US3719908A - Device for creating artificial reverberation - Google Patents

Device for creating artificial reverberation Download PDF

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Publication number
US3719908A
US3719908A US00141056A US3719908DA US3719908A US 3719908 A US3719908 A US 3719908A US 00141056 A US00141056 A US 00141056A US 3719908D A US3719908D A US 3719908DA US 3719908 A US3719908 A US 3719908A
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United States
Prior art keywords
systems
pick
driver
creation
symmetry
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Expired - Lifetime
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US00141056A
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English (en)
Inventor
W Fidi
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AKG Acoustics GmbH
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AKG Akustische und Kino Geraete GmbH
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K15/00—Acoustics not otherwise provided for
    • G10K15/08—Arrangements for producing a reverberation or echo sound
    • G10K15/10—Arrangements for producing a reverberation or echo sound using time-delay networks comprising electromechanical or electro-acoustic devices

Definitions

  • ABSTRACT In a device for the creation of artificial reverberation using single or multi-dimensional wave guides with 2n input systems and 2m pick-up systems, of equal sensitivity, where n and m are any positive integers, the input and pick-up systems are located on an axis of symmetry of the wave guide in symmetrical relation to the other axis of symmetry thereof.
  • the input and pick-up systems may all be located on the same axis of symmetry or they may be located on different axes of symmetry;
  • the signal to be reverberated either is supplied to all the input systems in-phase, with the pickup systems being connected in pairs in phase operation, or the signal to be reverberated is supplied to the input systems in pairs in phase opposition and all the pick-up systems are connected in-phase.
  • the reverberated signals are supplied, from the pick-up systems, to at least one pick-up amplifier.
  • the wave guide may be a helical spring, constituting a single-dimensional wave guide, or may be a thin plate, constituting a multi-dimensional wave guide.
  • the degree of disintegration increases with increasing time, that is the time elapsing since impression of the signal on the wave guide.
  • the disintegration is obtained, in a known manner, in that'the gauge of the spring and also its restoring forces are statistically varied by a special physical treatment of the spring.
  • the reverberation is produced artificially, for example, by means of a helical spring stimulated to torsional vibrations and having a transit time of about 100 msec and a statistical mass and elasticity distribution, it is found that, if a single pulse is impressed at one end, this pulse is received by the pick-up system, at the other end, relatively unaltered. If onewere to travel with the pick-up system along the spring toward the impressing, driver, or input system, the first pick-up pulse of the impressed or input signal would appear more and more clearly and unaltered at. the output of the pick-up system, whereas all further pulses of the impressed signal appear more and more disintegrated according to their distance in time from the stimulation of the helical spring.
  • This invention relatesto devices for creating artificial reverberation using wave guides and, more particu-. larly, to an improved device of this nature in which the artificial reverberation produced closely approaches natural reverberation corresponding to the natural room acoustics.
  • the invention relates to a device for the creation of artificial reverberation by means of a one-dimensional or 'multi-dimensional wave guide and Zn driver and 2m pick-up systems of equal sensitivity, where n and m are any positive integers.
  • a one-dimensional wave guide is understood one whose length exceeds all other dimensions by a considerable multiple, for example a long helical spring.
  • a multi-dimensional wave guide is understood a plate whose length and width may be a multiple of the plate thickness, in which case one may speak approximately of a two-dimensional structure.
  • the driver and pick-up systems are located on one of the axes of symmetry of the wave guide, and are arranged symmetrically with respect to the other axis of symmetry of the wave guide, the driver and pick-up systems either all lying on the same axis of symmetry or on different axes of symmetry.
  • the signal to be reverberated is supplied in-phase to all driver systems and the pick-up systems are connected together in pairs in phase opposition.
  • the signal to be reverberated can be supplied to the driver systems in pairs in phase opposition, and the pick-up systems may be connected in pairs inphase.
  • the reverberated signals are supplied to one or more pick-up amplifiers.
  • the invention is applicable also to multi-dimensional wave guides, for example to a thin plate stimulated to bending vibrations.
  • the diffuse signal components are, in this case, greater from the start than in one-dimesional wave guides, they still are not great enough, in comparison to the natural room acoustics, so that also here the idea of the invention increases the ratio of the diffuse components to the strictly correlated components, and thus increases the liveness.
  • the arrangement then could be such that two input or driver systems and two pick up systems lie on one of the axes of symmetry and are arranged symmetrically with respect to the other axis of symmetry, the input and pick-up systems being located either all on the same axis or on different axes.
  • An object of the invention is to provide an improved device with a creation of artificial reverberation.
  • Another object of the invention is to provide such a device using either single or multi'dimensional wave guides with 2n driver systems and 2m pick-up systems of equal intensity, where n and m are any positive integers.
  • a further object of the invention is to provide such a device in which the artificial reverberation very closely approaches natural reverberation.
  • FIG. 1 is a schematic illustration of the principle of the invention
  • FIGS. 2, 3 and 4 are pulse sequences explaining the effect of the application of the principles of the invention to a device for creating artificial reverberation
  • FIG. 5 schematically illustrates a preferred embodiment of the invention utilizing a helical spring
  • FIG. 6 illustrates a similar embodiment utilizing a thin plate as the wave guide.
  • FIG. 1 a one-dimensional wave guide W in the form of a tensioned helical spring stimulated to torsional vibrations.
  • input or driver systems Z1 and Z2 which are at the ends of spring W, and respective pick-up systems A1 and A2 for each of the input systems.
  • the input systems are indicated by arrows directed toward helical spring W, and the pick-up systems by arrows pointing away from helical spring W.
