"Recording" is the phrase that many people think of when then hear Audio Hijack Pro. This venerable Mac app has been helping users record system audio for years. But if recording is all you think of, you're missing a large part of what AHP can do for you.
Yesterday, I installed Spotify, the new ad-supported on-demand music player, in order to give the application a spin. Almost immediately I started up a hijack session as well. And it wasn't about recording.
With Audio Hijack Pro running, not only did I instantly have one-click muting -- a big help during the workday when phone calls come in regularly -- but I also was able to tweak my volume and adjust the playback bass and treble independently. AHP offers over a dozen real-time filter effects that allow you to fine-tune your audio in real time.
Eventually I found the Spotify setting that caused me to turn to Audio Hijack Pro in the first place -- in the Sound preferences, the app defaults had "Set the same volume level for all tracks" checked -- but even after I resolved that, I left AHP running in the background automatically adjusting Spotify's audio stream to my preferences.
You can also use Audio Hijack Pro with Airfoil to stream Spotify to your home stereo speakers. Rogue Amoeba has posted a how-to over at their site.
Audio Hijack Pro costs $32, and offers a free trial period.