most
ously be varied within wide limits—I have never
be merely .a hum tone), it is desirable to re-posi
theless shown an embodiment of what I consider
tion at least the more outwardly of the twotrans
an extremely simple and effective arrangement
lating devices, or pick-ups. Typically it may be
for
the stated purpose. It comprises the secur
brought nearer to the base of the vibrator; and
ing to the main vibrator l2 (preferably very near
accordingly I have shown in Figure 2 a translat
ing device 2!” which may be substituted for the , the base or lug I3, so as to have a negligible in
?uence on the vibrational characteristics of the
device 2|’ by means of a switch 23. The device
main vibrator) of one end of a supplementary
2!" has been shown by way of example as posi
vibrator, which itself may for example be a rod
tioned at about .4 times the length of the vibrator
32 bent (closely adjacent the secured end just
from the base. From Figure 4, and it being borne
mentioned)
to extend upwardly in front of lug I3.
in mind that the translating devices'are electrical
The supplementary vibrator 32 will of course re
ly connected for opposition of oscillationstrans
ceive an impulse excitation through the main vi
lated from l-o-werepartial vibration, it? may be‘
brator l2 whenever the latter is subjected to its
seen that‘ opposition’ will occur for-the ?rst, sec
impulse excitation, as by hammer [4.
ond and third partials simultaneously, while‘aid
An apron 35, analogous to IE above described,
50
ing will occur for the fourth, ?fth and3sixth
may extend for a short distance upwardly from
which latter are to be prominent ingredients of»
rail II to hold a translating device 3i (similar
the tone.
to 21) in operative relationship to the supple
A typical adjustment of the relative‘ outputs
mentary vibrator 32. The output of this transe
from the pick-upg? and 2 l "’ may be the adjuste
lating device, regulated if desired not only by
ment which fully balances out the second partial;
the spacing of its magnetic member from 32 but
This adjustment will be attended by some net
also by a potentiometer 30, will of course be con
translation-from first partial; but this is so par
nected with the joint output of the translating
ticularly low in- frequency relative‘ to the new
devices previously described. Obviously the regu
fundamental, that in many cases the mere in
herent frequency-transmission characteristic of 60 lation of the output of the device or pick-up 3|
provides a complete regulation of the amplitude *
the system to which the oscillations aresupplied
of the added hum tone relative to that of other
may be suf?cient to insure its absence from the
tone components. Furthermore, the possible in
output tone. The mentioned adjustment will
?nitesimal postponement of influence of the ex
also be attended by some net translation o-f-third ‘
partial, which will be utilizedand relied‘on-to '“ citing means on the supplementary vibrator (re
sulting from the indirectness of transmission of
form the hum tone. It will berappreciated that
the exciting-means action) quite parallels the
this hum tone will bea “sub-quinti-’—that~ is,
slow development of the hum tone in the bestv
.of a frequency an octave below thef‘quin ” above
bells‘.
mentioned as formed by the fourth partial.’
The partial of the supplementary vibrator (it
While a tone-producing system so arranged and
self a “clamped-free” beam) which is preferably
adjusted is very ,satisfactoryin. many instances,
relied on as the hum tone is the ?rst partial.
two possible disadvantagesfor certain purposes:
This has the joint advantages (1) of rendering
may be mentioned: (1) the. adjustment which:
eliminates or sufficiently. minimizes the . second-'
partiaL component . may. leave ' an undesirably
the-supplementary vibrator of minimum length "
75 forthe thicknessemployed (which thickness it;
2,413,062
self may be made very'small, so that the whole
mass is in turn very small) and (2) of causing
the ?rst overtone of the supplementary vibrator
to fall at a relatively high frequency (i. e., at least
of the order of 6.25 times the supplementary
vibrator-?rst-partial frequency), which will usu
ally occur in the range of several times the fre
quency being used as the fundamental of the out
put tone developed (except for the contributions
of the supplementary vibrator) from the main vi
brator.
,
And I may point out the preferred thinning of
the supplementary vibrator near its base (for ex
ample, just above the bend abovementioned) su?i~
~ ciently so that its second-partial frequency be
comes harmoniously related to the frequency be
ingrelied on as the fundamental from the main
vibrator. Probably the preferred hum tone (and
therefore the ?rst-partial frequency of the sup
10
for both supplementary vibrators.
Differential
adjustments of the translations from the two sup
plementary vibrators may be made by bending of
these vibrators; and this expedient may if desired
be relied on for all adjustment of the translations
from these vibrators, dispensing with the need
for adjustability of the magnetic members in the
translating device 3 I.
Figure 2 illustrates a further expedient for the
control of the partial-frequency components from
the main vibrato-r which may be employed when
desired. This is the selective damping of the vi
brator, to cause the rapid decay of certain com
ponents without appreciable effect on others.
Such selective damping may be effected by plac
ing on the vibrator, at a point which is apprecia
bly non-nodal for the components to be affected
_ but is substantially nodal for those which are to
remain substantially unaffected, a damping struc
plementary vibrator) is an octave below (i. e., 14; 20 ture wholly carried by the vibrator. Such a struc
times) that fundamental frequency. If then the
ture has been shown at 2'! in Figure 2. As seen
second-partial frequency of the supplementary vi
in this figure (aided by Figure 6) , it may for ex
brator 32 be made 8 times its ?rst-partial fre
ample comprise a piece 28 of damping material
quency (readily done by thinning as abovemen
(for example, of the synthetic rubber “neoprene”
tioned), it will provide a component of 4 times
which is characterized by appreciable viscosity,
the frequency assigned as the fundamental of
or of the still more viscous and less resilient
the note being produced—thereby supplying a
“Visccloid”) bent into the form of a U about the
very useful overtone carrying the series of con
vibrator, and a member 29 surrounding the piece
secutive harmonic overtones onward from the 2
28 and clamping it in place. For the illustrated
times and 3-times already provided (by the main 30 vibrator the member 29 may for example com
vibrator) to include the 4-times. On the other
prise a generally U-shaped spring, preferably
hand, for example, the second-partial frequency
formed with inward bulges 29a a short distance
of the supplementary vibrator 32 may be made 7
from the respective open ends of the U-these
times its ?rst-partial frequency, so that it will
bulges
performing the clamping function, and
provide a component of exactly 31/2 times the fre
they and the inside central portion of the mem
quency assigned as the note fundamental; a lim
ber 29 forming three regions of contact of that
ited development of such “half-integer” com
member with the piece 28. The damping struc
ponents has been sometimes thought desirable in
ture has a length (i. e., dimension longitudinally
the creation of .the best bell or chime‘ tones.vv
of the vibrator) preferably of quite srna11 order-v
In terms of the fundamental produced as above it) its function not being to impede the vibratory
described by the main vibrator, the total partial
deformation of the vibrator within that length,
series in the output tone (up to the frequency of
but rather to take advantage of the inertia of the
the tenth partial of the main vibrator) becomes
mass of its elements. Because of this inertia,
.5,* .6, 1, 1.2, 2, 3, 3.5 or 4,* 4.18, 5.57, 7.17, 8.84
the asterisk denoting derivation from the sup
plementary vibrator. This series is characterized
small though it be, the damping structure tends
" not to move vibratorily; and the vibratory forces '
transmitted to it from the vibrator, forced to pass
through the piece 28 of damping material, cause
by (l) a most desirable hum tone of .5, (2) a use
an energy dissipation in the latter.
