DYNAMIC VOLUME CONTROL AND MULTI-SPATIAL PROCESSING PROTECTION

• US 20130108055A1
• Filed: 10/16/2012
• Published: 05/02/2013
• Est. Priority Date: 11/14/2008
• Status: Active Grant

• Current Assignee: THAT Corporation
• Original Assignee: THAT Corporation
• Inventors: Hanna, Christopher M., Benulis, Gregory
• Granted Patent: US 9,584,918 B2
• Time in Patent Office: Days
• US Class Current: 381/17
• CPC Class Codes: H03G 3/3005 in amplifiers suitable for low-frequencies, e.g. audio amplifiers H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H03G 3/3089 Control of digital or coded signals
• CPC Class Codes: H03G 3/341 Muting when no signals or only weak signals are present H03G3/344, H03G3/345 take precedence
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems
• CPC Class Codes: H04R 3/007 Protection circuits for transducers
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S
• CPC Class Codes: H04S 1/00 Two-channel systems H04S5/00, H04S7/00 take precedence

Abstract

A disclosed system and method dynamically controls the perceived volume of a stereo audio program including left and right channel signals. The system comprises: a dynamic volume control configured and arranged so as to maintain a perceived constant volume level of the stereo audio program; and an excessive spatial processing protection processor configured and arranged for controlling the level of a difference signal, created as a function of the right channel signal subtracted from the left channel signal (L−R), relative to the level of a sum signal, created as a function of the right channel signal plus the left channel signal;; wherein the excessive spatial processing protection processor processes the audio signals so as to control the difference (L−R) signal relative to the sum (L+R) signal. A system and method are also provided for dynamically controlling the perceived volume of a stereo audio program including left and right channel signals, comprising: a dynamic volume control configured and arranged so as to maintain a perceived constant volume level of the stereo audio program; and a program change detector configured and arranged to provide a program change signal indicating that the volume of the left and right channel signals has dropped below a threshold level for at least a threshold time period so as to anticipate a possible change in the sound level of the left and right channel signals; wherein the dynamic volume control is responsive to the program change signal.

Claims

1. A system for dynamically controlling the perceived volume of a stereo audio program including left and right channel signals, comprising:

a dynamic volume control configured and arranged so as to maintain a perceived constant volume level of the stereo audio program; and

an excessive spatial processing protection processor configured and arranged for controlling the level of a difference signal, created as a function of the right channel signal subtracted from the left channel signal (L−

R), relative to the level of a sum signal, created as a function of the right channel signal plus the left channel signal;

wherein the excessive spatial processing protection processor processes the audio signals so as to control the difference (L−

R) signal relative to the sum (L+R) signal.

2. A system according to claim 1, wherein the excessive spatial processing protection processor is connected in series with the dynamic volume control.

3. A system according to claim 2, wherein the excessive spatial processing protection processor is cascaded in front of dynamic volume control so as to control the difference (L−

R) signal enhancement relative to the sum (L+R) signal first, then maintaining the perceived constant level of the stereo audio program with the dynamic volume control without an inordinate amount of ambient difference energy being present.

5. A system according to claim 1, wherein the dynamic volume control includes a signal level sensor for sensing the average level of the sum of the left and right channel signal levels;

and a signal averaging block configured and arranged for providing an attack time and a release time resulting in signal compression in accordance with a compression ratio, wherein the dynamic volume control is responsive to one or more of the following;

a target level signal representative of the desired volume level of the sum of the left and right channel levels, wherein a difference signal is representative of the difference between the sensed average level and the target level signal;

an attack threshold signal representative of the number of dB of the difference signal must be above a set point before the attack time is increased by a factor of N;

a release threshold signal represents the number of dB of the difference signal must be below a set point before the release time is increased by a factor of M;

an attack ratio threshold signal representative of the absolute amount, in dB, that a difference signal can go above a set point before the dynamic volume control begins attenuating the left and right channel signals;

a release ratio threshold signal representative of the absolute amount, in dB, that the difference signal can go below a set point before the dynamic volume control begins adding gain to the left and right channel signals; and

a ratio signal for adjusting the sensed average level by a desired compression ratio.

6. A system according to claim 1, wherein N and M are each 10.

4. A system according to claiml, wherein the excessive spatial processing protection processor is in a feedback path of the dynamic volume control

7. A method of dynamically controlling the perceived volume of a stereo audio program including left and right channel signals, comprising:

dynamic controlling the volume level of a stereo audio program so as to maintain the volume level at a perceived constant volume level; and

controlling the level of a difference signal created as a function of the right channel signal subtracted from the left channel signal (L−

R), relative to a sum signal created as a function of the right channel signal added to the left channel signal.

wherein controlling includes processing the audio signals so as to control difference (L−

R) signal enhancement relative to the sum signal (L+R).

8. A system for dynamically controlling the perceived volume of a stereo audio program including left and right channel signals, comprising:

an excessive spatial processing protection processor configured and arranged for controlling the level of a difference signal created from subtracting the right channel signal from the left channel signal (L−

R), and

a contour filter for shaping the difference signal.

9. A system according to claim 8, further including a contour filter for shaping of a sum signal created by adding the right channel signal to the left channel signal (L+R).

10. A system according to claim 8, where the contour filter is selected to compensate for a predetermined spatial processing technique, where said technique is determined through an analysis that includes the difference (L−

R) signal.

11. A system according to claim 8, where the contour filter is selected to compensate for a predetermined spatial processing technique, where said technique is determined through an analysis that includes the sum (L+R) signal.