WO1982000539A1 - Audio reverberation circuit - Google Patents

Audio reverberation circuit Download PDF

Info

Publication number
WO1982000539A1
WO1982000539A1 PCT/AU1981/000100 AU8100100W WO8200539A1 WO 1982000539 A1 WO1982000539 A1 WO 1982000539A1 AU 8100100 W AU8100100 W AU 8100100W WO 8200539 A1 WO8200539 A1 WO 8200539A1
Authority
WO
WIPO (PCT)
Prior art keywords
circuit according
time delay
reverberation
reverberation circuit
flanger
Prior art date
Application number
PCT/AU1981/000100
Other languages
French (fr)
Inventor
R Lawson
Original Assignee
R Lawson
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 R Lawson filed Critical R Lawson
Publication of WO1982000539A1 publication Critical patent/WO1982000539A1/en

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Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10H—ELECTROPHONIC MUSICAL INSTRUMENTS; INSTRUMENTS IN WHICH THE TONES ARE GENERATED BY ELECTROMECHANICAL MEANS OR ELECTRONIC GENERATORS, OR IN WHICH THE TONES ARE SYNTHESISED FROM A DATA STORE
    • G10H1/00—Details of electrophonic musical instruments
    • G10H1/02—Means for controlling the tone frequencies, e.g. attack or decay; Means for producing special musical effects, e.g. vibratos or glissandos
    • G10H1/06—Circuits for establishing the harmonic content of tones, or other arrangements for changing the tone colour
    • G10H1/08—Circuits for establishing the harmonic content of tones, or other arrangements for changing the tone colour by combining tones

Definitions

  • the invention relates to audio reverberation circuits as used for treating audio signals to include the effect of a sound reverberating within an enclosure such as a room with reflective surfaces.
  • Frequency spectrum notching is produced when differently delayed versions of a signal are mixed together.
  • the object of the invention is to remove this frequency spectrum notching
  • frequency spectrum colouration is cancelled by combining the colouration of additive mixing with the opposite colouration of subtractive mixing.
  • a reverberator may consist of a flanger and a differential flanger (comple te specification no. 46155/79) connected in series or parallel and both having a common controlling means.
  • a single time delay device may be used to provide both flanging and differential flanging for parallel connection.
  • a reverberator with cancelled colouration may consist of a positive feedback time delay circuit combined with a negative feedback time delay circuit.
  • Figure 1 shows a reverberation circuit in which both positive feedback and negative feedback circuits are connected around a single time delay device.
  • Part A is the input.
  • Part B is a low pass filter.
  • Parts C, D, E,and F are buffers.
  • Part G is a time delay device.
  • Part H is an amplifier.
  • Part I is an inverting amplifier. Parts H and I have common level control for identical output levels. This common level control determines the feedback level.
  • Part J is a buffer.
  • Part K is the level control for the undelayed signal.
  • Part L is the level control for the reverberant signal.
  • Part M is a low pass filter.
  • Part K is the output.

Abstract

Audio reverberation circuits in which frequency spectrum colouration is cancelled by combining circuits of opposite colouration (EGH and FGI). Different channels having different time delays are matched in their phase shift characteristics.

Description

AUDIO REVERBERATION CIRCUIT.
The invention relates to audio reverberation circuits as used for treating audio signals to include the effect of a sound reverberating within an enclosure such as a room with reflective surfaces. Frequency spectrum notching is produced when differently delayed versions of a signal are mixed together. The object of the invention is to remove this frequency spectrum notching
When two differently delayed versions of a signal are added, the frequency spectrum notches are at the same frequencies as the peaks would be if the two versions were subtracted.
According to the invention, frequency spectrum colouration is cancelled by combining the colouration of additive mixing with the opposite colouration of subtractive mixing. such a reverberator may consist of a flanger and a differential flanger (comple te specification no. 46155/79) connected in series or parallel and both having a common controlling means. A single time delay device may be used to provide both flanging and differential flanging for parallel connection.
Alternatively, a reverberator with cancelled colouration may consist of a positive feedback time delay circuit combined with a negative feedback time delay circuit. Figure 1 shows a reverberation circuit in which both positive feedback and negative feedback circuits are connected around a single time delay device. Part A is the input. Part B is a low pass filter. Parts C, D, E,and F are buffers. Part G is a time delay device. Part H is an amplifier. Part I is an inverting amplifier. Parts H and I have common level control for identical output levels. This common level control determines the feedback level. Part J is a buffer. Part K is the level control for the undelayed signal. Part L is the level control for the reverberant signal. Part M is a low pass filter. Part K is the output.
means is also provided whereby such reverberation circuits are designed so that the difference between the times of arrival at the place of mixing of differently delayed signals is the same for all frequencies.

