US2421424A - Reverberation method and system - Google Patents

Reverberation method and system Download PDF

Info

Publication number
US2421424A
US2421424A US576812A US57681245A US2421424A US 2421424 A US2421424 A US 2421424A US 576812 A US576812 A US 576812A US 57681245 A US57681245 A US 57681245A US 2421424 A US2421424 A US 2421424A
Authority
US
United States
Prior art keywords
reverberation
sound
frequency
ultrasonic
signal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US576812A
Inventor
Kreuzer Barton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by RCA Corp filed Critical RCA Corp
Priority to US576812A priority Critical patent/US2421424A/en
Application granted granted Critical
Publication of US2421424A publication Critical patent/US2421424A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G10MUSICAL INSTRUMENTS; ACOUSTICS
    • G10KSOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K15/00Acoustics not otherwise provided for
    • G10K15/08Arrangements for producing a reverberation or echo sound
    • G10K15/10Arrangements for producing a reverberation or echo sound using time-delay networks comprising electromechanical or electro-acoustic devices
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S84/00Music
    • Y10S84/26Reverberation

Definitions

  • This invention relates to sound recording methods and systems, and particularly to a sound rerecording system wherein the original sound record is modied with respect to amplitude or frequency, or both.
  • the sound may be recorded in a studio or on a set, which is actually only a portion of the entire scene, and thus, the quality of the sound is not appropriate to the scene being depicted in the picture. For instance, only two or three sides of a large hall or cave may be used, and the sound detected from the actors therein does not have the characteristic it would have had if produced in the actual hall or cave. However, by rerecording, the sound may be characterized by varying the amplitude and frequency relationship of its components, and by introducing reverberation, to give it the quality it would have had if actually recorded at the scene of action.
  • reverberation is also used to improve or restore noisy records.
  • reverberation chambers are employed, and have been ernployed for some time.
  • Reverberation chambers are simply enclosed spaces into which sound is projected by a speaker and detected by a microphone spacially disposed with respect to the speaker.
  • a reverberation chamber of large size it is desirable to have a reverberation chamber of large size in order to get a true and accurate sound modification to simulate the scene, and such space is usually not readily available.
  • the present invention is directed to a system which permits the use of the unused spaces in a studio or building not otherwise suitable for this purpose, such as a basement area, the plenum space in a building, or the actual recording stage itself While in use.
  • Reverberation may, of course, be added to and during the original recording from a recording stage, the present invention permitting the stage to be used simultaneously for both the original sound source and the reverberation chamber.
  • One of the important features of the invention is the use of an ultra or supersonic frequency, which, of course, is not only inaudible to the performers, but also is inaudible to the audio detecting elements or microphones. Since the ultrasonic carrier modulated by an audio signal occupies only a relatively narrow band in its spectrum, a very high quality result is obtainable, while the use of an ultrasonic frequency as a carrier permits the reverberation chambers to be tanks or pipes filled with a liquid,
  • the principal object of the invention is to facilitate the modification of a sound wave as recorded.
  • Another object of the invention is to provide an improved method of and system for obtaining reverberation in a signal being transmitted or recorded.
  • a further object of the invention is to provide an improved method of reverberating an audio signal.
  • a further object of the invention is to obtain reverberation in space not normally suitable therefor.
  • a still further object of the invention is to obtain reverberation of an audio signal by modulating an ultrasonic signal, which is reverberated and thereafter detected to obtain a reverberated audio signal.
