S/PDIF mono vs. stereo issues

[mickeyrouse]

Not sure if this is a Pro Tools issue or Universal Audio/Apollo issue, but here goes.

I have recently installed an API A2D 2 ch. pre/converter, intending to use the S/PDIF input of the Apollo to increase the number of input channels by 2. Eveything seems to work through appolo, console, and into the mix/monitor view of PT11. Except if I have two S/PDIF channel inputs enabled, both get the same signal. They are mono tracks. Should they be stereo to get both channels differentiated?

[Darryl Ramm]

Well actually, it is almost certainly an issue with how you are setting things up wrong (in Pro Tools), Pro Tools and your interface and outboards preamp/converter are likely working exactly as expected.....

You are likely recording two separate mono sources on your S/PDIF connected preamp. Right? (or if say you are using a stereo mic speak up now...) If so you want them going to two separate mono tracks in Pro Tools. And each mono track in Pro Tools comes from a mono source, one of the two possible inputs on the S/PDIF input. Whether those two totally separate inputs can also by convention be used for L/R Stereo is irrelevant to what you are doing. You need to select the correct one of those two mono inputs (by convention labeled as sides of the Stereo inputs) in Pro Tools.

If that Setup>IO page or the input selector in Pro Tools makes no sense to you then start with the Pro Tools Reference Guide.

If you are still stuck then post screen shots of your Setup>IO>Input page in Pro Tools and what options are showing up in the IO Input sector for those tracks, have selected as the input of each track. Make sure you are trying to record each input to a *mono* *audio* track in Pro Tools.

Most common confusion like this starts with folks creating stereo tracks for mono sources. Easily solved with a large wooden stick. I know you said mono tracks, but doublecheck. If its something else screenshots will help.