Claims

The claims defining the invention are as follows Claim 1. A reverberation circuit in which frequency spectrum colouration is cancelled by combining circuits of opposite colouration.
Claim 2. A reverberation circuit according to Claim 1 in which a flanger and a differential flanger are combined in series or parallel with common controlling means.
Claim 3. A reverberation circuit according to Claim 2 having switching to select the circuit configurations of Complete specification no. 46155/79.
Claim 4. A reverberation circuit according to Claim 1 in which a time delay circuit having positive feedback is combined in series or parallel with a time delay circuit having negative feedback.
Claim 5. A reverberation circuit according to claim 1 in which a flanger and a differential flanger are configured around a single time delay device.
Claim 6. A reverberation circuit according to Claim 1 in which positive feedback and negative feedback circuits are configured around a single time delay device.
Claim 7. A reverberation circuit according to Claim 1 in which the difference between the times of arrival of differently delayed signals at the place of mixing is the same for all frequencies.
PCT/AU1981/000100 1980-07-29 1981-07-29 Audio reverberation circuit WO1982000539A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU4733/80800729 1980-07-29
AU473380 1980-07-29

Publications (1)

Publication Number Publication Date
WO1982000539A1 true WO1982000539A1 (en) 1982-02-18

Family

ID=3695199

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU1981/000100 WO1982000539A1 (en) 1980-07-29 1981-07-29 Audio reverberation circuit

Country Status (1)

Country Link
WO (1) WO1982000539A1 (en)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU310289A1 (en) * А. В. Бубнов MANIPULATOR FOR ELECTROMUSICAL TOOLS
US1947621A (en) * 1932-06-14 1934-02-20 American Telephone & Telegraph Reverberation circuit
US2493638A (en) * 1946-06-22 1950-01-03 Rca Corp Synthetic reverberation system
US2872515A (en) * 1954-09-02 1959-02-03 Columbia Broadcasting Syst Inc Synthetic reverberation system
US3200199A (en) * 1961-08-28 1965-08-10 Gen Electric Stereophonic reverberation circuit
US3288931A (en) * 1965-07-30 1966-11-29 Baldwin Co D H Tapered spring reverberation delay line drive apparatus
AU4615579A (en) * 1978-04-19 1979-10-25 Richard Lawson Pure musical phase circuit
DE3015357A1 (en) * 1979-04-24 1981-02-12 Philips Nv DEVICE FOR ARTIFICIAL REVERB
DE3015324A1 (en) * 1979-04-24 1981-03-26 N.V. Philips' Gloeilampenfabrieken, Eindhoven DEVICE FOR ARTIFICIAL REVERB

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU310289A1 (en) * А. В. Бубнов MANIPULATOR FOR ELECTROMUSICAL TOOLS
US1947621A (en) * 1932-06-14 1934-02-20 American Telephone & Telegraph Reverberation circuit
US2493638A (en) * 1946-06-22 1950-01-03 Rca Corp Synthetic reverberation system
US2872515A (en) * 1954-09-02 1959-02-03 Columbia Broadcasting Syst Inc Synthetic reverberation system
US3200199A (en) * 1961-08-28 1965-08-10 Gen Electric Stereophonic reverberation circuit
US3288931A (en) * 1965-07-30 1966-11-29 Baldwin Co D H Tapered spring reverberation delay line drive apparatus
AU4615579A (en) * 1978-04-19 1979-10-25 Richard Lawson Pure musical phase circuit
DE3015357A1 (en) * 1979-04-24 1981-02-12 Philips Nv DEVICE FOR ARTIFICIAL REVERB
DE3015324A1 (en) * 1979-04-24 1981-03-26 N.V. Philips' Gloeilampenfabrieken, Eindhoven DEVICE FOR ARTIFICIAL REVERB

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