GB1579571A - Signal processing method and apparatus - Google Patents
Signal processing method and apparatus Download PDFInfo
- Publication number
- GB1579571A GB1579571A GB1084877A GB1084877A GB1579571A GB 1579571 A GB1579571 A GB 1579571A GB 1084877 A GB1084877 A GB 1084877A GB 1084877 A GB1084877 A GB 1084877A GB 1579571 A GB1579571 A GB 1579571A
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- GB
- United Kingdom
- Prior art keywords
- signal
- harmonic
- creator
- frequencies
- pass filter
- 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
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/32—Modifications of amplifiers to reduce non-linear distortion
- H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
- H03F1/3276—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits using the nonlinearity inherent to components, e.g. a diode
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/32—Modifications of amplifiers to reduce non-linear distortion
- H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
- H03F1/3264—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits in audio amplifiers
- H03F1/327—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits in audio amplifiers to emulate discharge tube amplifier characteristics
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Power Engineering (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Multimedia (AREA)
- Tone Control, Compression And Expansion, Limiting Amplitude (AREA)
- Amplifiers (AREA)
- Stereophonic System (AREA)
- Electrophonic Musical Instruments (AREA)
- Signal Processing Not Specific To The Method Of Recording And Reproducing (AREA)
Description
(54) SIGNAL PROCESSING METHOD AND APPARATUS
(71) We, ITX LTD., a Corporation incorporated under the laws of the State of
California, United States of America, having a place of business at 7801 Melrose Avenue,
Los Angeles, California 90046, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement:
This invention relates to electronically processed sound. More particularly, this invention relates to a method and apparatus for enhancing the quality, clarity, presence, intelligibility and other characteristics of electronically processed sound.The invention is especially useful with, but not exclusively limited to, sound recording equipment, sound reproduction equipment, sound reinforcement equipment, sound analysis equipment and sound transmission equipment.
In U.S. Patent 2,866,849 there is disclosed an apparatus for improving sounds of music and speech in which an audio signal is split into two signal paths and the signal in one path is passed successively through an amplifier, a 3KC high pass filter, a harmonic producer, a 6KC high pass filter and an amplifier and is then combined, either electrically or acoustically, with the signal in the other path.
In U.S. Patent 2,852,604, there is disclosed a sound reproduction apparatus in which a monaural electrical signal is divided into two paths and the signal in one path is passed through a time delay mechanism. The two signals are then converted to sound through separate speakers.
In U.S. Patent 3,219,757, there is disclosed a sound reproduction apparatus in which a monaural electrical signal is divided into two paths and the signal in one path is passed through a non-linear frequency dependent phase delay circuit. The two signals are then mixed in two different ways. One of the mixed signals is converted to sound through one speaker and the other mixed signal is converted to sound through another speaker.
In U.S. Patent 3,560,656 there is disclosed a sound reproduction apparatus in which a monaural electrical signal is divided into two signal paths and the signal in one path is passed through a phase changing circuit. The two signals are then converted to sound through separate spaced apart speakers, with the sound emerging from both speakers having the same amplitude.
Other examples of electronic sound processing apparatus pertinent in one way or another to this invention may be found in U.S. Patent 2,866,849; U.S. Patent 2,953,644; U.S.
Patent 3,127,476; U.S. Patent 3,591,699; U.S. Patent 3,723,633; U.S. Patent 3,745,254;
U.S. Patent 3,819,861; U.S. Patent 3,828,133; and U.S. Patent 3,890,466.
According to one aspect of the invention there is provided a method of improving the quality of a signal containing frequencies in the audio frequency spectrum comprising: (a) splitting the signal into two signal paths; (b) passing the signal in one of the paths through a high pass filter designed to shift the phase of the signal passed in a frequency dependent manner; (c) passing those frequencies in the output signal of the high pass filter whose amplitudes are above a preselected level into a harmonic creator, the level of the input to the harmonic creator varying directly with the level of the output from the high pass filter; (d) attenuating all frequencies in the signal emerging from the harmonic creator a uniform amount to the level of the signal in the outer path; and (e) combining the attenuated signal containing the harmonics and the fundamental frequencies from which the harmonics are created with the signal in the other path.