ful further hum tone of the “sub-quint” fre
Those forces, and hence that dissipation, are
quency of .6, (3) a perfect series-1, '2, 3, and, if oro obviously supplied only at the frequencies of those
desired, 4—of harmonically related components,
partial components which do not have substan
(4;) a “quint” tone in precisely proper relation
tial nodes at the point of attachment of the damp
ship (1.2:1) to the fundamental, and (5) a series
ing structure; hence the selectivity of action. The
(all above 4-times the frequency of the funda
choice of the material of the piece 28 and of the
mental) of the dissonant tones which must always
total mass of’the damping structure will of course
be to some extent present to create the typical
determine the degree of the action. When that
effects of bell or chime tones.
degree is very small, the effect of the structure
Of course in the foregoing series the funda
on the partial components not having substantial
mental (designated by 1) is a ?ctitious or sup
plied component. In many instances this will
not be found a shortcoming, because of the
strength of the tendency~above discussed-to
supply it. But in those cases wherein it may
be desired that it be an actual component, it may
be supplied by an additional, simultaneously ex
cited vibrator in the same manner as the added
hum component above discussed. Accordingly in
Figure 2 I‘ have illustrated a second supplemen
tary vibrator, designated as 33, Whose ?rst-partial
nodes at the point of attachment will be simply ‘
that of noticeably increasing the rates of damp
ing of those components in the output tone. When
that degree is larger, however, those rates of
damping will be so great that the components
may not be identi?ed over the general “clang”
' or other impulsive impression created at the in
ception of the tone, so that in ultimate effect the
damping structure will have served more nearly
as a simple attenuator or eliminator of those com—
ponents.
'
r
‘
frequency maybe chosen to form the “l” in the 7 0 By way of example, the damping structure 2'!
series. It may be secured to the main vibrator
has been shown in Figure 2 as attached to the
in similar manner to that above described for
vibrator at a point about .79 times the length of
32, and may extend upwardly alongside that sup
the vibrator from lug It. At this point the struc
plementary vibrator close enough thereto so that
ture has a signi?cant damping effect on all par
the single translating device 3! will be effective»
tials (of those up ‘to-“and including the ninth)‘
2,413,062
all
12
euceptingthe ?fth, sixthand ninth, each of which
ple round rods-maybe employed in substitution
hasa substantial node in this region. Thus in
the arrangement and use ofthe Figure-2 struc
ture as last above described, the effect of the
damping structure is to aid in the suppression
of the?rst, second and third partials, and to re
duce the “quint” (fourth partial) and some of
the higher dissonant partials (e. g., seventh and
for the vibrator above described. I have accord
ingly illustrated in Figure 7 a partial front ele
vational view of a round-rod vibrator 42 intended
for optional substitution for the vibrator !2 of
Figure 2.
The weight, when that is employed, for the
round rod may for example take the speci?cally
eighth), while leaving essentially unimpaired the
different form of a cylinder 35, having a bore of
?fth and sixth partials which are being relied
on for the production of the fundamental and of
the 2-times and 3-tirnes frequencies (and of
course leaving unimpaired the action of the sup
plementary vibrator means). It will vbe under
which the approximatelycentra1 portiont?a ?ts
the rod, and of which the outer portions 35b-are
slightly oversize. The damping structure for the
round rod may;for example take the ‘speci?cally
different form of .a cylindrical bushing 38 of the
stood, however, that this particular employment
dampinglmaterial and .a cylindrical member .39
of the damping means, while .a peculiarly favor
able one in certain instances, is primarily in
tended to be simplyillustrative of its use to cOn
surrounding 38 and Y‘ clamping it to .the rod—
though the member 39 may be omitted if the
mass of 38 be itself large enough for the desired
trol the output tone‘quality, .byattenuating cer
damping action.
Supplementary vibrators-may be employed with
tain ‘partials (especially low ones) not desired in
the output tone.
The structure of Figure 2, insofar as it com
bines, with translation from .a plurality of points
along a vibrator, a ?attened cross-sectional form
of the vibrator (e. g., a form inherently having a
preferred .plane of vibration), is one that I have
found broadly of great .uti1ity—and for a reason
not immediately apparent. This .reason vis
grounded in the propensity of any vibrator which
has similar vibratory propensities both in the
plane ‘of intended vibration and in all other
planesicontaining the vibrator (e. g., of any vi
brator round in cross-section), to shift the plane
of its vibration between that plane in which the
vibration was originally caused and the plane at
the round vibrator, if desired, in amanner anal
ogous to that discussed above for the rectangu
larly cross-sectioned vibrator. Accordingly I
have shown secured -to the rod 42, 'near the lug
l3 into which it is gripped, the base endsof two
supplementary vibrators 32’ and 33’, which may
respectively serve the functionsserved'by 32 and
33 in the structure of Figure 2. By way of ‘ex
ample two speci?cally different features have
been illustrated "in Figure -7 in connection ‘with
the supplementary vibrators-though it will ‘be
understood that thesefeatures are in no way lim
ited to the round, as ‘distinguished from rectan
gularly cross-sectioned, main vibrator. One of
these features is the formation of each supple
mentary vibrator as a relatively thinner element,
right angles thereto-this shift being frequently
for example of ‘piano wire, and the relatively
aslowly oscillatoryrone. Clearly this shiftingac
more appropriate use of .small terminal weights
tion, (even with a single translating device, will
(32a, 33a), rather than a thinningof these vibra
cause the translated output from the vibrator to
be modulated at the low frequencylof .the shift 40 tors near their bases, .to effect such control of
the second-.toe?rst partial frequency ratios of
ing; and to this extent only there is more or less
these vibrators; such weights may for example
apparent the desirability of employing with .a
be of solder. The other feature mentioned above
single translating device a vibrator structure
is the extension of these supplementary vibra
characterized by a preferred plane of vibration
(suchasshownfor a stringinPatentNo. 1,933,298 45 tors not upwardly as in Figure 2,.butdownwardly,
in general parallel to and alongside the main vi- I
tome).
brator '42, so that the translating ‘device 2| ‘active
.But I have discovered that such shifts of vi
for the main vibrator may at the same time serve
bration between the two planes vmay occur inde
as the translating device for the two supplemen
pendently for the respective several partial com
tary vibrators (the latter for ‘example being bent
ponents of vibration; and since the adjustments
appropriately to adjust ‘the ‘translation from each
ofa pluralityof translating devices and of their
without ‘disturbance of the adjustment of mag
outputs, for particular net translating actions-as
netic member l9, which latter adjustment will
to the several partials, are influenced by overall
dynamic conditions, the perfection of those net
adjustments for their purpose may be very seri- .
ously impaired .by the ‘shift of vibration plane.
have been effected as found necessary in connec
tion with the translation from the main vibrator) .
