Volume control for audio signals

Abstract

A motion picture soundtrack reproduction system has a center front soundtrack channel and a plurality of other soundtrack channels. A volume control adjusts the gain of all the channels. The volume control has a range of settings from a minimum to a maximum, the gain of the center front channel having substantially a first relationship to the volume control settings and the gain of the other channels having substantially a second relationship to the volume control settings, the relationships being such that for a range of volume control settings less than a first setting the gain of the center front channel remains substantially constant while the gain of the other channels decreases as the setting decreases or decreases more gradually than the gain of the other channels as the setting decreases.

The invention claimed is: 
     
       1. A motion picture soundtrack reproduction system, the system having a center front soundtrack channel and a plurality of other soundtrack channels, comprising:
 a controller having a volume control for adjusting the a gain of all the channels for the center front channel and a gain for the plurality of other channels, the volume control having a range of settings from a minimum to a maximum, the controller having a first output for controlling the gain of the center front channel and a second output for controlling the gain of the plurality of other channels in response to settings of the volume control, the gain of the center front channel having a first relationship to the volume control settings and the gain of the plurality of other channels having a second relationship to the volume control settings, the first relationship and the second relationships being such that for a range of volume control settings less than a first setting the gain of the center front channel (1) remains substantially constant while the gain of the plurality of other channels decreases as the a volume control setting decreases below said first setting, or (2) decreases more gradually than the gain of the plurality of other channels as the volume control setting decreases below said first setting. 
 
     
     
       2. A motion picture soundtrack reproduction system, comprising:
 a center front soundtrack channel and a plurality of other soundtrack channels, each of said channels having adjustable gain and feeding one or more loudspeakers, and 
 a controller having a volume control for adjusting the gain of all the channels a gain for the center front channel and a gain for the plurality of other channels, the volume control having a range of settings from a minimum to a maximum, the controller having a first output for controlling the gain of the center front channel and a second output for controlling the gain of the plurality of other channels in response to settings of the volume control the gain of the center front channel having a first relationship to the volume control settings and the gain of the plurality of other channels having a second relationship to the volume control settings, the first relationship and the second relationships relationship being such that for a range of volume control settings less than a first setting the gain of the center front channel (1) remains substantially constant while the gain of the plurality of other channels decreases as the a volume control setting decreases below said first setting or (2) decreases more gradually than the gain of the plurality of other channels as the volume control setting decreases below said first setting. 
 
     
     
       3. A system according to  claim 1  or  claim 2  wherein the range of volume control settings less than said first setting extends down to the minimum volume control setting. 
     
     
       4. A system according to  claim 1  or  claim 2  wherein the range of volume control settings less than said first setting extends down to a second setting above the minimum volume control setting. 
     
     
       5. A system according to claim  3  4 wherein for volume control settings less than said second setting the gains of all the channels decrease in substantially the same way gain of the center front channel and the gain for the plurality of other channels are attenuated equally as the volume control setting decreases below said second setting and for such volume control settings the gain of the center front channel is greater than the gain of the plurality of other channels. 
     
     
       6. A system according to  claim 5  wherein for volume control settings less than said second setting the gain of the center front channel is greater than the gain of the plurality of other channels by a substantially constant amount in the logarithmic domain. 
     
     
       7. A system according to  claims 1  wherein for volume control settings greater than said first setting the gains of all the channels gain for the center front channel and the gain for the plurality of other channels increase as the volume control setting increases above said first setting and for each of such volume control settings the gain of the center front channel and the gain of the plurality of other channels are substantially the same. 
     
     
       8. A system according to  claims 1  wherein when the volume control is set to a standard setting, each of the center front channel and the plurality of other channels has a respective gain that produces a respective standard acoustic level in response to a signal having a respective standard reference level in the channel. 
     
     
       9. A system according to  claim 8  wherein said first setting is about said standard setting. 
     
     
       10. An audio system comprising:
 a first channel, a gain of the first channel adjustable by a controller;   a second channel, a gain of the second channel adjustable by the controller; and   the controller including:
 a volume control having a first range of settings from a minimum to a maximum; 
 a first output controlling the gain of the first channel in response to a setting of the volume control; and 
 a second output controlling the gain of the second channel in response to the setting of the volume control, 
   wherein a decrease in the setting of the volume control both decreases loudness of the system and increases a proportionate contribution of the first channel to the loudness.   
     
     
       11. A system of claim 10 wherein the second output further controls a gain for a third channel in response to the setting of the volume control. 
     
     
       12. A system of claim 10 further comprising at least one loudspeaker. 
     
     
       13. A system of claim 10 further comprising surround outputs. 
     
     
       14. An audio reproduction system comprising:
 a first channel, a gain of the first channel adjustable by a controller;   a second channel, a gain of the second channel adjustable by the controller; and   the controller including:
 a volume control having a first range of settings from a minimum to a maximum; 
 a first output for controlling the gain of the first channel in response to a setting of the volume control; and 
 a second output for controlling the gain of the second channel in response to the setting of the volume control, 
   wherein the gain of the second channel decreases more than the gain of the first channel in relationship with a decrease in the setting of the volume control over a second range, the second range being smaller than the first range.   
     
     
       15. A system of claim 14 wherein the second output further controls a gain for a third channel in response to the setting of the volume control, and the gain of the third channel decreases more than the gain of the first channel in relationship with the decrease in the setting of the volume control over the second range. 
     
     
       16. An audio system comprising
 a first channel and a second channel, each of said channels having a gain; and   a controller having a volume control for adjusting the gain of the first channel and the gain of the second channel, the volume control having a range of settings from a minimum to a maximum, the gain of the first channel having a first relationship to the volume control settings and the gain of the second channel having a second relationship to the volume control settings, the relationships being such that for a range of volume control settings less than a first setting the gain of the first channel (1) remains constant while the gain of the second channel decreases as the volume control setting decreases below said first setting or (2) decreases more gradually than the gain of the second channel as the volume control setting decreases below said first setting.   
     
     
       17. A system according to claim 16 wherein the range of volume control settings less than said first setting extends down to the minimum control setting. 
     
     
       18. A system according to claim 16 wherein the range of volume control settings less than said first setting extends down to a second setting above the minimum volume control setting. 
     
     
       19. A system according to claim 18 wherein for volume control settings less than said second setting the gains of the first and second channels are attenuated equally as the volume control setting decreases below said second setting and for such volume control settings the gain of the first channel is greater than the gain of the second channel. 
     
     
       20. A system according to claim 19 wherein for volume control settings less than said second setting the gain of the first channel is greater than the gain of the second channel by a constant amount in the logarithmic domain. 
     
     
       21. A system according to claim 16 further comprising left, right and surround outputs.