US2616970A - Device for the transmission by electrical means of oscillations of acoustic frequency - Google Patents

Device for the transmission by electrical means of oscillations of acoustic frequency Download PDF

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Publication number
US2616970A
US2616970A US66814A US6681448A US2616970A US 2616970 A US2616970 A US 2616970A US 66814 A US66814 A US 66814A US 6681448 A US6681448 A US 6681448A US 2616970 A US2616970 A US 2616970A
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frequency
oscillations
channels
frequencies
channel
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Expired - Lifetime
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US66814A
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English (en)
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Broos Henricus Adrianus
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Hartford National Bank and Trust Co
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Hartford National Bank and Trust Co
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S5/00—Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation 
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/12—Circuits for transducers, loudspeakers or microphones for distributing signals to two or more loudspeakers
    • Y—GENERAL 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S84/00—Music
    • Y10S84/26—Reverberation
    • Y—GENERAL 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S84/00—Music
    • Y10S84/27—Stereo

Definitions

  • This invention relates to devices for the transmission by electrical means of oscillations of acoustic frequency, the electrical oscillations representing the first-mentioned oscillations being set up in a frequency-dependent manner, with the use of filters across at least two channels, each comprising only one filter, by applying a voltage, if desired adjustable, such that for obtaining a spatial impression during reproduction, if desired via recording of the sound on a support, the strength of reproduction increases in one channel and decreases in the other channel upon changing from a frequency or group of frequencies to an adjacent frequency or group of frequencies.
  • spatial impression is to be understood to mean the impression as if the sound originates from one or more sound sources exhibiting spatial extensiveness.
  • a certain extent of spatial impression is already obtained with a known device in which electrical oscillations of acoustic frequency, coming from one channel are divided with the use of some filters which partly overlap over an equal number of reproducing channels.
  • the spatial impression obtained when the loud speakers are arranged in a row with some spacing and ranged according to increasing or decreasing ranges of frequencies is such that the lowest tones are heard coming from the outer loudspeaker at one side and the highest tones from the outer loudspeaker at the other side, the intermediate loudspeaker reproducing the intermediate ranges of frequencies. Since the transmission characteristic curves of the filters for two adjacent ranges of frequencies partly overlap, the frequencies of the overlapping region are reproduced by two loudspeakers, but not in the same strength ratio for each frequency. The image of the spatial position of such a frequency is thus located between the two loudspeakers and spatially varies in position for each frequency of the overlapping region.
  • the imperfection of this device resides in the fact that during the reproduction of those frequencies which are not located in the overlapping portion of the transmission characteristic curve of twoadjacent filters, but which are passed by only one filter, all these frequencies are reproduced at the same spatial area, namely that of the loudspeaker associated with the filter concerned. With chromatic increase of frequencies a reproduction is thus obtained in which the sound image is at rest at the outer loudspeaker,
  • this disadvantage is obviated in that the filters exhibit frequency characteristic curves such that the whole or substantially the whole ran e of frequencies to be reproduced by at least one of the channels, at least in so far as it contributes to the spatial impression, is also reproduced by one or more of the other channels to an extent which contributes to the effect.
  • extent which contributes to the eifect is to be understood to mean that a determined minimum difference in ratio between the sound strengths of two frequencies or groups of frequencies to be positioned side by side in the sound image is required in each of at least two channels, viz. a difference in ratio such that the sound images produced of the two frequencies or groups offrequencies occupy preceptibly. different positions in space. As mentioned before, this may be ensured with the device according to the invention by causing the strength of reproduction to increase in at least one of the channels and to decrease in at least one of the other channels upon change in frequency.
  • the aim will be to ensure that the ratio between the sum of the strengths of reproduction of a determined frequency in the various channels and that of the other frequencies is equal to the ratio between the strengths of the oscillations of the corresponding frequencies upon generation.
  • each frequency has. an individual position or the groups are of equal size
  • the distance between these frequencies or groups will be chosen to be equal, so that the filters for each channel are required to be such that in the case of two channels and with logarithmic increase of frequency the voltage transmitted by one filter increases to such extent that the sound strength reproduced by the associated channel exhibits a substantially linear increase and, for the other-filter, decreases to such extent that the sound strength reproduced by the other channel exhibits a substantially linear decrease.
