Last night, a few of us DS106 Radio maniacs messed around live on the air. Jim ran the stream and several of us called in via Skype. We had a blast talking about all kinds of stuff, from The Twilight Zone, to collectible action figures, to I am Legend, to Charleton Heston. It was great, eclectic radio. Too much fun.

The one thing we all wished we could do that was not possible with the way the broadcast was set up, was to play audio clips through Skype so that they would play on air. When the “Talking Tina” episode of the Twilight Zone came up, for example, it would have been great if those of us calling in on Skype could have played a clip or two from the episode. (Jim could have played a clip, but that would mean he would have to switch audio sources from Skype, to iTunes and then back again to get us all on the air after the clip was done. That’s another problem altogether though — one that I hope to solve in the future if I can’t get Audiohijack works as it should.)

System audio does normally not register in Skype and there is no way to route specific applications, like iTunes, through it without expensive software. Wiretap Anywhere, for the Mac is one way to do this, but a single license is $129 and that just won’t do. So I started poking around, looking for solutions. The best I found so far is to route system audio through Skype with Soundflower and LineIn, both free apps. This is a bit messy (albeit fairly straightforward) and not an optimal solution as all audio goes in to Skype so that every email or IM alert or even volume adjustment is audible in the Skype call. You also hear your own voice through your audio output, which can be somewhat annoying. Regardless, it works. Callers can play audio clips that are broadcast over the stream and that can make for some fun radio.

I’m going to look for a better solution, but here, in the meantime, are step-by-step instructions for sending system audio to Skype in Mac OSX. These are based on pretty good instructions I found in the Skype forums, but I hope these are somewhat clearer. Rock on!

1. Download and install Soundflower and LineIn. Both are free.

2. After you install Line In and add it your Applications folder, find it in Finder, right click on it and select “Duplicate.” You’ll now have “LineIn” and “LineIn copy.”

(Feel free to rename the 2nd one to “LineIn 2? or something along those lines.)

3. Now we are ready to feed all audio output to Skype through Soundflower. LineIn will help us get the job done. Begin by firing up System Preferences, selecting Audio and set input to your headset and output to Soundflower (2ch). Like so:

And so:

4. Now fire up LineIn and LineIn2. In the first instance set “Input from” to the headset, and “Output to” to Soundflower (2ch). In the second one, set “Input from” to Soundflower (2ch), and “Output to” to the headset. System audio now plays through the headset, rather than speakers. (You can change this, if you wish, by setting “Output to” in the second instance to appropriate source.) Click “Pass Thru” on in both. Like so:

5. In Skype, select the Audio tab in Preferences and set output to Soundflower (2ch):

You are now in business. You may notice that audio played through, say iTunes, sounds a bit low, but my experience has been that it sounds just fine to the people on the other end. Enjoy. It will take a little while to get used to operating this way (you may need to shut off your mic at times, for example, when playing music or not speaking) but I think being able to do this is worth the quirks of this set-up. If I find something better, I will be sure to post it.