  • a source of signal currents to be reverberated is shown at 5 as a reproducer, which may be either film or disc, although it is to be understood that this source could be a microphone directly detecting the original sound source or sources.
  • the output of the reproducer is fed into an amplier 6, the output of which is divided, one portion going to an amplifier 8 feeding a recorder il and a monitoring speaker l2 through a mixer 9.
  • This channel contains the essential elements of a normal recording system, the mixer operator varying the amplitude of the currents in the proper amounts within the limits of the recorder II.
  • the othe1 ⁇ portion of the output from the amplier 6 is fed into a modulator I5 which is supplied with an ultrasonic carrier frequency, such as 30,000 cycles, from a generator I6, the output of the modulator being fed to an ultrasonic reproducing speaker I8 in a reverberation chamber 20.
  • the ultrasonic frequency sidebands produced by modulation are reverberated in the chamber 20 and picked up by an ultrasonic microphone 2 I, amplilied in amplier 22, and detected in a demodulator 24 to obtain the original audio frequencies.
  • rihe reverberated audio signal is then ampliiied in amplifier 25, impressed on a mixer 26, and then on the recorder II and monitor I2.
  • the normal and reverberated currents are mixed together in the desired proportions for recording into the final record.
  • the entire signal may be passed through the reverberation chamber or the operator may use only that portion passing through the reverberation chamber.
  • the ultrasonic frequency spectrum is very large compared with the audio frequency range which determines the Widths of the sidebands (one of which may be suppressed)
  • the same ultrasonic wave translator and detector could be used for a plurality of carriers, the carriers being separated by electrical band pass lters, as is well-known in the art.
  • the unused spaces of a building may now serve as reverberation chambers, such as the basement or attic, or the actual recording stage during the original sound Droduction.
  • the audio frequency elements are insensitive to the ultrasonic frequencies, and the ultrasonic elements are not sensitive to the audio frequencies, so there is no interference therebetween.
  • the range of the ultrasonic reproducer and detector is large and only a Very narrow range is employed, a uniform response is obtained.
  • a reverberation system comprising a plurality of generators of super audible electrical currents, each current having a different frequency, a plurality of signals in the audio spectrurn, a reverberation chamber, means for modulating each of said super audible currents with a respective audio signal, means for simultaneously generating ultrasonic waves from said products of modulation Within said chamber, means for translating said reverberated Waves into corre sponding electrical currents, and a demodulator for each of said electrical currents of different frequency,
  • the method of generating and detecting a signal in a certain area and simultaneously regenerating and again detecting said signal in said area comprising detecting sound waves from the original source of said Waves in a certain area, modulating a supersonic carrier frequency with the products of detection, reproducing the products of modulation in said certain area, and detecting said reproduced products of modulation.
  • a method of producing artiiicial reverberations on a sound stage without interfering with the normal recording operations being conducted thereon comprising producing an audible sound signal on said stage, detecting said signal during the production thereof, generating a super-audible carrier frequency, modulating said carrier with said detected signal, translating said products of modulation into ultrasonic waves Within the space of said sound stage, detecting said ultrasonic waves within said space, and demodulating said detected currents to obtain a reverberated original signal.
  • the method of obtaining varying reverberation characteristics of an audio signal without modifying the reverberation chamber, itself comprising generating a super-audible carrier of predetermined frequency, varying the frequency of said carrier to obtain desired changes in reverberation characteristics, modulating said carrier with said audible signal, generating ultrasonic waves with the products of modulation, reverberating said waves, translating said waves into electrical currents, and demodulating said last mentioned currents.

