1. It enables sending AC3-encoded audio e.g. 5.1-channel on DVD directly to SPDIF output. Manual has some details too. Leave off if not doing this. (Switching on doesn't seem to have any negative effects here w/ Pro 24, but this is pointless.)
2. This might work, and it's not a bad idea at this point. Some devices can deal with either type of source and the status bit & voltage differences. Or a dedicated converter can be used. Q. Can I connect an AES output to an S/PDIF input?
You could instead try a SPDIF coaxial to optical converter, like this: http://www.amazon.com/Digital-Coaxial-Toslink-Optical-Converter/dp/B001622FL8/ (Monoprice.com has it for $12 but the site seems to be down now.)
3. Usually it means your preset level is too high. Check the Output 1 Boost/Pad parameter in the I/O: Audio menu first, and set to 0 dB if not already. Also verify Out 1 Global EQ is set flat at 0 dB (or close enough) with MAIN slider at 0 dB. Then reduce the amp block OUTPUT LEVEL parameter until the clipping stops. Level could also be adjusted in a later block (cab etc.) or OUTPUT block.
Before you do this, it might be useful to gather some details: Has the clip indication been happening on every preset? What's the CPU usage (UTILITY: STATUS page) on the presets that light the clip LED? Does this happen with no USB cable connected?
Once you've reduced level to avoid clipping: If you set the Saffire to internal sync, does monitoring the Axe SPDIF output happen to sound okay? It's not the correct/ideal setting for one-way SPDIF, just a troubleshooting step. The sound may seem fine, or have a slight crackle/distortion, but I'm wondering if the major dropouts you described still occur.
Post a video if you can. I don't know if there would be any important settings in the OS X sound devices menu, but could you get video or a screenshot of that too?
It seems like the clipping is occurring with default presets only. When I use a preset I created, the volume (not tone) is much lower and the clip light is not on.
I do also notice an added distortion/clip sound on the presets that clip. When I lower the output and avoid the output clip light, all sounds well. Then I just bump the volume up on the interface to the monitors to compensate the volume in the room.
Everything as of two hours ago when I shut down was working 100% perfect. Will see what tomorrow brings.
Thank you for your help!
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