Hereinabove there have been described various
expedients for the elimination or attenuation of
And I have found, as may followfrom the fore
going once that .hasbeen appreciated, that the
various partial components-especially of low
use .of a vibrator characterized by a preferred
partial components which are inherently sepa
rated by relatively wide frequency intervals and
plane of vibration,-by reason of its elimination or
substantial elimination of the shifts of plane, fre
quently effects an ,unexpectedand great improve
ment in the perfection ofthe netor balanced ac
tion of a pluraltiy of .translating devices respec
tively associated with different parts ofthe vi- ‘
brator.
While this discovery andexpedient is not lim
ited to the ‘case of the :beam vibrators, it is of di
rect applicability thereto, and it is for this reason
thatI have-preferred, and haveillustrated in Fig
ure 2, the .rectangularly cross-sectioned vibrator.
It Will be understood, however, that ,manyof the
aspects of my invention are not limited to the
use of such vibrators, and that other forms of
“clamped-free” beam—-such forlexample as sim
for that broad reason, among others, are fre
quently of small utility in the production of the
most acceptable bell or chime tones. Thus for
example in the typical series of components for
an output tone set forth in detail above-the ?rst
two partials of the main vibrator are for prac
tical purposes absent, the third is present in at
most greatly attenuated [amplitude (supplying a
‘fsub-quint” hum tone), and thefourth is at least
somewhat attenuated.
A .result of this character may be achieved .by
the use, alternatively or additionally to the expe
dients above disclosed, of a high-pass?lter in
the output circuit of the translating means for
75 the main vibrator—which translating means may
2,418,062
13
be limited if desired to a single translating de
vice such as 2| (as by omission of the others or
adjustment of their potentiometer 22’ to render
them ineffective). Such a high-pass ?lter I have
indicated in Figure 2 as 42; it is shown connected
in the output circuit from the potentiometers 22
and 22’, prior to the merger with that output cir
cuit of the output circuit from potentiometer 30
for the supplementary vibrator means. -
in connection with “free-free” beams. Because
of the suspension which permits the “free-free”
nature of vibration of the latter beams (i. e., a
suspension which does not constrain the vibrator
against rotary movement about its support) , the
mean position of such a beam in space may vary
oscillatorily~the oscillatory variation of position
being for example the pendular swing of the vi_
brator about its support, above termed the “?rst
In Figure 2 there has been illustrated, though 10 partial” of its vibration in the generic View of the
actions of the two types of vibrators. While this
?rst partial might be utilized if desired, 'it is
aimost always an undesired partial; and pref
erably its complete elimination, in the mechanico
electric translation (from each individual trans
spring is to attenuate the ?rst-partial vibration
lation, when more than one is effected), is insured
of the vibrator l2—a vibration which is usually
by mounting the pick-ups on the vibrator, so that
thus far not mentioned, a helical spring 26 hav
ing its upper extremity secured in any convenient
manner to the bottom of the vibrator l2, and
its lower extremity secured to some stationary
member 25 therebelow. A useful function of this
an unused one, as has already appeared. This
mechanical attenuation of the vibration itself is
usually unnecessary insofar as mere elimination
of the ?rst partial from the output tone'is con—
cerned, when expedients such as already de
scribed are employed; but it is useful both in
avoiding undue swings of the free extremity of
the vibrator (correspondingly reducing the spac
ing which that must have from other objects),
they as well as the vibrator undergo the “?rst~
partial” movements.
.
One of the simplest forms of pick-up which
may be employed for mounting on the vibrator is
a piezo-electric translating unit. When this is
so mounted on the vibrator as to be subjected by
the vibrator vibration to an oscillatory elongating
,- and shortening tendency (e. a, secured to the
vibrator at all points along the unit in a direc
tion which is longitudinal both of the unit and
of the vibrator), it may be a simple, single crystal
of piezo-eleotric material (such as Rochelle salt)
The influence of such a restraining means as 26 30 with electrodes on its two sides forming its elec
on the frequencies of the partial components
trical terminals, I have generally preferred,
and in suppressing any possible tendencies to
ward modulation of the translation of higher
partial components at the ?rst-partial frequency.
(theoretically a. raising in?uence) sharply de
creases with increase in the number of the par
tial; and with a relatively weak tensioning of
the spring this in?uence will be altogether im- -
perceptible excepting on the frequency of the
?rst partial, which is ordinarily not being used
in any event.
,
The description proper of the embodiment of
Figure 2 may be completed by noting the cas
caded elements following the translating devices
and their respective potentiometers, abovemen~
tioned. These elements may comprise the cir
cuit G into which the outputs of the several trans
lating devices (i. e., the output terminals of the
?lter 43 and potentiometer 36 when those are
employed) are connected, for example in series
however, to employ a double-crystal unit of the
so-called “bi-morph” type-comprising two crys»
tals secured together so that bending of the unit
involves elongating and shortening tendencies in
the respective crystals, and having an electrode
between the crystals forming a ?rst terminal and
respective outer electrodes electrically connected
together to form the second terminal, an oscil
latory bending of the unit serving to cause a cor
responding voltage to appear across the terminals.
Such a unit is effective either when mounted as
abovementioned (then because of unequal clon~ '
gations and shortenings of its two crystals) or
broadly when mounted in any manner which
causes an oscillatory bending of the unit in its
longitudinal direction.
Accordingly, I shall ?rst '
relationship; the control system M, in which any
illustrate an embodiment of my invention ern~
and all known forms of control for the composite
ploying such
devices;
bi-morph
but itpiezoeelectric
Will be understood,
units as
oscillations in electronic musical instruments may 50 translating
be employed; the ampli?er 45; the volume con
will hereinafter be the subject of typical illustra—
trol 46; the further ampli?er 41; and the loud
tion, that many of the aspects of my invention
speaker or other electro-acoustic translating de
are generic to other forms of translating devices
vice 48. It will be understood that the elements
as well as these pieZo-electric units.
consecutively numbered from 43 through 43, as Li 421 In Figure 8 I illustrate a “free-free” beam vi
Well as the potentiometers 22 and 22’ and 36,
brator comprising a metal tube 52 suspended by
may if desired serve in common for a plurality of
a cord 53 from appropriate supporting pins 5|.
vibrators such as any one of those illustrated or
This tube may for example be of the material
described, respectively tuned to the several note
and type commonly used for the purely mechan
frequencies of a musical scale.
