The Aux input and the digital input are both handled an off-the shelf DSP, and I don't have the DSP's spec sheet handy right now to look it up. Whether or not it can be mixed would be at the mercy of the DSP's capabilities. Anyone have that PDF file handy?

Anyway, even if you could mix it in the DSP, the player software would have to be altered to get the job done, and I'm not sure that's controlled by a hackable piece of code or not.

Another solution would be to use a passive line-level mixer and send both devices into that. I don't know if that's a common car audio component or not, but it's very common with musician's equipment.

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Tony Fabris