  • the outer loudspeaker which may be positioned with some spacing, may each comprise a filter such that their sound strength increases and decreases in substantially linear proportion with the logarithm of frequency in a range of, for example, from 500 to 1200 c/sec.
  • the central loudspeaker in this case reproduces the frequencies below 500 c./sec., which frequencies, as is well known, do not contribute to the spatial impression.
  • the device according to the invention permits inter alia of reproducing with a spatial impression electrical oscillations which are not transmitted stereophonically by microphones and which originate, for example, from a piano and, if desired, have been recorded afterwards in the form of a sound track.
  • the sound image thereof may be such as to convey the impression as if it displaces in space, dependently on frequency, in a similar manner as heard by the player of the instrument himself.
  • a device according to the invention enables the sound image of such instruments nevertheless to produce a spatial impression.
  • the device according to the invention permits of obtaining a spatial impression more particularly of a source of oscillations of acoustic frequency which exhibits a spatial extensiveness, which is small with respect to the spatial impression of the sound image thereof.
  • a musical box all the acoustic oscillations of which seem to originate from the same place, provides a sound image such that the different tones are heard at different places, hence in such manner that, for example, all tones are heard side by side, in which event the total width of the sound image may be equal to the distance between the loudspeakers of the reproducing channels.
  • Fig. 1 shows a device in which each of two channels comprises a filter such that a strength of reproduction as shown in Fig. 2 is obtained for each channel.
  • Fig. 3 shows a device for three channels. The reproduction characteristic curve of this device is shown in Fig. 4.
  • Figs 5 and 6 are variants of Figs. 3 and 4.
  • reference numeral i designates a channel for the transmission of electrical oscil lation of acoustic frequency.
  • the oscillations are supplied to two channels i and 2, each comprising a filter F1, F2, respectively.
  • the filters are dependent on frequency in such manner that the strength of the sound to be reproduced by loudspeakers b is dependent on frequency in a manner as represented in Fig. 2 by the curve A1 for channel 5 and by the curve A: for channel 2.
  • a determined frequency will thus be reproduced by the loudspeaker of channel i and by that of channel 2.
  • the position occupied by this frequency in the sound image will thus be located, according to the ratio between the strengths of reproduction of the two channels, between the loudspeakers of the channels, the distance between the two loudspeakers being equal to the total width of the sound image of the whole of the range of frequencies.
  • the electrical oscillations of the single channel a may originate either from a microphone or from a record. As an alternative, they may be supplied by other generating members such, for example, as electric musical instruments.
  • Fig. 3 shows the image of a three-channel system for the reproduction of sound.
  • the electrical oscillations of the single channel a are supplied to the three channels 3, 4, 5, which comsupplied to the three channels 3, i, 5, which comprise the frequency-dependent filters F3, F4, F5 respectively.
  • Fig. 4 which shows the reproduction curves of the three channels of Fig. 3, the loudspeaker b of channel 3 only reproduces the low frequencies. The higher frequencies are transmitted with different strengths by the two channels 5 and 5 and the sound image is thus reproduced dependently on frequency between the loudspeakers of the said channels.
  • Fig. 5 shows a device which is a variant of Fig. 3.
  • the channels 5, l, 6, comprise filters F3, F7, F8 respectively such that the sound upon being re-- produced through the same number of channels via a record produced by members 0 in the form of three tracks, has a strength which is dependent on frequency, as indicated in Fig 6 by A0 for the channel 6 and by A7 and A3 for the channels 7 and 8.
  • the low tones are also divided over two channels so that each tone occupies its own position. Consequently, upon change from a very low frequency to a higher frequency, the strength of reproduction of the frequencies reproduced by the channels 6 and I will in this device increase in channel I and decrease in channel t.
  • the device may be used with advantage with instruments exhibiting a spatial extensiveness which is small with respect to the spatial impression of the sound image thereof, such, for example, as a musical box.
  • said second network having a frequency-response characteristic at which the amplitude of oscillations within the remaining high-frequency band in said range applied to said second reproducer decreases in accordance with frequency
  • said third network having a frequency-response characteristic at which the amplitude of oscillations within said high-frequency band appliedto said third reproducer increases in accordance with frequency

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Stereophonic System (AREA)
  • Circuit For Audible Band Transducer (AREA)
US66814A 1948-02-11 1948-12-22 Device for the transmission by electrical means of oscillations of acoustic frequency Expired - Lifetime US2616970A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL271987X 1948-02-11