60 ico-acoustic production of chime tones, though
The consideration of this embodiment may be
no unnecessary limitation in this respect is in
completed by calling attention to the fact that,
tended.
Following conventional practise for
while for the sake of illustration the embodiment
such tubes, it may if desired be provided with a
and typical modi?cations thereof have been dis‘
52a secured within its top extremity, above
closed in considerable detail, and various typical ' plug
the level at which the cord 53 passes through the
adjustments and optional features separately
tube; this plug may for example be of insulating
considered, there are thereby intended no un
material, such as the phenol-resin composition
expressed limitations-such as to the particular
known ‘as “Bakelite.” Also following conven
partials to be elicited or suppressed, components
tional practise, the tube or vibrator 52 may be
to be added by supplementary vibrators, dampings TU subjected to impulse excitation, to place itinto
to be effected, particular forms of elements, or
vibration, by a hammer 5*? moved by 'a conven
the like.
While my invention has so far been described
in connection with “clamped-free” beams, it will
become apparent that it may also be carried out
tional means (such as an electromagnetic action)
not shown. Attention is called, however, to the
fact that, as shown in Figure 8, the hammer‘
proper isrsecured to its shank 54a, as through‘.
2,413,062
15
a bushing 54b lockable in any desired position
longitudinally of the shank, so that it may strike
the vibrator either in the very end portion of
the latter (e. g., opposite the plug 52a) as con
ventionally and as illustrated in full in Figure 8,
or at other points within the upper portion (for
example, the top quarter) of the length of the
vibrator.
In connectionwith the vibrator 52 of Figure 8
I have shown two translating devices SI and 6!’
which may be considered as respectively ful?ll
ing, in a general sense, the functions of the de~
vices 2! and 2!’ of Figure 2. These devices have
been shown as bi-morph piezo-electric units of
the type above described. Preferably, as a pro
tection against mechanical damage and atmos
pheric disintegrating effects, the translating
by the two pick-ups from the seccnd-partial‘vi
bration will be opposed against each other.
(This may in a typical case permit the connect
ing together of corresponding terminals of the
two units (it and 6! ’; and accordingly, if desired
to save conductors, the central electrode of each
unit may be electrically connected to the vibrator
immediately adjacent the unit, and a common
conductor'employed from the vibrator to one side
of each of the potentiometers. The other ter
minal of each unit may be electrically connected
to the respective‘ potentiometer by a respective
conductor passing through the plug 52a.) The
amplitudes of the composite oscillations trans
lated by each pick-up unit may be regulated by
the respective potentiometer; and the regulation
may for example be such that the second partial
is fully balanced out from the combined pick-up
units will be positioned inside the tubular vi
output. It will be seen from Figure 12 that at
brator, when that is large enough in diameter
(as assumed for the particularly illustrated vi 20 the same time there will be an inter-pick-up rein
brator) so that the units can be introduced and
positioned therewithin by the aid of appropriate
tools. The device 6l-illustrated on enlarged
scale in Figures 10 and 11-will be seen to com—
prise the two crystals Bla, the interconnected
forcement of the third partial, as well as of sev
eral of the partials higher than the third. Thus
this arrangement is well adapted for the produc
tion of a tone in which the third partial is to
form the fundamental. Furthermore, an off
balance adjustment for the second partial, in
outer electrodes Blb forming one electrical ter
either direction from true balance, will provide a
minal, and the central electrode Bic forming the
second-partial hum tone of any desired ampli
other electrical terminal. Because of the curved
tude relative to the rest of the tone.
(e g, concave) shape of the surface to which
The expedient of weighting to improve the in
the unit is to be secured, it may ?rst be cemented 30
ter-partial frequency ratios may be employed
to a thin slab Gld (for example of “Bakelite”)
‘ Whose opposite surface is curved to ?t, and will be
cemented into intimate permanent contact with,
the interior vibratorsurface. The translating
device GI’ may be a unit in all respects similar to
with the “free-free” as well as with the “clamped
free” vibrators. Accordingly in Figure 8 I have
shown, adjacent the bottom extremity of the vi
brator 52, a Weight '55, of generally cylindrical
form surrounding and adjustable along the vi
the unit 6%. (And it will be understood that the
brator. The bore of the Weight may have an ap
optional use of a simple, single rather than bi
proximately central portion 550; ?tting the vibra
morph, piezo-electric unit would in each unit in
tor, and slightly oversize portions 55b above and
volve simply the omission from each illustrated
unit of that one of the crystals and that one of 40 below 55a; a set screw 55c passing through 55a
may serve to hold the weight in place on the vi
the electrodes 6 lb which is further from the sur
brator. Further considerations regarding the‘
face of the vibrator.)
weight, having been detailed in connection with
The determination of proper positions of the
the earlier embodiment, need not now' be re
translating devices longitudinally along the vi
- peated.
brator involves considerations generally anal
In general, there are applicable to the “free
ogous to those above pointed out in connection
free” vibrator the considerations detailed above
_ with theivibrators of earlier ?gures. There is,
with respect to the use of the respective partials
however, a speci?c difference in the con?gura
of the “clamped-free” vibrator. Along lines al
tions which the vibrator assumes at the peaks
ready discussed for that case, it may be desirable
of its vibration at its several partial frequencies,
to assign a frequency other than that of the third
between the “clamped-free’? and the “free-free”
partial-for example, a frequency of half the
vibrators. Those con?gurations for the latter
?fth partial-as the “fundamental” or pitch-de
(considered without any weight analogous to IE)
are presented as the family of curves I02 through
termining frequency. As in that case, it will then
ill‘! in Figure 12. The speci?c differences from
usually be desirable to carry out the translation
in such a manner as to reduce the prominence of
Figure 4 (other than those second-order ones in
cidental to the contemplations of presence and
the third partial in the net translated oscillations,
absence of a weight in the respective ?gures) are
so that it at most supplies a hum tone. And as
in that case, this may be accomplished by prop
con?ned to the region of the vibrator which, for
the “clamped-free” vibrator, is adjacent the sup 60 erly re-positioning the translating devices—typi
cally, by placing them at a pair of positions of
ported end—though in this region they cannot be
neglected. In spite of the speci?c differences
which one incident will be a closer spacing to
each other. Thus the translating device further
just mentioned, if in the Figure-8 structure the
from the supported end (59’) may be replaced
pick-up 6| is positioned at (i. e., so that its longi
tudinal mean point is at) approximately .266
times the length of the vibrator, and the pick-up
6i ' is positioned at approximately .55 times that
length, from the supported end of the vibrator,
then there may be obtained an action generally
similar to that of the ?rst-mentioned adjustment
of the Figure-2 structure.
