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Re: System Mute Problem
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Re: System Mute Problem


  • Subject: Re: System Mute Problem
  • From: Jeff Moore <email@hidden>
  • Date: Mon, 09 Feb 2009 11:58:37 -0800

Does this device work properly with Audio MIDI Setup (in /Applications/ Utilities) and/or HALLab (in /Developer/Applications/Audio)?

On Feb 9, 2009, at 11:24 AM, Gordon Rankin wrote:

I am not sure if this is core audio or USB...

Anyways, I designed a USB Digital to Analog converter which has system wide volume for Left and Right as well as system mute. As seen in the enumeration below:

         Audio Class Specific Feature                 Unit ID:   7
             Source ID:   5
             Control Size:   2
             Number of Channels (ch):   2
                 Master Channel:......................... ( Mute )
                 Left Front:............................. ( Volume )
                 Right Front:............................ ( Volume )
             Feature Unit Name String Index:   0

~~~~~~

The volume works fine but in the System Preference if you check the Mute box only the Left channel is effected as whatever controls this action is taking a snapshot of the present volume and then setting it to zero to mute it. But is only doing this to the left channel.

In other words the mute is not being acted on at all but merely the volume is used as the mute and it is broken because it is only doing the left channel and not the right channel.

All other operations are working fine. Volume, Balance etc... all work fine.

This works fine in all other operating systems.



--

Jeff Moore
Core Audio
Apple


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References: 
 >System Mute Problem (From: Gordon Rankin <email@hidden>)

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