Radio streams are just the start: there are countless reasons why you might want to sample audio from an application that lacks recording capability, from Game Boy emulators to experimental soundware. Last month, CDM shared a few tools and asked you for tips for app-to-app recording. Here are the results (which I’ve tested further):

Mac OS X – Winner: Audio Hijack. The most flexible app for recording audio from any application(s), hands-down, is Rogue Amoeba‘s Audio Hijack. It’s easy to use, ultra-reliable, and constantly updated; the version 2.5 update has just arrived with Tiger support, AppleScripting, advanced mixing, and lots more. Well worth the US$16-32 price.

Windows – Winner: Audacity. Windows users have a number of options, including the fairly advanced Virtual Audio Cable for inter-app routing and US$11.95+ Total Recorder. Check the comments in the original story, though, and you’ll find results from some applications are mixed: definitely download demos before buying.

Why bother with those, though, when the most reliable solution is free? The fabulous, free, open-source audio editor Audacity can record the sound card mix: click the drop-down menu next to the microphone input level to select input source, and you’ll see “Stereo Mix.” Select it, hit record, and audio from your apps is automatically recorded. (You may need to experiment with gain — I found the input tended to be on the hot side — watch the waveform for distortion and turn down the input level.)

I’ve had excellent luck with Audacity on my system, though when I tried it on other PCs I occasionally ran into a hitch: again, try it first, though I’d certainly start with Audacity as it’s free. Incidentally, the reason I initially missed this technique is that it doesn’t work on Mac; the Mac Audacity appears to lack this feature.

So there you have it. Fire up your Game Boy emulator or the game music player Audio Overload for some instant chip tunes, or record text-to-speech software for some Radiohead-y goodness!