PROCESSING AN AUDIO INPUT SIGNAL TO PRODUCE A PROCESSED AUDIO OUTPUT SIGNAL

Abstract

An audio input signal is processed to produce a processed audio output signal. An audio input signal is received as an original signal. The audio input signal is dynamically filtered to produce a first stage signal consisting of a selected frequency band of the input signal. Gain applied to the first stage signal is dynamically controlled in response to a control signal to produce a second stage signal. The control signal is derived from the first stage signal. Processing the original signal in combination with the second stage signal to produce a processed audio output signal. Processing the original signal in combination with the second stage signal and the first stage signal to produce a processed audio output signal.

Description

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows an environment in which audio signals are processed;

FIG. 2 illustrates the digital mixing desk identified in FIG. 1;

FIG. 3 illustrates operations performed in the mixing desk of FIG. 2;

FIG. 4 details the channel processing system identified in FIG. 3;

FIG. 5 illustrates the first embodiment of the present invention;

FIG. 6 illustrates a second embodiment of the present invention;

FIG. 7 illustrates a preferred approach for deploying the functionality of the circuit illustrated in FIG. 6;

FIG. 8 shows a third embodiment of the present invention; and

FIG. 9 shows an alternative arrangement of FIG. 8.

Claims

1. A method of processing an audio input signal to produce a processed audio output signal, comprising the steps of: receiving an audio input signal as an original signal;dynamically filtering said audio input signal to produce a first stage signal of a selected frequency band of said audio input signal;dynamically controlling gain applied to said first stage signal in response to a control signal to produce a second stage signal;deriving said control signal from said first stage signal; andprocessing said original signal in combination with said second stage signal to produce said processed audio output signal.

2. A method according to claim 1, wherein said original signal is processed in combination with said second stage signal by adding said second stage signal to said original signal.

3. A method according to claim 1, wherein said original signal is processed in combination with said second stage signal by subtracting said second stage signal from said original signal.

4. A method according to claim 1, wherein said original signal is processed in combination with said second stage signal and said first stage signal to produce said processed output signal.

5. A method according to claim 4, wherein said original signal is processed in combination with said second stage signal and said first stage signal by: subtracting said first stage signal from said original signal to produce a third stage signal, andadding said third stage signal to said second stage signal.

6. A method according to claim 1, wherein: the audio input signal is one of: a live signal anda recorded signal, andthe processed output signal is one of: recorded as an audio signal only, recorded in combination with a video signal andtransmitted as one of: a radio broadcast anda television broadcast.

7. A method according to claim 1, wherein the audio input signal is dynamically filtered by attenuating frequency components that are below said selected frequency band and attenuating frequency components that are above said selected frequency band.

8. A method according to claim 1, wherein a location of said selected frequency band in a frequency spectrum is manually adjustable.

9. A method according to claim 8, wherein an operator manually adjusts the location of said selected frequency band while listening to said first stage signal, so as to optimise performance by maximising the first stage signal.

10. A method according to claim 1, wherein the level of said derived control signal is manually adjustable.

11. A method according to claim 1, wherein the filtering step and the gain control step are executed by digital signal processing systems operating in real-time.

12. Audio signal processing apparatus for processing an audio input signal to produce a processed audio output signal, comprising. a dynamic filter configured to pass a selected frequency band of a received input signal;a dynamic gain control configured to control gain of a signal in response to a control signal; anda processor configured to process signals in combination to produce a processed output signal, whereinsaid apparatus is arranged to receive an audio input signal as an original signal,said dynamic filter is arranged to filter said audio input signal to produce a first stage signal of a selected frequency band of said audio input signal;said dynamic gain control is arranged to control the gain applied to said first stage signal to produce a second stage signal;the control signal for the dynamic gain control is also derived from said first stage signal; andsaid processor is arranged to process said original signal in combination with said second stage signal to produce a processed audio output signal.

13. Audio signal processing apparatus according to claim 12, wherein said processor is arranged to process said original signal in combination with said second stage signal and said first stage signal.

14. Audio signal processing apparatus according to claim 12, wherein said dynamic filter includes a low pass component and a high pass component in order to pass said selected frequency band.

15. Audio signal processing apparatus according to claim 12, wherein said dynamic filter and said dynamic gain control are constructed from digital signal processing systems operating in real-time.

16. A computer-readable medium having computer-readable instructions executable by a computer such that, when executing said instructions, a computer will perform the steps of: receiving an audio input signal as an original signal;dynamically filtering said audio input signal to produce a first stage signal of a selected frequency band of said audio input signal;dynamically controlling gain applied to said first stage signal in response to a control signal to produce a second stage signal;deriving said control signal from said first stage signal; andprocessing said original signal in combination with said second stage signal to produce a processed audio output signal.

17. A computer-readable medium according to claim 16, wherein said wherein said original signal is processed in combination with said second stage signal and said first stage signal to produce said processed output signal.

18. A computer-readable medium according to claim 16, wherein a computer executing said instructions will allow a location of said selected frequency band in a frequency spectrum to be adjusted manually.

19. A computer-readable medium having computer-readable instructions according to claim 18, wherein, when executing said instructions said computer is responsive to manual adjustments made by an operator such that said operator optimises performance by maximising the first stage signal.

20. A computer-readable medium according to claim 16, wherein a computer executing said instructions is configured such that the level of said derived control signal is manually adjustable.

21. A computer-readable medium according to claim 16, wherein when executing said instructions a computer will process said original signal in combination with said second stage signal by adding the second stage signal to the original signal.

22. A computer-readable medium according to claim 16, wherein when executing said instructions a computer will process said original signal in combination with said second stage signal by subtracting the second stage signal from the original signal.