Thus the electrical outputs of the pick-ups 6i
and 61’ may be connected together through re
spective potentiometers 22 and 22' in such a
phase that the oscillations respectively translated
by one nearer the other device; and while this
may be nearer by any desired degree, with cor
responding effects (as brought out in connection
with the device 2 l ” in Figure 2), I have preferred
for most purposes, and have illustrated in Figure
TO 8, a quite near position, analogous to that of the
device 2 I "’ in Figure 2.
In Figure 8 the device so to be substituted for
Bi’ appears as 5V”; it may for example be a
piezo-electric unit such as already described.
Typically it may be positioned at .333 times the
17
2,413,062
length of the vibrator (when the device '6l is at
.266 times that length) from the supported end
of the vibrator. The substitution is indicated as
eifeoted by the switch ‘63. Assuming an adjust
18
thin vibrator having one end secured to 58 near
lug 5i, and extending downwardly alongside 58
so that the two in common will in?uence the
translating device t6. Control of the oscillation
ment of the outputs of El and 6V” so that the 5 output from ‘59 relative to that from 58 may of
second partial is balanced out, it will be seen
course be effected by bending of 59, as already
from Figure 12 that in the net translated oscil
discussed for the supplementary vibrators of ear
lations there will be a restricted translation of
lier ?gures.
the third partial, a medium translation of the
With the “free-free” main vibrator there may
fourth, and an almost normal translation of each 10 of course be employed, alternatively or addition
of the next several partials. Thus (as in the case
ally to the expedients already disclosed for the
of the tone from the Figure-2 embodiment inso
reduction or elimination of lower partials, the
far as that is supplied by the main vibrator)
high-pass ?lter means
which were disclosed in
there will be obtained a “sub-Quint” tone of re
connection with Figure 2. Accordingly I have
stricted amplitude, a “supplied” fundamental, a 15 shown, connected in the output circuits from pc
“quint” of medium amplitude, and a good devel
tentiometers 22 and 22’ as in Figure 2, the high
opment of further partials, of which the ?rst two
pass ?lter 43, which may be employed when de
will be of approximately Z-times and 3-times, re
sired for the function already made apparent.
spectively, the frequency of the fundamental.
I have thus far disclosed, as applied to the
And it will of course be understood that the ad 20 “free-free” vibrators, the use of expedients for
justments here mentioned in connection with the
the reduction or elimination of partials which are
Figure-8 structure are just as susceptible of shift
similar to those disclosed at an earlier point here
for the production of special effects, as are those
in for the "clamped-free” vibrators. There are,
of the Figure-2 structure as above described,
however, other expedients for that reduction or
When it is desired to expand the harmonic de
elimination which, while not in all respects lim
velopment just mentioned to include another
ited to the “free-free” vibrators, are especially
hum. tone and/or a real (in addition to a “sup
easy to carry out therewith. These include, for
plied”) fundamental-or, indeed, any other com
example, the elimination of an undesired low par
ponentor components-there may be utilized the
tial by the placement of the translating device
expedient disclosed above in connection with the ‘ quite exactly at a node for that partial, and the
Figure-2 structure: the supply of any or all those
accompanying elimination of another low partial
additional components from supplementary vi
brator means excited simultaneously with the
main vibrator. While there is again intended no
by the excitation of the vibrator at a node for
that other partial.
(In general, neither of these
manners of elimination will be relied on for the
unexpressed limitation as to the form or manner 35 ?rst partial of the “free-free” vibrator, in the ter
of simultaneous excitation of the supplementary
vibrator means, I have in Figure 8 by way of ex
ample shown those means as separate from the
main vibrator and subjected to separate excita
tion simultaneous with that of the main vibrator.
Thus at St I have illustrated a rail, to which
through lug 5'! there may be secured a “clamped
free” supplementary vibrator 58 in the typical
form of a round rod. The ?rst-partial frequency
of the supplementary vibrator may for example
be half the frequency assigned as the fundamen
tal of the main vibrator 52, so that it will con
tribute a sub-fundamental hum tone; and the
supplementary vibrator may if desired be slightly
thinned near its base (as at 58a) to bring its sec
ond-partial frequency to 31/2 or 4 times the fun
damental frequency assigned to 52 (as above dis
cussed for the supplementary vibrator 32). The
supplementary vibrator 58 may be arranged to be
struck by a hammer Ell, whose shank 64a is actu
ated simultaneously with the shank 54a of ham
mer 54, for example through electromagnetic ac
tion means well understood in the art and not
herein necessary to show. Translation from the
supplementary vibrator 58 may be eifected in any
convenient manner-typically by means of an 60
electromagnetic translating device or pick-up 60
minology herein employed; but the mounting of
the translating device or devices on the “free
free” vibrator has eliminated the ?rst partial,
rendering the manners of elimination just men
tioned particularly available for other low par
tials.)
-‘
Reference being had again to Figure 8, there
will be seen a translating unit 62 mounted on the
vibrator 52 at a lower position than those of the
translating units 6!, ii i ' and BI'”. For this point
there may be chosen one which is a node (or al
most a node) for one of the low partials to be
eliminated (or attenuated).
For example, for
elimination of the second partial this point may
be approximately .78 times the vibrator length
from the supported end of the Vibrator, which will
be seen from Figure 12 to be a node for the second
partial (that is, in the absence of weight 55, a
slight re~positioning—~readily determined by
test-being necessary for full elimination when
any given weight is employed). This translating
unit 62 may for example be of a form such as al
ready described for the unit 65. It may be sub
stituted for 6! by the switch 54; and at the same
time contributions from either 6|’ or 6l'” may
be avoided by moving the switch 63 to a blank
switch-point 53a. With such an adjustment, of
supported in spaced relation to the vibrator and
course, the translating unit 52 becomes the sole
for example having its output connected across
translating means effectively associated with the
potentiometer 30 (from which the oscillations 65 main
vibrator.
translated from the supplementary vibrator will
Further,
the hammer 54 may be re-positioned
be merged with those from the potenticmeters 22
along its shank 54a, for example to approximately
and 22’ for the main vibrator, as in the Figure-2
the position shown in Figure 8 in dotted lines.
structure) .