Description

June 3, 1947 B. vKREUzr-:R
REVERBERATION METHOD AND SYSTEM Filed Feb` 8, 1945 @N MHQN NSK@ SQQ Patented June 3, 1947 UNITED REVERBERATION METHOD AND SYSTEM Barton Kreuzer, Philadelphia, Pa., assignor to Radio Corporation of America, a corporation of Delaware Application February 8, 1945, Serial No. 576,812
Claims.
This invention relates to sound recording methods and systems, and particularly to a sound rerecording system wherein the original sound record is modied with respect to amplitude or frequency, or both.
It is Well-known that sound records, especially those which accompany motion pictures are generally rerecorded, while records made for radio broadcasts or home reproduction in phonographs may also be rerecorded before release. In motion picture work, rerecording is employed to combine dialogue, background effects, and/or music into a composite record for the picture, the various components being modified either with respect to amplitude or frequency, or both. Amplitude and frequency modiiications are also made during the rerocording of a single prerecorded record, particularly to simulate the sound as it would occur at the place of the scene. The sound may be recorded in a studio or on a set, which is actually only a portion of the entire scene, and thus, the quality of the sound is not appropriate to the scene being depicted in the picture. For instance, only two or three sides of a large hall or cave may be used, and the sound detected from the actors therein does not have the characteristic it would have had if produced in the actual hall or cave. However, by rerecording, the sound may be characterized by varying the amplitude and frequency relationship of its components, and by introducing reverberation, to give it the quality it would have had if actually recorded at the scene of action.
As disclosed in my copending application, Ser. No. 576,811, filed Feb. 8, 1945, reverberation is also used to improve or restore noisy records. In accomplishing sound wave modification, reverberation chambers are employed, and have been ernployed for some time. Reverberation chambers are simply enclosed spaces into which sound is projected by a speaker and detected by a microphone spacially disposed with respect to the speaker. To simulate large halls, railroad stations, caves, and the like, it is desirable to have a reverberation chamber of large size in order to get a true and accurate sound modification to simulate the scene, and such space is usually not readily available. The present invention is directed to a system which permits the use of the unused spaces in a studio or building not otherwise suitable for this purpose, such as a basement area, the plenum space in a building, or the actual recording stage itself While in use. Reverberation may, of course, be added to and during the original recording from a recording stage, the present invention permitting the stage to be used simultaneously for both the original sound source and the reverberation chamber.
One of the important features of the invention is the use of an ultra or supersonic frequency, which, of course, is not only inaudible to the performers, but also is inaudible to the audio detecting elements or microphones. Since the ultrasonic carrier modulated by an audio signal occupies only a relatively narrow band in its spectrum, a very high quality result is obtainable, while the use of an ultrasonic frequency as a carrier permits the reverberation chambers to be tanks or pipes filled with a liquid,
The principal object of the invention, therefore, is to facilitate the modification of a sound wave as recorded.
Another object of the invention is to provide an improved method of and system for obtaining reverberation in a signal being transmitted or recorded.
A further object of the invention is to provide an improved method of reverberating an audio signal.
A further object of the invention is to obtain reverberation in space not normally suitable therefor.
A still further object of the invention is to obtain reverberation of an audio signal by modulating an ultrasonic signal, which is reverberated and thereafter detected to obtain a reverberated audio signal.
Although the novel features which are believed to -be characteristic of this invention Will be pointed out with particularity in the appended claims, the manner of its organization and the mode of its operation will be better Vunderstood by referring to the following description read in conjunction with the accompanying drawings forming a part hereof, in which the single figure is a diagrammatic arrangement of a recording or rerecording sytem embodying the invention.
Referring now to the drawing, a source of signal currents to be reverberated is shown at 5 as a reproducer, which may be either film or disc, although it is to be understood that this source could be a microphone directly detecting the original sound source or sources. The output of the reproducer is fed into an amplier 6, the output of which is divided, one portion going to an amplifier 8 feeding a recorder il and a monitoring speaker l2 through a mixer 9. This channel contains the essential elements of a normal recording system, the mixer operator varying the amplitude of the currents in the proper amounts within the limits of the recorder II.