  • the two input systems Z1 and Z2 are disposed, with equal polarity, at the output of an input amplifier (not shown), while the'pick-up systems A1 and A2 are connected, with opposite polarity, to the pick-up amplifier VA,this being symbolized by the crossing of the input lines to the amplifier.
  • a pulse is applied to the input systems Z1 and Z2, these systems transmit to helical spring W simultaneously and in-phase, so that a pulse traverses helical spring W from left to right, and an identical or similar pulse traverses helical spring W from right to left.
  • the pulse originating from system Z1 arrives at pick-up system Al after the time T1
  • the pulse originating from system Z2 arrives at pick-up system A2 after the same time T1.
  • similar electrical pulses which, however, since the windings of the pick-up systems A] and A2 are connected electrically in opposition, do not become operativeat the input of amplifier VA, as they cancel each other out.
  • FIGS. 2 and 3 showing those pulse sequences which, after stimulation of the wave guide by a single pulse, occur in the form of electrical oscillations at the outputs of the two pick-up systems A1, A2.
  • FIG. 2 represents the output voltage of pick-up system A1, as a function of time
  • FIG. 3 represents the output of the pickup system A2, as a function of time.
  • the first echo is indicated at l, the second at 2, etc. It is evident that these echos occur with great strength as to amplitude, and have few diffuse components therebetween.
  • the pure echos become smaller and smaller (4, 5, 6, etc.) while, between the echos, the diffuse components continue to increase in number, a process which occurs also in natural reverberation.
  • the little-deformed first pulses l, 2, 3, etc. which hardly exist in natural reverberation, are disturbing.
  • the invention arrangement compensates the first echos, the result of which is visible in FIG. 4 in the form of a pulse diagram of the voltage at the input of the pick-up amplifier VA.
  • the first echos l, 2, 3, etc. cancel each other out by the electrical opposition connection of the pick-up systems, leaving only those residual voltage components which are completely irregular, that is unsymmetrical. After conversion to sound vibration, they result in a tone pattern which is typical of natural reverberation.
  • a simplification as to the arrangement of the systems can be obtained by combining each input system with a pick-up system to form a mechanical unit, but with the combined input and pick-up systems being mutually independent electrically and magnetically.
  • Such an arrangement is illustrated schematically in FIG. 5, in which the systems 21, A1 and Z2, A2 are combined to form mechanical units, with each unit being arranged at a respective end of the onedimensional wave guide W.
  • FIG. 6 illustrates the application of the invention to a reverberation device including a so-called reverberation plate P which is caused to undergo bending vibrations.
  • the drive or input systems Z1, Z2 lie on opposite sides of the axis of symmetry N at equal distances a on the axis of symmetry M.
  • pick-up systems A1, A2 are arranged on the axis of symmetry N at equal distances b from the axis of symmetry M. If a pulse is imparted to plate P through the drive or input system Z1, Z2, plate P goes into bending vibrations, which propagate like waves on a water surface after a stone has been thrown into the water. At least the first pulses arriving at pickup systems Al, A2, and which would contribute substantially to falsifying the tone pattern of the artificially produced reverberation, arrive at the pick-up systems essentially undeformed, cancelling each other out.
  • the greatest liveness is attained when the corresponding picked up signals are connected together strictly in phase opposition on the assumption of equal conversion or transducing functions of the transducers.
  • the degree of compensation By varying the degree of compensation, different effects can be obtained.
  • the compensation can be madecompletely disconnectable, the impression being created, without the compensation, that the sound event is in the foreground and the reverberation arrises from the depth of the room and is clearly perceptible as separate.
  • the sound event moves more and more into the depth of the room until, in the end, the optimally attainable reverberation exists. It is thus possible, in a simulated manner, to let the sound event apparently travel in the room at will, by variation of the degree of compensation, for example, in that the voltage is tapped by the pick-up systems by means of an adjustable voltage divider included in at least one pick-up system.
  • the device having 2n driver systems and 2m pick-up systems," of equal sensitivity, where n and m are any positive integers, so that the number of pairs of driver systems is equal to the number of pairs of pick-up systems, the improvement comprising, in combination, said driver and pick-up systems being located in one axis of symmetry of the wave guide, having mutually perpendicular axes of symmetry, and arranged symmetrically relative to the other axis of symmetry of the wave guide; the input signal to be reverberated being supplied to all said driver systems and the output signal being derived from all of said pick-up systems oneof said driver system and said pickup system having its pairs in-phase and the other having its pairs in phase opposition.
  • the improvement claimed in claim 1 in which the signal to be reverberated is supplied to all said driver systems in-phase; said pick-up'systems being connected together, in pairs, in phase opposition.
  • the improvement claimed in claim 1 in which the wave guide is a helical spring constituting a one-dimensional wave guide.
  • each driver system is combined with a respective pickup system to form a mechanical unit in which the two combined systems are uncoupled electrically as well as magnetically.
  • the improvement claimed in claim 1 in which the wave guide is a helical spring constituting a one-dimensional wave guide.
  • each unit comprises one driver system and one pick -up system, arranged symmetrically with respect to the midpoint of said spring.
  • said wave guide is a multi-dimensional wave guide constituted by a thin plate; and separate driver and pickup systems associated with said thin plate and arranged on both axes of symmetry and in each case symmetrically with respect to the other axis of symmetry.
  • said wave guide is a multi-dimensional wave guide constituted by a thin plate; and units, each comprising a driver system and a pick-up system, associated with said thin plate and arranged on both axes of symmetry, in each case symmetrically with respect to the other axis of symmetry.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)
US00141056A 1970-04-20 1971-04-16 Device for creating artificial reverberation Expired - Lifetime US3719908A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT358270A AT300400B (de) 1970-04-20 1970-04-20 Einrichtung zur Erzeugung künstlichen Nachhalles