This
position may be chosen so that the hammer
One or more further supplementary vibrators,
such as second one 59, may be secured to 58 to 70 will strikethe vibrator at a point which is a node
(or almost a node) for another of the low partials
be simultaneously excited and to provide one or
to
be eliminated (or attenuated). For elimina
more other tone components—for example, an
tion of the third partial this point may be ap
actual “fundamental” for the output tone. A
proximately .13 times the length of the vibrator
'form which 59 may take is that of a relatively
75 from the supported end of the vibrator.
2,413,062
19
sired to achieve a more selective action, with min
With the structure adjusted as just described,
imum damping of certain selected partials. Ac
the fourth partial of the main vibrator 52 will be
cordingly I have shown in Figure 13 the support
the lowest partial to appear in the oscillations
of the vibrator, by a cord 53' of yieldable and en
translated from that vibrator. While this par
tial’might be relied on as the fundamental of the 5 ergy~absorptive material, at a point similar to
that employed for the damping structure 6? in
output tone, it is probable that in typical cases
Figures 8 and 9-az1 arrangement which may be
it may be more desirable to assign as that funda
made to approximate the e?ects described above
mental a frequency of half that of the ?fth par
for the vibrator equipped with that damping
tial, as to which the fourth partial will become a
“quint”, the ?fth partial an octave, and so on as 10 structure, without the actual use of such struc
above described. ri‘hen if there is desired a hum
tone and/or a real (as distinguished from a “sup
ture.
In the embodiment of Figures 8~9 (speci?cally,
means such as 58—58 may of course be relied on.
in Figure 9)
-e is iilustrated a feature permit~
ting an alternative achievement of a simultaneous
A hum tone may, however, be obtained without
the use of the supplementary vibrator means
is to be found in the screw or other member 69a
plied”) fundamental, supplementary vibrator
(e. g., with potentiometer 39 adjusted for ineffec
tiveness thereof), by slightly displacing the trans
lating unit or the striking point from that which
fully eliminates the respective partial-e. g., by
displacing the hammer upwardly along its shank
54a, so that it strikes above the node for the third
partial by whatever distance is required for de
velopment of a desired third-partial (in the typi
cal case abovementioned, “sub-quint”) hum tone.
And it will be understood that the adjustments
just suggested are not primarily limitative, but
rather are exemplary of eliminations, attenua
tions and control which may be effected by joint
regulation of striking point and single translat
ing point. Further, it will be appreciated that
the regulation of striking point offers a measure
of additional control even when a plurality of
translating devices are employed. For example,
with the devices 65 and BH’” in use as above de~
scribed, the last-mentioned adjustment of ham
mer 54- would serve fully or almost fully to elimi
nate the residual small amplitude of third-par
tial (e. g., “sub-Quint”) hum tone; or the ham
mer might be placed at (or nearly at) a node for 1
the fourth partial, to eliminate (or attenuate) the
otherwise medium amplitude which that partial
(for example, furnishing a “quint” component)
would otherwise furnish.
Damping means such as described in connection
with earlier embodiments may be employed with
the “free-free” vibrators. The damping means
may take the form of a structure El comprising a
ring d8 of a damping material such as above
supporting and damping function. This feature
secured in and projecting outwardly from the ring
iii} in the damping structure
‘This member
569a may be employed as a rigid support for the
vibrator 52,
e cord 53 then being omitted; in
spite of the ngidness of
the “free'ufree” vi
bratory nature is preserved, by reason of the pres
ence of the yieldable material 68-which will,
however, cooperate with the mass of the vibrator
in providing a c'rong damping action on all par
tial components not having substantial nodes in
its region. -11 this case, since the entire weight
of the vibrator is supported from the ring 59
through the piece es of damping material, it may
be desirable to cement the latter both to the vi
brator and to the ring 69 (rather than to rely
merely on frictional gripping).
With the “free-free” vibrator there may be em~
ploye-d a helical spring 65 corresponding to the
spring 25 disclosed
connection with the em
bo ‘iment of Figure 2. The spring 55 may have its
upper extremity secured in any convenient man
ner to a peripheral point at the bottom of the
vibrator 52, and its lower extremity secured to a
suitable stationary member 65. The functions
and frequency in?uences of the spring K35 will be
understood to be similar to those of the spring 25
already described~particular note being made of
the especial value of the restraint against undue
pendular excursions in the case of the “free-free”
vibrator, in which. case they otherwise may tend
to attain considerable magnitude. This is par
ticularly true, and the restraining means 65 of
particular value, when the hammer 55} is arranged
mentioned surrounding the vibrator, and a metal 50 to strike the vibrator at a point considerably re—
moved longitudinally of the vibrator from the
lic ring \69 surrounding the ring 58 and serving to
region of support of the vibrator.
build up the total mass of the structure to that
In the embodiment of Figures 8—9 I have
necessary for the desired degree of action. By
shown~speci?cally by illustration in Figure 9
way of example, the structure 6'! has been shown
a further feature which may be employed when
as positioned at approximately .066 times the
desired. This is the provision of a hammer 54’
length of the vibrator from the supported end,
arranged (on a shank Eta’, along which it may be
at which point the ?fth and sixth partials have
adjustable for purposes analogous to those for
substantial nodes. Accordingly these partials
which hammer 515 is adjustable) to strike the vi
will be little affected by the damping structure,
which will however be quite effective as to the 60 brator in a plane at right angles to that in which
the hammer 54 operates. The translating de
other partials.
vices, being arranged for effectiveness as to vi~
If the means which supports the f‘free-free”
brations in the plane of operation of hammer 54,
vibrator—-e. g._. the cord 53—-be made of mate
will not efficiently translate the vibrations of the
rial characterized by considerable energy ab
vibrator at and immediately following an impact
sorption, or damping influence, it itself will act
of hammer 54’ against the vibrator; but as those
as a damping means. As illustrated in Figures 8
vibrations
progress they will (beside retaining
and 9, thiscord is connected with the vibrator at
components in the plane of the actually-em
a point about .03 times the vibrator length from
ployed hammer 54') develop and retain com
the vibrator end; since this point is a node only
for some very high (and usually fairly weak) 70 ponents in the plane of effectiveness of the trans
lating devices. , Accordingly upon
excitation
partials, the use of an‘ appreciably energy-ab
of the vibrator by the hammer 5"’ there will be
sorptive material in this case would result in a
produced a tone of gradually rising initial ampli
rapid damping of all the more important vibra
tude, rather than one of the usual impactive in
tion components. While that may be desirable in
certain instances, it will more frequently be de 75 ception, The hammers 54 and 55:’ may of course
21
2,413,062
22
be either simultaneously or selectively operated,
introduction into the translated oscillations of
unwanted extraneous frequency components from
the resonant characteristics of pick-up and spring
according to the type of tone it is desired to pro
duce. When supplementary vibrator means are
employed and excited simultaneously with the
main vibrator, the full translation of impactive
components from the supplementary vibrator
means coupled with a translation from the main
may be avoided by such expedients as the me
chanical tuning of the combination of pick-up
and spring to a very low frequency, for example
below that e?ectively transmitted by the ampli
vibrator with small or no impactive components
(achieved as just described) makes possible a se
?er 45.