According to another aspect of the invention there is provided apparatus for use in processing a signal containing frequencies in the audio frequency spectrum comprising: means for dividing said signal into two signal paths; a frequency dependent, phase shifting, high pass filter disposed along one path for filtering out frequencies in said path below a particular frequency level; a harmonic creator; means coupled between the output of the high pass filter and the input of the harmonic creator for controlling the input to the harmonic creator in accordance with the amplitude level of the output signal from the high pass filter; the attenuator at the output of the harmonic creator for attenuating all frequencies in the output signal a uniform amount; and means for combining the signals travelling along each path.
The amount by which the excited signal is attenuated is dependent on the type of the audio information being processed and the ultimate use of the electronically processed information. In most cases where the sound being processed is music or speech, the excited signal is attenuated to about between 20% and 70% of the amplitude of the unaltered signal.
Examples of the invention will now be described with reference to the accompanying drawings in which:
Figure 1 is a block diagram of one embodiment of the invention
Figure 2 is a block diagram of another embodiment of the invention;
Figure 3 is a circuit diagram of a vacuum tube version of the exciter circuit shown in
Figures 1 and 2;
Figure 4 is a graph illustrating the frequency dependent phase shifting characteristics of the exciter circuit in Figure 3;
Figure 5 is a block diagram of a two channel apparatus incorporating the invention;
Figure 6 is a circuit diagram of a solid state version of the exciter circuit shown in Figures 1 and 2;
Figure 7 is a plot of the transfer function of the harmonic creator in Figure 6; and
Figure 8 is a plot of the gain and phase of the signal emerging from the high pass filter in
Figure 6.
In Figure 1, there is shown a source 11 of monaural electrical signals. Source 11 may be a microphone, a radio tuner and amplifier combination, an electrical pickup from a record player or a magnetic sound head associated with a magnetic tape or any other device whose output is a monaural electrical signal. The output from source 11 is passed through an amplifier 13 and is then divided into two discrete signal paths 15 and 17. The signal travelling along path 17 is passed in succession through an exciter circuit 19, an amplitude attenuator 21 and is then combined in a mixer 20 with the signal travelling along path 15.
The combined signal is passed through an amplifier 23 and then fed into an output transducer 25, such as a loudspeaker or a magnetic tape or an engraved disc or a paper print-out. The exciter circuit 19 includes high pass filter means and harmonic creator means. The harmonic creator means is designed to create low order harmonics above a preselected threshold of frequencies passed by the high pass filter means.
In the Figure 2 embodiment, the signal from the amplitude attenuator 21 is then passed through an amplifier 27 to an output transducer 29 instead of being passed through the amplifier 23 and is then combined with the signal travelling along path 15 as in the Figure 1 embodiment.
In Figure 3 there is shown a schematic diagram of a vacuum tube version of the exciter circuit 19. The circuit 19 is made up basically of six triodes, a filter circuit, a signal splitting network, two bridge circuits and various auxiliary components.
A monaural electrical signal is applied to the exciter circuit 19 through input terminal 51.
The signal emerging from the input terminal 51 is passed through a coupling capacitor 53 to a signal splitting network 55 which is made up of a balance potentiometer 57 and two fixed resistors 59 and 61.
