Using an audio interface with multiple inputs

Question

Hi,
I'm currently facing an issue where I need to be able to use the audio from a microphone and a keyboard through Skype calling. I have them both plugged in to a Focusrite Saffire Pro 24 audio interface. The problem is that only the microphone plugged into input 1 seems to be coming through, as if Skype will only address one channel of the interface. Is there any way around this or a different method you have used in a similar situation?
Thanks,

Answer 1

I stumbled upon this thread in searching for some deeply hidden feature in Skype, but alas, there may not be a fix within Skype.  I realize the parent topic is very old, but I hope this can hope anyone in need of a solution (or get skype to incorporate some sort of summing feature).
That being said, there is an alternative for those of us with interfaces that have fully customizable routing.  Fully customizable routing, and more than your standard two (stereo) outputs, and at least one more input than you need in total for microphones.
What we're going to have to do for our podcast (one member is on vacation, states away), is hook all microphones into inputs that are not input 1. As far as I can tell, Skype will only recognize input 1.  In your interface's output routing software, you will need to create a submix/monitor mix (whatever they will call it) that sums (combines) all of the microphones together.  While you have the ability to add the software/daw return to this mix, you typically will not want to, as it could create feedback for the person joining the conversation via skype.
After you have created this submix/monitor mix (and be sure to double/triple check that input 1 is not involved with this mix at all) you will assign this to an auxiliary output... so say, your interface has 4 outputs, assign it to output 3.  Then lead a cable from the physical output 3 into the physical input 1 on your interface.
What this accomplishes is we're effectively sending all microphones into input 1, so your Skype recipient will be able to hear a mixdown of all microphones.  Certain interfaces will also allow you to do this routing without cabling.
There are more things to keep in mind, like if you're recording the call, you'll want to run a parallel output from your Main DAW/Software return into another physical input, but again, quadruple-check that you are not monitoring that track into your main buss as it would create a horrible feedback loop.  Generally I'd have the caller record their audio through Audacity or something free, but getting their recording on my end makes for syncing the call to the room recording so much easier... SO MUCH.
TL;DR
1) Make sure you have more than 2 outputs, and 1 more input than you would normally need for mic's.
2) Plug microphones into inputs 2 and on, saving input 1.
3) Use interface's software/routing mixer to sum all microphone inputs (EXCEPT 1) to an unused physical output.
4) Route or connect that output into Input 1.
0-5) For the love of all audio gods, make sure you are double checking to avoid feedback.
I also recognize that with the appearance of things like WavTap and Soundflower that there are other solutions -- but this is one option for those of us that do not wish to explore those options.