Publications (1)

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US3719908A true US3719908A (en) 1973-03-06

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US00141056A Expired - Lifetime US3719908A (en) 1970-04-20 1971-04-16 Device for creating artificial reverberation

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US (1) US3719908A (de)
JP (1) JPS5318857B1 (de)
AT (1) AT300400B (de)
CA (1) CA936476A (de)
CH (1) CH522261A (de)
DE (1) DE2118292A1 (de)
FR (1) FR2089746A5 (de)
GB (1) GB1304118A (de)
NL (1) NL7105030A (de)
SE (1) SE366185B (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5431591A (en) * 1994-02-01 1995-07-11 Muzzi; Juan Carlos C. Helical spring pressure activated musical toy
US6000991A (en) * 1998-03-26 1999-12-14 Pragmatic Designs, Inc. Helical coil spring toy and a response device therefor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3517344A (en) * 1966-12-06 1970-06-23 Akg Akustische Kino Geraete Delay device particularly for the production of artificial reverberation
US3564462A (en) * 1967-11-29 1971-02-16 Akg Akustische Kino Geraete Helical spring for artificial reverberation devices
US3587006A (en) * 1967-12-07 1971-06-22 Akg Akustische Kino Geraete Arrangement for producing artificial reverberation comprising frequency dividing means

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3517344A (en) * 1966-12-06 1970-06-23 Akg Akustische Kino Geraete Delay device particularly for the production of artificial reverberation
US3564462A (en) * 1967-11-29 1971-02-16 Akg Akustische Kino Geraete Helical spring for artificial reverberation devices
US3587006A (en) * 1967-12-07 1971-06-22 Akg Akustische Kino Geraete Arrangement for producing artificial reverberation comprising frequency dividing means

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5431591A (en) * 1994-02-01 1995-07-11 Muzzi; Juan Carlos C. Helical spring pressure activated musical toy
US6000991A (en) * 1998-03-26 1999-12-14 Pragmatic Designs, Inc. Helical coil spring toy and a response device therefor

Also Published As

Publication number Publication date
AT300400B (de) 1972-07-25
NL7105030A (de) 1971-10-22
DE2118292B2 (de) 1980-02-14
GB1304118A (de) 1973-01-24
JPS5318857B1 (de) 1978-06-17
FR2089746A5 (de) 1972-01-07
DE2118292A1 (de) 1971-11-04
CH522261A (de) 1972-06-15
CA936476A (en) 1973-11-06
DE2118292C3 (de) 1980-10-16
SE366185B (de) 1974-04-08

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