Mac Pro optical out & brief hiss at regular intervals

[daBassAndDaSax2]

Hi, all.

I'm virtually brand spanking new to this, so I'm unsure whether this is specific to Macs, or even if this is expected behavior.

I was trying to use my MOTU 828MKII for phone calls in Gmail. I couldn't get the output to work via Firewire, so I plugged in the Mac's optical out to MOTU optical in (for the first time). It worked! (Might even try to get it to work with stupid Skype!) But, there is a hiss about every second or so. Because of the frequency and consistency, seems like that is a synchronization feature of some kind, but I'm too green with recording to have dealt with this before.

Any ideas of how to get rid of the hiss, or better configure my Mac + MOTU for regular interactions with computer apps?

Thanks in advance,
Ali

[daBassAndDaSax]

FYI, posted this with a temporary account. Back at my old one.

-Ali

[mikehalloran]

For your 828 to work as designed, all audio goes out to it. Right now, you are using it as an optical interface - to drive speakers? headphones? the same way I use a Logitech interface to my speakers. The interface is supposed to take optical signals in and out through the FW bus.

Apple and MOTU optical ports use the S/PDIF) protocol, 16 or 24bit

Crack the manual and set it up properly. It should work

[daBassAndDaSax]

Thank you, Mike!

I see what you're saying. That makes sense. I guess I have two questions, then:

1) If there is audio from my Mac's bus that I want in my 828, but it is not coming in via Firewire for some reason, is it standard practice to use another Mac out like the optical port to get that audio to my 828?

2) More fundamentally, I guess: is it possible for any sound that is present on my Mac's bus to be sent through Firewire? In my experience, the answer is "no". I have been unable to get sounds from my browser and from Skype to show up in my 828. I guess I could see if I could assign the audio to a track in Logic, and access it that way over my monitors? I was hoping to get the data to come through live rather than using an intermediate step, like recording a Skype or Web audio to a WAV, and then accessing it with a sequencer.

Reading the manual tonight!

[mikehalloran]

The classic setup is that all audio goes in/out/through the 828. You start by setting up CoreAudio - (Sound in your System Preferences). Select your 828 for Sound Effects, Input and Output.

Once set up properly, all audio now is present at the headphone outs - you can also route it to the other outs to drive speakers etc.

Once done, you now set it up in DP.