The othe1` portion of the output from the amplier 6 is fed into a modulator I5 which is supplied with an ultrasonic carrier frequency, such as 30,000 cycles, from a generator I6, the output of the modulator being fed to an ultrasonic reproducing speaker I8 in a reverberation chamber 20. The ultrasonic frequency sidebands produced by modulation are reverberated in the chamber 20 and picked up by an ultrasonic microphone 2 I, amplilied in amplier 22, and detected in a demodulator 24 to obtain the original audio frequencies. rihe reverberated audio signal is then ampliiied in amplifier 25, impressed on a mixer 26, and then on the recorder II and monitor I2. By the proper adjustments of the mixers 9 and 26, as indicated in the monitor I2, the normal and reverberated currents are mixed together in the desired proportions for recording into the final record.
Although a split channel has been illustrated wherein only a portion of the signal is reverberated, it will be understood that the entire signal may be passed through the reverberation chamber or the operator may use only that portion passing through the reverberation chamber. Alsoy since the ultrasonic frequency spectrum is very large compared with the audio frequency range which determines the Widths of the sidebands (one of which may be suppressed), it is feasible to utilize the reverberation chamber for reverberating more than one audio signal simultaneously. That is, by the use of a second reproducer, shown at 30, and another detector, shown at 3I, two or more audio signals could be reverberated simultaneously by using a different carrier frequency for each audio signal. Furthermore, the same ultrasonic wave translator and detector could be used for a plurality of carriers, the carriers being separated by electrical band pass lters, as is well-known in the art.
As mentioned above, the unused spaces of a building may now serve as reverberation chambers, such as the basement or attic, or the actual recording stage during the original sound Droduction. In the latter instance, the audio frequency elements are insensitive to the ultrasonic frequencies, and the ultrasonic elements are not sensitive to the audio frequencies, so there is no interference therebetween. Also, since the range of the ultrasonic reproducer and detector is large and only a Very narrow range is employed, a uniform response is obtained.
By the use of ultrasonic frequencies as the reverberation medium, tanks or pipes lled with liquid can be used with under water sound propagators and detectors. By varying the tuning of the carrier generator, various reverberation characteristics are obtainable, thus avoiding changing the size of the chamber as is now necessary with audio frequency chambers. The system thus is particularly flexible to provide a wide range of sound characteristics covering spaces having a wide range in size, while permitting the same chamber to be used for reverberating several signals simultaneously.
I claim as my invention:
l. A reverberation system comprising a plurality of generators of super audible electrical currents, each current having a different frequency, a plurality of signals in the audio spectrurn, a reverberation chamber, means for modulating each of said super audible currents with a respective audio signal, means for simultaneously generating ultrasonic waves from said products of modulation Within said chamber, means for translating said reverberated Waves into corre sponding electrical currents, and a demodulator for each of said electrical currents of different frequency,
2. The method of generating and detecting a signal in a certain area and simultaneously regenerating and again detecting said signal in said area comprising detecting sound waves from the original source of said Waves in a certain area, modulating a supersonic carrier frequency with the products of detection, reproducing the products of modulation in said certain area, and detecting said reproduced products of modulation.
3. The method in accordance with claim 2, in which said detected products of modulation are combined with said origina-l products of detection.
4. A method of producing artiiicial reverberations on a sound stage without interfering with the normal recording operations being conducted thereon comprising producing an audible sound signal on said stage, detecting said signal during the production thereof, generating a super-audible carrier frequency, modulating said carrier with said detected signal, translating said products of modulation into ultrasonic waves Within the space of said sound stage, detecting said ultrasonic waves within said space, and demodulating said detected currents to obtain a reverberated original signal.
5. The method of obtaining varying reverberation characteristics of an audio signal without modifying the reverberation chamber, itself, comprising generating a super-audible carrier of predetermined frequency, varying the frequency of said carrier to obtain desired changes in reverberation characteristics, modulating said carrier with said audible signal, generating ultrasonic waves with the products of modulation, reverberating said waves, translating said waves into electrical currents, and demodulating said last mentioned currents.
BARTON KREUZER REFERENCES CITED rThe following references are of record in the le of this patent:
UNITED STATES PATENTS Number Name Date 2,318,417 Phelps May 4, 1943 1,853,286 Round Apr. 12, 1932
US576812A 1945-02-08 1945-02-08 Reverberation method and system Expired - Lifetime US2421424A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US576812A US2421424A (en) 1945-02-08 1945-02-08 Reverberation method and system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US576812A US2421424A (en) 1945-02-08 1945-02-08 Reverberation method and system

