Birck Cox
Level 1 (147 points)
Desktops

Q: No sound from optical input on Mac Pro

I'm trying to work out some problems with my optical sound system, and I have a Sony DAT recorder outputting to my Mac Pro, Late 2010 5,1 running Sierra. I can bring up the signal from the DAT, via optical cable, into the Mac-I get a visual signal on the sound prefs-but no actual sound out of the computer, no matter which output I try: Internal spkrs, Line out, Digital out, monitor soundbar, or Bluetooth headset. Wassup? I've trashed the sound prefs and zapped the PRAM. No change.

Mac Pro, OS X El Capitan (10.11.3)

Posted on Sep 27, 2016 5:28 AM

by Mudge,Solvedanswer
Mudge Mudge
Level 2 (374 points)
A:

Unless you are running software that routes an input signal through to the output then it's normal not to hear anything.

 

As you're seeing something on the input screen of System Preferences it means that should be working fine. If you want a simple way to monitor the input through your output device:

 

1) Open Quick Time Player.

2) File -> New Audio Recording.

3) Click the small arrow next to the record button and make sure your optical input is selected.

4) Move the volume slider at the bottom of the window to the right to hear the input sound.

 

I guess the reason this isn't done by default is that it causes feedback on laptops where the microphone is right next to the speakers.

Posted on Oct 1, 2016 4:46 AM

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Birck Cox

Q: No sound from optical input on Mac Pro

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  • by Johnb-one,

    Johnb-one Johnb-one Sep 29, 2016 6:35 PM in response to Birck Cox
    Level 4 (1,891 points)
    Desktops
    Sep 29, 2016 6:35 PM in response to Birck Cox

    Hmm..that's sure odd. If you hold down the option key and click on the speaker icon at the top of the screen, you should see a list of all the available audio inputs and outputs, which you can also find under system preferences>sound

    other than that, try firing up Audio MIDI and see what it's set to, sometimes, strangely enough, it gets set to something odd like 96 khz or Line out, or some such.  other than that, depending on the appication you're using, you may have to change the recording souce and make sure that play through is engaged. your device should hopefully show up. I think it should be set as either 44khz or 48 khz

     

    sorry I can't be of more help

     

    John B

  • by Birck Cox,

    Birck Cox Birck Cox Sep 30, 2016 4:55 AM in response to Johnb-one
    Level 1 (147 points)
    Desktops
    Sep 30, 2016 4:55 AM in response to Johnb-one

    Thanks for the details, but I may have jumped the gun in thinking the computer was the problem area. It will take me a couple of days to go over the system to determine where the problem actually is-it may be the originating source rather than the computer, or something in between. I have both a receiver and a DAT tape deck that output a Toslink signal, and I may have trouble with both of them. Maybe I'll switch to HDMI. But thank you for the troubleshooting tips.

  • by Mudge,Solvedanswer

    Mudge Mudge Oct 1, 2016 4:46 AM in response to Birck Cox
    Level 2 (374 points)
    Oct 1, 2016 4:46 AM in response to Birck Cox

    Unless you are running software that routes an input signal through to the output then it's normal not to hear anything.

     

    As you're seeing something on the input screen of System Preferences it means that should be working fine. If you want a simple way to monitor the input through your output device:

     

    1) Open Quick Time Player.

    2) File -> New Audio Recording.

    3) Click the small arrow next to the record button and make sure your optical input is selected.

    4) Move the volume slider at the bottom of the window to the right to hear the input sound.

     

    I guess the reason this isn't done by default is that it causes feedback on laptops where the microphone is right next to the speakers.

  • by Birck Cox,Helpful

    Birck Cox Birck Cox Oct 1, 2016 4:52 AM in response to Mudge
    Level 1 (147 points)
    Desktops
    Oct 1, 2016 4:52 AM in response to Mudge

    Yo Mudge, you were right. I opened a recording program (Sound Studio) and recorded a section. Now I have another problem: Can you tell me how to match the KHz output from the source (a Yamaha receiver) to the Mac Pro? I don't know what the Yamaha is putting out, but what comes through at the computer sounds about 3X slowed down, like a Russian Basso profundo making a ransom demand. Thanks for setting me straight on what to expect.