may be pointed out that to avoid an unwant
lective control of inception characteristics~ 10 edItdamping
action when a sizeable mass is sup
which may be considered a counterpart of the se
ported by the vibrator, that mass should in gen
lective control of the termination (damping)
eral be connected with the vibrator through
characteristics as by means already described.
means free of any signi?cant energy-dissipation
I have so far described the embodiment of ‘
tendencies. This was achieved in the case of the
Figures 8-9 with particular reference to internal— 15 piezo-electric
pick-ups above described (even
ly mounted pick-ups. and to pick-ups of the piezo
though they may be of relatively small mass) by
electric type. For reasons already apparent, these
reason of the substantial rigidity of the slabs
have certain advantages, The broader aspects of
(e. g., Bld) and cement through which they are
my invention are not, however, limited to use with
secured to the vibrator. On the other hand, this
such pick-ups. Instead of the piezo-electric pick
20 is achieved in the case or the pick-up 73 by the
ups there may be employed other pick-ups, for ex
ample of one or another of the types operating by
support of that pick-up through the spring ‘I2
which, while yieldable, may be substantially free
the vibratory change in relative positions of two
of energy-dissipating effects. If this low fre
quency be properly chosen and the excitation of
vibration strong enough, it may be relied on for
spaced elements (one of which may or may not
be the vibrator proper, as desired). A mounting
of the pick-ups external of the vibrator may of
course be employed. And if desired the mount~
ings may be such as to provide for the adjust
ment of the pick-ups longitudinally of the vi
brator.
Thus in Figure 8 I show, arranged to be sub—
the production of a vibrato effect.
The support by the vibrator of a pick-up ele~
ment which is to move vibratorily with respect to
the vibrator need not necessarily, however, be re
30 stricted to a substantially dissipationless sup
porting, if the mass of that element be relatively
stituted'for the pick-up Si or 62 by the switch 64,
a pick-up which is external of the vibrator and
which is of the electromagnetic type. Further by
negligible-for then its damping effect on the vi
brator will be negligible. Thus in Figure 8 I show
way of example, it has been shown as arranged '
there is employed a small armature supported by
another electromagnetic pick-up 17, in which
to be positioned where desired longitudinally of
the vibrator through the intermediary of a very
appreciably dissipative element. This pick-up T!
the vibrator; it has, however, been speci?cally
shown at a longitudinal position similar to that
of the pick-up 62 above described.
Reference being had to Figure 8, there will be
seen a ring 10 surrounding the vibrator 52; this
has been shown, by way of example, as not ar
ranged for adjustment longitudinally of the vi
bator; and the position in which it is illustrated
is an approximately complementary one to that
of the pick-up 13 (or 62)—i. e., at a point approX~
imately .22 times the length of the vibrator from
the supported end, at which point the relative
strengths of the several partials (at least for the
unweighted vibrator) tend to be similar to those
at the position of 13 (or B2). The pick-up 1'! may
be electrically substituted for SI or 62 or 13 by the
40
ring may for example have an internal diameter
slightly larger than the external diameter of the
vibrator, but it is held in any desired position
along the latter by a screw ‘ll threaded through
the ring into abutment against the vibrator. The
ring 10 may be of magnetic material, such as iron
or steel. Secured in the ring 10, for example
diametrically opposite to the screw 1 I , are the ex
tremities of a generally circularly formed light‘ 50
leaf spring 12, this spring extending upwardly
from one of its secured extremities and curving
?rst away from the w'brator, then downwardly,
then toward the vibrator, and ?nally upwardly
to its other secured extremity. Secured to the
central part of the spring and extending there
from into close spaced relationship to the ring 19
is a pole member 14, preferably of soft iron. Sur
extending outwardly therefrom in alignment with
the pole member 14 is a short bar magnet 16;
the pole member, coil and magnet together form
ing an electromagnetic pick-up 73.
The pick-up 13 is designed to operate by reason
of vibratory variation ‘of the spacing between the
ring 16 (which of course vibrates with the vi~
brator) and the adjacent end of the pole member
14. While the latter (and with it the balance
of the pick-up 13) is also supported by the vi
brator, that support is through the intermediary
The pick-up 11 may include a pole member 78
terminally secured to the vibrator and extending
horizontally therefrom.
For magnetizing this
pole member there may for example be supported
on it one end portion of a small bar magnet '19.
Li Cir
Surrounding the pole member '!8 beyond the mag
net 19 is the schematically shown coil 80. Onto
the outer end of the pole member ‘i8 may be ce~
mented a small and relatively thin disc or pad
rounding this pole member is a. coil 15 (sche~
matically shown) ; and secured to the spring and
switch 64.
8|, preferably of very yieldable and permissibly
130
resilient material; and onto the outer surface
of the pad 8| may be cemented a small and light
armature 82 of magnetic material, such as a thin
iron armature.
While the inertia of the armature 82 is very
f small, it nevertheless will be sufficient so that
the vibration of the vibrator is of somewhat at
tenuated amplitude as it appears in the arma
ture; the attenuation represents vibratory com
pression and expansion of the pad iii, and conse
quent vibration of the armature relative to the
pole member in accordance with the vibration of
the vibrator. While this type of pick-up may be
of the spring 12; and the pick-up, because of its
inertia, will tend to remain stationary, this be~
characterized by somewhat lower ef?ciency than
ing permitted by a vibratory ?exure of the spring
that
last described, it has the advantage of per
72 in accordance with the vibrator vibration. The 75 mitting
critical or far over-critical damping in the
2,413,062
v23
pad-and-armature system, with consequent Eli-1 -
ination of any spurious frequency components
without reliance on any mechanical tuning.
Another form of pick-up which operates by the
vibratory change in relative positions of two
spaced elements and which may be employed is
an electrodynamic piolr-up'—in which the two
elements are respectively a looped conductor (i. e.,
a coil) and a magnetic~?eld-producing element.
Thus in the fractional Figure ill I show a bar
magnet 85% secured. to the vibrator 52 and extend
horizontally therefrom, and a coil 85 coaxial
with and freely surrounding the magnet Bll-the
coil 85 for example being supported from the vi
brator by light leaf springs 86, which may be me
24
there may be connected, in series, a voltage source
H6 and a high resistance H5; and across H5
i 15, through a condenser Hi, there may be con
nected the input of the cascade £4i-—5—6—1—~8
abovernentioned.