The portion of the signal that is passed through fixed resistor 61 is split up into two separate paths 63 and 65. The signal travelling along path 63 is passed through a high pass filter 67 to the grid of a triode 72. The filter 67 is made up of a diode 69, a resistor 71 and two capacitors 73 and 75. The purpose of the filter 67 is to cut off certain base frequencies from the signal conducted to the grid of triode 72. The plate of triode 72 is connected to the grid of triode 73 through a coupling capacitor 75 and the plate of triode 73 is connected to the output terminal 76 of the phase shifting circuit 19 through a capacitor 77. Each one of the triodes 72 and 73 includes the standard associated components. Thus, triode 72 includes a grid leak resistor 79, a cathode resistor 81 and a ground 83. Similarly, triode 73 includes a grid leak resistor 85, a cathode resistor 87 and a ground 89. Thus, the signal travelling along path 63 is passed through filter 67 to the grid of triode 73 and the output of triode 73 is applied to the output terminal 75.
The portion of the signal travelling along path 65 is passed through a filter circuit 91 to the grid of a triode 93. The plate of triode 93 is connected to the grid of a triode 95.
The portion of the signal passed through fixed resistor 59 is applied to the grid of a triode 97. The output of triode 97 is applied through a coupling capacitor 99 to the input grid of triode 72. Because the signal applied to the grid of triode 72 has passed through triode 97 it has gone through a 1800 phase reversal. Thus, the two signals applied to the grid of tube 72 are completely out of phase with each other.
Connected to the grid of triode 97 is an inductive circuit 101 whose purpose is to establish the phase slope. The inductive circuit 101 includes a pair of identical variable inductors 103 and 105, a resistor 107, a diode 109, a resistor 111, a capacitor 113 and a ground 115 and is connected to the grid of triode 117.
The supply voltage for the circuit is conducted through a terminal 119 to a filter circuit 121 which filters out any ripple content present in the supply voltage and is then split up into three paths. One path 123 supplies the plate voltage to triode 97 and triode 117 through plate resistors 125 and 127. Another path 129 supplies voltage to bridges 131 and 133.
Bridge 131 is made up of resistors 135, 137, 139,141 and diode 143 and bridge 133 is made up of resistors 145, 147, 149, 151 and diode 153. The output of bridges 105 and 107 at junction 155 is applied to the grid of the tube 117. Junction of bridge 131 is connected to the plate of tube 72. Junction 161 of bridge 133 is connected to the plate of tube 73.
The exciter circuit 19 further includes cathode grounding networks 163 and 165.
Representative values and other information relating to the component parts of phase shifting circuit 19 as designed for application with sounds of speech and music are as follows:
All triodes ........ .. . 6K6112Wa
Inductors 103, 105 .. . . KIP
Resistor 57 . . ....... ..... 20K
All diodes . . . . 1N3484
Capacitors (electrolytic) 201, 202, 203 . . . 50mF/20V 77 .. . . . 10mF/6V 113 .. . 1mF/3V
Capacitors (non-polarized) 25, 53, 211 . . . . .. 0.1mF 213 . . 0.05mF 214 ........ . 0.02mF 215, 217 ....... .. 0.01mF 73,75,76,99 . 0.001mF
Resistors 221, 222 ............................... ....... 15K 127, 223, 224, 225, 228, 231, 233 ....... . 220 ohms 135, 137, 139, 141, 145, 147, 149, 151 . 100K 150 ..... . . . . . 440K 71, 171 ......,...... 10K 79, 179, 85, 185 .. 1M 87, 187, 81 1.5K 191, 111 . 4.5K 107, 108 . . 51K 241 . 8.2K 227, 125 ..220K 61 . . . 220K 59 . 4.7K
An audio plot depicting the frequency dependent phase shift and gain of the exciter circuit 19 of Figure 3 for the values noted above is shown in Figure 4. As can be seen the circuit 19 produces a lincar frequency dependent phase shift of about 360 over a frequency range from about 100 HZ to about 22 KHZ with a gain of between #5DB over a frequency range of about 200 HZ to at least 22 KHZ. The point of zero phase shift is about 2KHZ.
Although it cannot be said with absolute certainty which specific elements in exciter circuit 19 perform which function, a comparison actually performed of the input and output waveforms of a circuit 19 actually constructed and tested has shown that the circuit 19 passes frequencies above a certain level and generates low order, odd and even, phase shifted and amplitude dependent harmonics of the frequencies so passed.