Publications (1)

Publication Number Publication Date
US2421424A true US2421424A (en) 1947-06-03

Family

ID=24306103

Family Applications (1)

Application Number Title Priority Date Filing Date
US576812A Expired - Lifetime US2421424A (en) 1945-02-08 1945-02-08 Reverberation method and system

Country Status (1)

Country Link
US (1) US2421424A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2493638A (en) * 1946-06-22 1950-01-03 Rca Corp Synthetic reverberation system
US3075044A (en) * 1958-05-05 1963-01-22 Tonalyzer Inc Method and apparatus for obtaining sound
US3172954A (en) * 1965-03-09 Acoustic apparatus
US3189686A (en) * 1961-08-18 1965-06-15 Baldwin Co D H Transducer and mounting for mechanical delay lines
US3506773A (en) * 1967-03-16 1970-04-14 Hammond Organ Co Device for producing stringed instrument or muted horn resonant tones employing a microphone inside or near a speaker enclosure
US3614320A (en) * 1968-12-13 1971-10-19 Rca Corp Stereophonic sound enhancement system with reverberation chamber
US8837745B2 (en) 2011-07-13 2014-09-16 Ecolivegreen Corp. Electro-acoustic audio reverberation device and method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1853286A (en) * 1926-05-13 1932-04-12 Rca Corp Transmission and reproduction of sound
US2318417A (en) * 1942-06-02 1943-05-04 Gen Electric Artificial reverberation system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1853286A (en) * 1926-05-13 1932-04-12 Rca Corp Transmission and reproduction of sound
US2318417A (en) * 1942-06-02 1943-05-04 Gen Electric Artificial reverberation system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3172954A (en) * 1965-03-09 Acoustic apparatus
US2493638A (en) * 1946-06-22 1950-01-03 Rca Corp Synthetic reverberation system
US3075044A (en) * 1958-05-05 1963-01-22 Tonalyzer Inc Method and apparatus for obtaining sound
US3189686A (en) * 1961-08-18 1965-06-15 Baldwin Co D H Transducer and mounting for mechanical delay lines
US3506773A (en) * 1967-03-16 1970-04-14 Hammond Organ Co Device for producing stringed instrument or muted horn resonant tones employing a microphone inside or near a speaker enclosure
US3614320A (en) * 1968-12-13 1971-10-19 Rca Corp Stereophonic sound enhancement system with reverberation chamber
US8837745B2 (en) 2011-07-13 2014-09-16 Ecolivegreen Corp. Electro-acoustic audio reverberation device and method
US9396720B2 (en) 2011-07-13 2016-07-19 Ecolivegreen Corp. Electro-acoustic audio reverberation device

Similar Documents

Publication Publication Date Title
US3686471A (en) System for recording and/or reproducing four channel signals on a record disc
US2461344A (en) Signal transmission and receiving apparatus
Watkinson The art of sound reproduction
US5159703A (en) Silent subliminal presentation system
ATE22641T1 (en) MAGNETIC RECORDING AND PLAYBACK SYSTEM.
US3401237A (en) Simultaneous recording of two signals per channel
US3973839A (en) Special effects generation and control system for motion pictures
US2421424A (en) Reverberation method and system
US1765735A (en) Recording and reproducing system
US2927963A (en) Single channel binaural or stereo-phonic sound system
Clark et al. The" Stereosonic" recording and reproducing system
US2904632A (en) Stereophonic sound propagation system
US2245652A (en) Method of and apparatus for the reproduction of sound
US3118977A (en) Multi-groove stereophonic sound recording and reproducing system
US1859423A (en) Sound recording
US2499593A (en) Reverberation time measuring system
US2846519A (en) Apparatus for pseudo-stereophonic sound reproduction
Klapholz Fantasia: Innovations in sound
US3070669A (en) Stereophonic sound recording and reproduction
USRE30278E (en) Special effects generation and control system for motion pictures
Frayne et al. A short history of motion-picture sound recording in the united states
JPS60103506A (en) Signal recording and reproducing device
US3008011A (en) Control-tone perspective sound system
US2083385A (en) Sound recording system
US1799795A (en) Sound recording and reproducing