Only issue with alt input is, only one input. Not stereo.
From the manual...
Auxiliary Input
The Auxiliary Input function allows you to feed a stereo signal, such as an mp3-player, into your PROFILER to play along with it. In the Output Section, the Auxiliary Input function is equipped with three mix controls: one to feed the aux signal to the MAIN OUTPUTS as well as S/PDIF OUTPUT, and two others to feed it to the MONITOR OUTPUT and HEADPHONE output. This allows you, for instance, to add an additional monitor signal to your HEADPHONE output, while the MAIN OUTPUTS stay unaffected. With the activation of “Monitor Stereo” MONITOR OUTPUT and DIRECT OUTPUT get paired as one logical stereo monitor output. The Aux In signal will also appear on both and its mix gets controlled via “Aux In >Monitor”. The auxiliary signal will not be affected by any internal effects.
You will need to purchase a special cable which provides the stereo signal via two separate TS jacks. Plug the left jack into the RETURN and the right jack into the ALTERNATIVE INPUT. Use the "Aux In >…" soft knobs to adjust the level.