In Figure 5, there is shown in block diagram form an apparatus 400 according to this invention for processing two channels of monaural electrical signals. The apparatus 400 consists essentially of two processing channels, identified as channel 401 and channel 402 and a monitor section 403. The two channels 401 and 402 are essentially identical. In channel 402, a monaural electrical signal from an external source (not shown) is applied to input 420 which is an active transformer. The signal emerging from the input 420 is split into three separate parts. One part is fed into a switching circuit 422 which is connected to a buffer amplifier 423 at the output section 424. When the signal travels along this direct path, it is in the by-pass mode. Output 424 further includes a gain control 425 and an output transformer 426.A second part of the signal is fed into an input switching circuit 427 in the monitor section 403. The third part of the signal is fed into a peak limiter circuit 441 which is made up of a peak limiting control 443, a threshold control 445 and an amplifier 447. The signal emerging from the amplifier 447 is fed into an indicator circuit 451 and also into an exciter circuit 461 (which corresponds to the exciter circuit 19 of Figures 1 and 2). The output from the exciter circuit 461 is fed into an amplifier 463 which restores the signal to a level to compensate for losses occuring in passing through the exciter circuit 461. The output from the amplifier 463 is fed into an attenuator 465 and then into the switching circuit 422 where it feeds into either of the other two modes. In one of these modes a pure excited signal is fed into amplifier 423.In the third mode a mixed signal, that is a pure signal mixed with an attenuated excited signal is fed into amplifier 423. Thus, the signal emerging from output 424 can be selected so as to be either the original pure signal, an excited shifted signal or a mixture of the original signal and an excited signal. Channel 402 further includes a meter switch 467 and a meter amplifier 469 and an indicator 471.
Monitor section 403 further includes output section 473 and level section 475.
In channel 401 elements 520, 522, 523, 524, 525, 526, 541, 543, 545, 547, 551, 561, 563, 565, 567, 569 and 571 correspond to elements 420, 422, 423, 424, 425, 426, 441, 443, 445, 447, 451, 461, 463, 465, 467, 469 and 471 in channel 402.
As can be appreciated, the apparatus 400 can be used in basically any application where either one or two channels of audio information are being processed electronically. The apparatus 400 is particularly useful with sound recording equipment, sound reinforcing equipment and sound reproduction equipment.
In Figure 6 there is shown a solid state version of the exciter circuit 19. The circuit comprises a filter 621, a variable gain amplifier 623 whose output is coupled to the output of the filter 621 and a harmonic creator 625 whose output is coupled to the output of the variable gain amplifier 623.
The filter 621 is a 2-pole slow roll off Butterworth high pass filter and is made up of two capacitors 629 and 631, a pair of resistors 633 and 635 and an operational amplifier 637. The frequencies passed by the filter 621 are fed into the variable gain amplifier 623 which allows the level to the next element, namely the harmonic creator, to be varied. The variable gain amplifier 623 includes an adjustable potentiometer 639 and an operational amplifier 640 and a pair of resistors 641 and 642.
The harmonic creator 625 includes a diode 643, an adjustable potentiometer 645 and an operational amplifier 647 and a resistor 648. The harmonic creator 625 utilizes the voltage to current characteristics of the diode 643 to softly clip the peaks of the incoming signal at a threshold determined by the adjustable potentiometer 645. By clipping the peaks softly only low order harmonics are created. By selecting the proper threshold only transient portions of the signal become clipped. By clipping the signal on one side only both odd and even harmonics are created.
