Audio Hijack grabs the audio output of any Mac OS X Cocoa or Carbon application for your listening pleasure.
Rogue Amoeba's Audio Hijack (http://www.rogueamoeba.com/audiohijack/), as its name suggests, hijacks the audio of any Mac OS X application for doctoring and recording. Billed as an audio enhancer with DSP effects and an equalizer to beat all others, it's the audio recording that's of most interest to me. Figure 3-29 shows the Audio Hijack interface.
Launch Audio Hijack, select a target application, and launch it with the Launch button. Audio Hijack will attach itself ? this is why you must launch the target app from the inside ? and pass through all sound generated by the app. You can begin and end recording at any time using the Start Recording/Stop Recording button. You can forego setting a maximum duration if you're not sure what it should be, but I found setting it and letting it record unattended far more relaxing than remembering to check back every so often for fear of the audio filling up my hard drive.
Click the DSPs button and you can apply all manner of sound effects to the sound output and recording. Add flange or reverb, alter the bass and treble levels, display a pair of VU meters, or treat yourself to a 10-band equalizer with savable presets, as shown in Figure 3-29.
A friend pointed out that Audio Hijack is the perfect utility for recording live audio streams delivered via Real Audio. The application's timers act as an audio VCR of sorts, launching Real Audio and recording for a specified amount of time. Drop the recording of NPR's All Things Considered onto iTunes and sync with your iPod, and you have your favorite public radio on demand and portable.
Finally, I can grab the audio tracks from my yoga class video, allowing me to take my practice anywhere my iPod goes.
Audio Hijack is available for a 15-day free trial, after which it's only $16 for a fully licensed version.