If the voltage source
Hi3 be of steady or direct
voltage, there will be charged through resistance
H5 the capacity between the vibrator and the
electrode 5 l i; vibratory variations in this capac
ity will cause a variation of the voltage across it,
and the variations in
voltage will be trans—
mitted through the condenser i l"! to the cascade
abovementioned. On the other hand if the source
lit be of oscillations of sup-eraudible frequency,
a current of that frequency will flow through I l5
and 5 l6 and through the capacity between vibra
chanically tuned with the mass of the coil to a
tor and electrode i l l ; vibratory variations of this
very low frequency. In view of the inertia of the
capacity will modulate this current at the vibra
coil it will tend to remain stationary when the
tor vibrational frequencies. A voltage of the so
vibrator is vibrated; and the resulting vibratory
modulated superaudible-frequency oscillations
variation in the relationship of the coil to the 20
will appear across lit-l l6, and will be trans
?eld-producing magnet will cause the induction
mitted through the condenser to the cascade—in
in the coil of vibration-rcpresenting oscillations.
which the ampli?er {it will in this instance be
It will be appreciated that in the electrody
operated as a demodulator as well as an ampli?er.
naniic piclr~up just described a substantial mass n
The electrode of an electrostatic pick-up may
.20
is supported by, and movable relative to, the vi
of course
mounted internally of the vibrator if
brator, by means of substantially dissipationless
desired. Accordingly I show another electrode
elements. An electrodynamic ' pick-up may
E2! in the form of a light metal sheet curved into
equally well, however, employ a very small mass
a cylindrical section preferably of radius slightly
movable relative to the vibrator and supported by
smaller than that of the inside of the Vibrator.
means characterized by substantial dissipation. 30 The
side-to-side center of this sheet may be con
Thus
the fractional Figure 15 I show a small
nected to the vibrator by a small vertica1 strip
post 39 secured to the vibrator 52 and extending
222 of cement; and as an additional securing
horizontally a short distance ‘therefrom to sup
port a coil 9-0 coaxial with the post. Onto the
outer end surface of this coil may be cemented
a disc or pad ti (similar for example to the pad
8.! above described), and onto the outer surface
of the pad may be cemented a miniature magnet
92 (for example of the highly efficient iron-alu
minum-nickel-cobalt alloy commonly known as
“Alnico”) magnetized in a horizontal direction.
Vibrations of the vibrator will appear in the mag
net in somewhat attenuated amplitude; the at
tenuation representsvibratory compression and
expansion of the pad, and thus vibration of the
magnet relative to the coil, with consequent in
duction in the latter of vibration-representing cs
cillations.
Still another form of pick-up which operates
by the vibratory change in relative positions of
two spaced elements and which may be employed
an electrostatic pick-up-—the simplest embodi
ment of which comprises an electrode in spaced
I relationship to the vibrator itself. Since the elec
trode is readily made of very small mass, the pres
once or absence of dissipation in the supporting
means between it and the vibrator will in the
usual case not be important. In Figure 16 I show
secured to the vibrator 52, at several points there
along so that several partial compositions are
selectively‘ available, a number of electrostatic
pick-ups. A very simple one appears as the light
metal sheet or electrode ill, curved, into a cylin
drical section preferably of slightly greater radius
than that of the outside of the vibrator. The
center of this electrode ill may be insulatedly
secured to the outside of the vibrator by means
of the screw H2 and the thin insulating washers
H3, a flexible conductor lit being electrically
means there may be stuck across the center of the
inner surface of the electrode, and onto the vi.
brator surface thereabcve and therebelow, a Ver
tical strip 523 of tape. A flexible conductor I24
may be connected to the center of the electrode.
By a switch lilo this conductor may be substi
i-uted for the conductor 2 ii, thereby substituting
the pick-up last described for that previously
described.
Another form of electrostatic pick-up may, as
illustrated in Figure
comprise a light metal
45 sheet l3l acting as electrode, cemented to the
outer surface of a "pad it? of very soft, yieldable
material whose inner surface is cemented to the
vibrator. A conductor 234 may be connected to
this electrode, and maybe substituted for con
ductors i it and 123 by the switch 558.
Another construction illustrated in Figure 16
comprises a strip electrode iii-i having one ex
tremity secured (as by cementing) to a block
“.12 of insulating material carried by the vibra
55 tor, the electrode being curved so that its prin
cipal portion extends along the vibrator in very
close spaced relationship thereto. The showing
of electrode Elli includes
preferred thin coat
ing iii-3 of rubber on its inner surface adjacent
the vibrator, to prevent actual short~circuiting in
the case of maladjustment Or the like.
There is
also illustrated in Figure 16 another strip elec
trode lél, differing from till in that, instead of
being supported in cantilever, it is supported at
both extremities on respective insulating blocks
[52. It too may have a thin coating (list) of rub
ber on its inner surface, if desired.
Connections to the electrodes hill and Lil may
be made by conductors Hit and 115i, respectively.
In Figure 16 these have been shown as electri
connected with the electrode immediately adja
cally connected together, to illustrate the joint use
cent the washers.
of two electrostatic pick-ups. In this case the
Another ?exible conductor H9 may be electri;
relative contributions of the two may be adjustef.
cally connected with the vibrator in any conven
by differential adjustment of the spacings of the
ient manner, as schematically illustrated in Fig
ure 16. Between the conductors H0 and H4 75 two electrodes from the vibrator, as well as by
25
2,413,062
choice of their respective areas. The phase re—
lationship between the two may be most simply
controlled by appropriately choosing the sides of
the vibrator on which the two electrodes are re
spectively positioned; as illustrated, they are on
opposite sides, for opposition
partials Which a
in similar phase.
conductors M4 and I54 may be
for
H4, I24 and I34 by the switch ISO,substituted
to
render
the
combined electrodes I 4: and I 5| e?ective as the
translating means.
2. In a musical instrument: the combination of
a beam vibrator supported in the neighborhood
of one extremity thereof and from the vibration
of Which output sound is translated, and means
under tension secured to the other extremity of
said vibrator.
While I have described my invention in terms
of particular embodiments thereof, and with ref
erence to two typical forms of vibrator (“clamped
free” and “free-free” beams), I intend thereby
instrument including a beam
for vibration: a Weight for al
tering the ratios between lower partial frequen
cies in said vibration, a longitudinally restricted
oscillations from said vibration and comprising
electro-magnetic means secured to and vibratable
with said vibrator, an armature, and yieldable
means supporting said armature from said vibra
tor and in spaced relation to said electromagnetic
means.
BENJAMIN F. MIESSNER.
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