Representative values and other information relating to the component parts of the exciter circuit 19 of Figure 6 as designed for application with sounds of speech and music are as follows:
Element 621 . ....... ....... ....... ........................... 4KHZ, 2 pole,
high pass 629 ................................ ................. .......... ....... . ..... 0.01 f 631 ..... . ........... ........ .. . . ...... .............. ................ 0.01 f 633 ..... . . . . . ..................... .........56K 635 . ........ . . . . . ........................... . ............ 27K 637 ........... ........ ....... . ....... ....... ..................... . . #4131 639 . . ......... ........ . .. . . ...... . . . ........................................ 10K 640..... . ............ ............. ............ ........ ........................... #4558 641 . . . ............ . ...... . . . . ..................... 10K 642 . ........ . . ....... . . ....... ....... ................ .................... 1K 643 ................ ............. . . ........... ............. . .. . .......... . ...... 1N914 645 ............. ....... ........ ....... ......... ............................. 10K 647 .. ................. ............................ . .......... .................... . .. #4558 648 .. . .............. . ....... .......................... ....... . ...... 47K
The transfer function of the harmonic creator 625 for the values above is shown in Figure 7 and the gain and phase of the signal emerging from the filter 621 for the values above is shown in Figure 8.It is believed that the phase change in the signal resulting from passing the signal through the filter produces a directional or "third dimensional" effect in the resulting sound.
It will be understood that various changes in the details, materials, arrangements of parts and operating conditions which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principles and scope of the invention.
WHAT WE CLAIM IS:
1. A method of improving the quality of a signal containing frequencies in the audio frequency spectrum comprising:
(a) Splitting the signal into two signal paths;
(b) passing the signal in one of the paths through a high pass filter designed to shift the
phase of the signal passed in a frequency dependent manner;
(c) passing those frequencies in the output signal of the high pass filter whose
amplitudes are above a preselected level into a harmonic creator, the level of the input to
the harmonic creator varying directly with the level of the output from the high pass
filter;
(d) attenuating all frequencies in the signal emerging from the harmonic creator a
uniform amount to the level of the signal in the outer path; and
(e) combining the attenuated signal containing the harmonics and the fundamental
frequencies from which the harmonics are created with the signal in the other path.
2. The method of claim 1 wherein the preselected level is set to exclude only transients from the harmonic creator.
3. The method of claim 2 wherein the attenuated signal is attenuated to between 20% and 70% of the level of the signal in the other path.
4. The method of any one of claims 1 to 3 wherein the two signals are combined electrically.
5. The method of claims 1 to 3 wherein the two signals are combined acoustically.
6. Apparatus for use in processing a signal containing frequencies in the audio frequency spectrum comprising:
means for dividing said signal into two signal paths; a frequency dependent, phase
shifting, high pass filter disposed along one path for filtering out frequencies in said path
below a particular frequency level;
a harmonic creator;
means coupled between the output of the high pass filter and the input of the harmonic
creator for controlling the input to the harmonic creator in accordance with the amplitude
level of the output signal from the high pass filter;
an attenuator at the output of the harmonic creator for attenuating all frequencies in the
output signal a uniform amount; and
means for combining the signals travelling along each path
7. The apparatus of claim 6 wherein the high pass filter is a 4 KHZ pass filter.
8. The apparatus of claim 6 wherein the high pass filter is designed to pass all frequencies in the audio spectrum down to around 200 HZ.
9. The apparatus of any one of claims 6 to 8 wherein the means coupled between the high pass filter and the harmonic creator is designed to pass to the harmonic creator frequencies in the signal whose amplitudes are above a preselected amplitude and reject
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (17)
1. A method of improving the quality of a signal containing frequencies in the audio frequency spectrum comprising:
(a) Splitting the signal into two signal paths;
(b) passing the signal in one of the paths through a high pass filter designed to shift the
phase of the signal passed in a frequency dependent manner;
(c) passing those frequencies in the output signal of the high pass filter whose
amplitudes are above a preselected level into a harmonic creator, the level of the input to
the harmonic creator varying directly with the level of the output from the high pass
filter;
(d) attenuating all frequencies in the signal emerging from the harmonic creator a
uniform amount to the level of the signal in the outer path; and
(e) combining the attenuated signal containing the harmonics and the fundamental
frequencies from which the harmonics are created with the signal in the other path.
