digital audio 2 input - external clock sync

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Level 1

9 points

digital audio 2 input - external clock sync

On my computer only a "default" setting/selection option is available in the Audio MIDI utility for the "clock" function. There are no setting options presented in the drop down selection menu to allow positive selection of the internal computer clock or alternately the external clock derived from audio stream coming from my analog to digital converter. I have enabled sync in the past as it is the only way to get rid of the awful audio distortion that occurs when the external clock drifts out of sync from the computer's clock that is being used to stream onward the audio. The previously streamed files played back from the computer hard drive exhibits no indication of the distortion that periodically occurs as the clocks drift out of sync.

Might there be some advice on the possible corruption of a pst or preference file, or something else that might be causing non access to the clock setting options? Is apple or anybody informed to advise how to restore availability of the external clock sync capability?

Powermac G5, Mac OS X (10.4.9), streamed digital audio distorts lacking option to sync external clock

Posted on May 6, 2007 8:29 AM

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Answer 1

Mark Bailey2 Author

Level 1

9 points

May 9, 2007 2:38 PM in response to Mark Bailey2

The problem referenced in the posting can be resolved by a hack, on account of what appears to be a bug in the AudioMIDI utility program. There are two audio inputs, one is analog and one is digital. When using the (optical) digital input only a "default" setting is offered regarding the source clock. This input is identified as the "Built-in Audio 2". Otherwise the analog input is identified as simply "Built-in Audio". Inexplicabily, the analog input is provided with a drop down menu allowing selection of either "external clock" or the computer's "internal clock". Of course this make no sense for an analog input which should always utilize the internal clock. The "Built-in Audio" analog input should be provided only the "default" (internal clock) setting.

Interestingly, if you select the analog input "Built-in Audio" and then choose the "external clock" option and then subsequently choose "Built-in Audio 2", the optical digital input you can actually achieve control over whether the internal or external clock is used. Thus, until Apple fixes this, be sure to select the clock relative to the analog input and then choose the digital input as the source. No points for answering my own question!

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