DJM S9 Switching input channel when not using serato??

Im on a Mac. I know i can route the headphone output to the line in on the mixer, but i want it to where i can just keep the usb plugged in and be able to switch the channels the computer audio outputs at. 

Thank You

I guess pioneer thought everyone scratched on the right deck??... I have my headphone output on my mac routed to the aux in on the mixer as a work around (alternatively can also use the line in on ch. 2). But I don't understand why i have 2 perfectly GOOOOOODDD sounding audio interfaces on my mixer i can't scratch to =\ ...

Are you using a Mac or PC?

yeah this is exactly what I'm trying to solve as well. The same issue - I can't scratch to looper on a left deck, because the output from computer plays in ch 1 3... I am on OS X 10.10.5 

Copied from the other thread:

Having exactly the same issue. Prefer to scratch on the left side, and it's not posssible to get the standard audio output to the right side. I'm on windows btw.

My workarround is to use the onboard soundcard, hook that up to the right line-in and setting the windows sounds to the onboard soundcard. This way I'm able to scratch to a looper.

Btw it's a shame that something like this has been overseen in developement, especially on a scratch mixer.

Yup, it's like having 2 perfectly GOOOOOODDD sounding audio interfaces on my mixer and none of them supports 64bit *cough cough*.

I think only solution for now is to buy a "jack to RCA" cable and route macbook's headphone output to aux in on the mixer. This allows me to train scratches on both hands without need of switching channels or anything else. Works both analog / digital (with opened Serato DJ)...