2. The method of claim 1 wherein the preselected level is set to exclude only transients from the harmonic creator.
3. The method of claim 2 wherein the attenuated signal is attenuated to between 20% and 70% of the level of the signal in the other path.
4. The method of any one of claims 1 to 3 wherein the two signals are combined electrically.
5. The method of claims 1 to 3 wherein the two signals are combined acoustically.
6. Apparatus for use in processing a signal containing frequencies in the audio frequency spectrum comprising:
means for dividing said signal into two signal paths; a frequency dependent, phase
shifting, high pass filter disposed along one path for filtering out frequencies in said path
below a particular frequency level;
a harmonic creator;
means coupled between the output of the high pass filter and the input of the harmonic
creator for controlling the input to the harmonic creator in accordance with the amplitude
level of the output signal from the high pass filter;
an attenuator at the output of the harmonic creator for attenuating all frequencies in the
output signal a uniform amount; and
means for combining the signals travelling along each path
7. The apparatus of claim 6 wherein the high pass filter is a 4 KHZ pass filter.
8. The apparatus of claim 6 wherein the high pass filter is designed to pass all frequencies in the audio spectrum down to around 200 HZ.
9. The apparatus of any one of claims 6 to 8 wherein the means coupled between the high pass filter and the harmonic creator is designed to pass to the harmonic creator frequencies in the signal whose amplitudes are above a preselected amplitude and reject
frequencies whose amplitudes are below said preselected amplitude.
10. The apparatus of any one of claims 6 to 8 wherein the means coupled between the output of the high pass filter and the harmonic creator is a variable gain amplifier.
11. The apparatus of any one of claims 6 to 10 wherein the means for combining the two signals are separate transducers.
12. The apparatus of claim 11 wherein the variable gain amplifier includes an adjustable potentiometer, an operational amplifier and a pair of resistors.
13. The apparatus of any one of claims 6 to 10 wherein the means for combining the two signals is a single transducer.
14. The apparatus of any one of claims 6 to 13 wherein the harmonic creator is designed to generate odd and even harmonics.
15. Apparatus as claimed in any one of claims 6 to 14 comprising means for converting sounds of music and speech into said signal containing frequencies in the audio frequency spectrum.
16. A method of improving the quality of a signal containing frequencies from the audio frequency spectrum substantially as hereinbefore described with reference to the accompanying drawings.
17. Apparatus for use in processing a signal containing frequencies from the audio frequency spectrum substantially as hereinbefore described with reference to and as iH > ustrated in Figures 3 to 8 in combination with either Figure 1 or Figure 2 of the accompanying drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US66711576A | 1976-03-15 | 1976-03-15 | |
| US05/762,403 US4150253A (en) | 1976-03-15 | 1977-01-26 | Signal distortion circuit and method of use |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1579571A true GB1579571A (en) | 1980-11-19 |
Family
ID=27099613
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1084877A Expired GB1579571A (en) | 1976-03-15 | 1977-03-15 | Signal processing method and apparatus |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS6049918B2 (en) |
| CA (1) | CA1091163A (en) |
| DE (1) | DE2711083A1 (en) |
| FR (1) | FR2357970A1 (en) |
| GB (1) | GB1579571A (en) |