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US2616970A true US2616970A (en) 1952-11-04

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US (1) US2616970A (de)
CH (1) CH271987A (de)
DE (1) DE960732C (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2802061A (en) * 1954-07-02 1957-08-06 Perspecta Sound Inc Perspective sound apparatus
US2993090A (en) * 1955-03-16 1961-07-18 Arf Products Electrostatic speaker circuit
US3038966A (en) * 1959-04-01 1962-06-12 Stereotone Inc Sound reproducing systems
US3046337A (en) * 1957-08-05 1962-07-24 Hamner Electronics Company Inc Stereophonic sound
US3147333A (en) * 1960-07-27 1964-09-01 Baldwin Co D H Audio modulation system
US4121059A (en) * 1975-04-17 1978-10-17 Nippon Hoso Kyokai Sound field expanding device
US4239939A (en) * 1979-03-09 1980-12-16 Rca Corporation Stereophonic sound synthesizer

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1098997B (de) * 1955-02-07 1961-02-09 Saba Gmbh Anordnung zur pseudostereophonischen Wiedergabe in elektroakustischen Geraeten, insbesondere in Rundfunk-, Fernseh- und Phonogeraeten
DE1171016B (de) * 1959-11-14 1964-05-27 Erhart Zitzlaff Anordnung zur pseudostereophonischen Klangwiedergabe
DE1282718B (de) * 1959-11-14 1968-11-14 Erhart Zitzlaff Anordnung zur stereophonischen und pseudo-stereophonischen Klangwiedergabe

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1674683A (en) * 1925-03-31 1928-06-26 Lorenz C Ag Arrangement for uniform electrical sound transmission
US2093540A (en) * 1931-12-14 1937-09-21 Emi Ltd Sound-transmission, sound-recording, and sound-reproducing system
US2098372A (en) * 1933-10-23 1937-11-09 Emi Ltd Sound-transmission, sound-recording, and sound-reproducing system
US2261628A (en) * 1940-03-22 1941-11-04 Bell Telephone Labor Inc Stereophonic reproduction by carrier wave transmission
US2352696A (en) * 1940-07-24 1944-07-04 Boer Kornelis De Device for the stereophonic registration, transmission, and reproduction of sounds

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB297308A (en) * 1927-09-17 1928-10-04 Forest Phonofilms Ltd De Improvements in or connected with sound reproducing
US2098561A (en) * 1934-02-09 1937-11-09 Rca Corp System for producing stereosonic effects
US2179840A (en) * 1938-05-03 1939-11-14 Frida Bucky Loudspeaker arrangement

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1674683A (en) * 1925-03-31 1928-06-26 Lorenz C Ag Arrangement for uniform electrical sound transmission
US2093540A (en) * 1931-12-14 1937-09-21 Emi Ltd Sound-transmission, sound-recording, and sound-reproducing system
US2098372A (en) * 1933-10-23 1937-11-09 Emi Ltd Sound-transmission, sound-recording, and sound-reproducing system
US2261628A (en) * 1940-03-22 1941-11-04 Bell Telephone Labor Inc Stereophonic reproduction by carrier wave transmission
US2352696A (en) * 1940-07-24 1944-07-04 Boer Kornelis De Device for the stereophonic registration, transmission, and reproduction of sounds

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2802061A (en) * 1954-07-02 1957-08-06 Perspecta Sound Inc Perspective sound apparatus
US2993090A (en) * 1955-03-16 1961-07-18 Arf Products Electrostatic speaker circuit
US3046337A (en) * 1957-08-05 1962-07-24 Hamner Electronics Company Inc Stereophonic sound
US3038966A (en) * 1959-04-01 1962-06-12 Stereotone Inc Sound reproducing systems
US3147333A (en) * 1960-07-27 1964-09-01 Baldwin Co D H Audio modulation system
US4121059A (en) * 1975-04-17 1978-10-17 Nippon Hoso Kyokai Sound field expanding device
US4239939A (en) * 1979-03-09 1980-12-16 Rca Corporation Stereophonic sound synthesizer

Also Published As

Publication number Publication date
CH271987A (de) 1950-11-30
DE960732C (de) 1957-03-28

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