Problems with Mac mini's optical digital input into Max

Mar 26, 2009 at 10:42am

Problems with Mac mini's optical digital input into Max

Hi,

I am trying to get a digital stereo audio signal from one Mac mini into Max 5 running on a second Mac mini. The mini’s are running OSX 10.5.6.
I am using a TOSLINK cable with mini-TOSLINK jacks to connect the two Mac mini’s, plugging into the combined optical digital audio output on the output Mac and plugging into the combined optical digital audio input on the Mac that is running Max 5.
On both the Macs I have tried all the possible matching “Audio Input” and “Audio Output” settings (sample and bit rates) in the Audio MIDI Setup window for the “Digital in” and “Digital out” sources.
Max properly switches to Digital In and to the right Sampling Rate and starts playing the input signal correctly, but a persistent problem starts distorting the input signal after a variable amount of seconds (+/- 20 secs) after turning on the audio.
It sounds like a sync issue: a buildup of delicate ticks into a noise layer over the input signal. I attached a recording of the noise building up.
The issue temporarily disappears when the dsp is turned on and off, returning again after some tens of seconds. Changing the signal type (lfo, music, voice) does not change the situation.
The strange thing is that this issue does not occur when the digital signal input, with the same Audio MIDI Setup settings, is recorded/monitored in other applications, like Quicktime or Garageband. It looks like Max can not properly handle the signal from the combined optical digital audio input.
I have also tried Max/MSP 4, but the same issues occurs.

Is anybody familiar with this issue and/or could anyone advise me on a way to make this setup work?

Thanks,
David Kiers

#43024
Mar 26, 2009 at 2:08pm

I also tried to send and receive audio between two macbooks running Max 5 using the digital in and outputs and got the same problems.
I can confirm other programs such as quicktime function properly using the digital in and outputs.
It looks like a bug in Max 5. Is there a quick fix possible?

Best Lev

dk!cycling wrote on Thu, 26 March 2009 04:42
Hi,

I am trying to get a digital stereo audio signal from one Mac mini into Max 5 running on a second Mac mini. The mini’s are running OSX 10.5.6.
I am using a TOSLINK cable with mini-TOSLINK jacks to connect the two Mac mini’s, plugging into the combined optical digital audio output on the output Mac and plugging into the combined optical digital audio input on the Mac that is running Max 5.
On both the Macs I have tried all the possible matching “Audio Input” and “Audio Output” settings (sample and bit rates) in the Audio MIDI Setup window for the “Digital in” and “Digital out” sources.
Max properly switches to Digital In and to the right Sampling Rate and starts playing the input signal correctly, but a persistent problem starts distorting the input signal after a variable amount of seconds (+/- 20 secs) after turning on the audio.
It sounds like a sync issue: a buildup of delicate ticks into a noise layer over the input signal. I attached a recording of the noise building up.
The issue temporarily disappears when the dsp is turned on and off, returning again after some tens of seconds. Changing the signal type (lfo, music, voice) does not change the situation.
The strange thing is that this issue does not occur when the digital signal input, with the same Audio MIDI Setup settings, is recorded/monitored in other applications, like Quicktime or Garageband. It looks like Max can not properly handle the signal from the combined optical digital audio input.
I have also tried Max/MSP 4, but the same issues occurs.

Is anybody familiar with this issue and/or could anyone advise me on a way to make this setup work?

Thanks,
David Kiers

#154181
Mar 27, 2009 at 10:41pm

I’ve been able to confirm the issue and have passed it on to our engineering team. I wasn’t able to find a quick fix in the meantime.

For what its worth, I did notice that often after a while the distortion seemed to go away on my machine, but it sometimes took a few cycles of sweet distortion build up.

-Ben

#154182
Mar 27, 2009 at 11:11pm

Thanks Ben, I’m looking forward to their conclusion and possible fix.
David

#154183

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