| NL (1) | NL7702723A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2177576A (en) * | 1985-06-07 | 1987-01-21 | Dynavector Inc | Multi-channel reproducing system |
| WO2002047259A1 (en) * | 2000-12-05 | 2002-06-13 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and arrangement relating to electronic compensation |
| EP1225788A3 (en) * | 2001-01-17 | 2008-10-01 | Grundig Multimedia B.V. | Acoustic transducer device with adjustment of individual caracteristic of hearing |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56115189U (en) * | 1980-02-01 | 1981-09-04 | ||
| DE3904425A1 (en) * | 1989-02-14 | 1990-08-16 | Ulrich Dipl Ing Behringer | METHOD AND DEVICE FOR PROCESSING SOUND |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3127476A (en) * | 1964-03-31 | david | ||
| US2852604A (en) * | 1954-08-05 | 1958-09-16 | Richard H Maccutcheon | Sound reproduction apparatus |
| US2866849A (en) * | 1955-04-27 | 1958-12-30 | Leo C Krazinski | Apparatus for improving sounds of music and speech |
| US2953644A (en) * | 1956-10-04 | 1960-09-20 | Bell Telephone Labor Inc | Wave transmission system |
| US3219757A (en) * | 1962-08-06 | 1965-11-23 | Gen Electric | Sound reproduction from monaural information |
| US3560656A (en) * | 1967-05-01 | 1971-02-02 | Dictaphone Corp | Binaural phase differential system |
| US3591699A (en) * | 1968-03-28 | 1971-07-06 | Royce L Cutler | Music voicing circuit deriving an input from a conventional musical instrument and providing voiced musical tones utilizing the fundamental tones from the conventional musical instrument |
| US3544694A (en) * | 1969-03-17 | 1970-12-01 | William A Freeman | Pickup and waveforming circuitry for electronic musical instrument |
| CA942198A (en) * | 1970-09-15 | 1974-02-19 | Kazuho Ohta | Multidimensional stereophonic reproducing system |
| US3723633A (en) * | 1971-06-16 | 1973-03-27 | Nippon Musical Instruments Mfg | Bass tone producing device for an electronic musical instrument |
| US3828133A (en) * | 1971-09-23 | 1974-08-06 | Kokusai Denshin Denwa Co Ltd | Speech quality improving system utilizing the generation of higher harmonic components |
| US3819861A (en) * | 1972-11-24 | 1974-06-25 | Bell Telephone Labor Inc | Sound enhancing system for musical instruments |
| US3890466A (en) * | 1973-02-01 | 1975-06-17 | Cbs Inc | Encoders for quadraphonic sound system |
-
1977
- 1977-03-14 DE DE19772711083 patent/DE2711083A1/en active Granted
- 1977-03-14 CA CA273,908A patent/CA1091163A/en not_active Expired
- 1977-03-14 NL NL7702723A patent/NL7702723A/en not_active Application Discontinuation
- 1977-03-15 GB GB1084877A patent/GB1579571A/en not_active Expired
- 1977-03-15 JP JP52028524A patent/JPS6049918B2/en not_active Expired
- 1977-03-15 FR FR7707662A patent/FR2357970A1/en active Granted
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2177576A (en) * | 1985-06-07 | 1987-01-21 | Dynavector Inc | Multi-channel reproducing system |
| US4873722A (en) * | 1985-06-07 | 1989-10-10 | Dynavector, Inc. | Multi-channel reproducing system |
| WO2002047259A1 (en) * | 2000-12-05 | 2002-06-13 | Telefonaktiebolaget Lm Ericsson (Publ) | Method and arrangement relating to electronic compensation |
| US6982595B2 (en) | 2000-12-05 | 2006-01-03 | Telefonaktiebolaget L M Ericsson (Publ) | Method and arrangement relating to electronic compensation |
| EP1225788A3 (en) * | 2001-01-17 | 2008-10-01 | Grundig Multimedia B.V. | Acoustic transducer device with adjustment of individual caracteristic of hearing |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6049918B2 (en) | 1985-11-05 |
| NL7702723A (en) | 1977-09-19 |
| FR2357970B1 (en) | 1983-09-30 |
| FR2357970A1 (en) | 1978-02-03 |
| JPS52131701A (en) | 1977-11-04 |
| CA1091163A (en) | 1980-12-09 |
| DE2711083C2 (en) | 1987-08-27 |
| DE2711083A1 (en) | 1977-11-10 |
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