SpeAna is the simplest and minimal spectrum analyzer Mac app that is the best
companion with Oscillo. You can discover synths in a traditional way with backup
of the latest technology. It spends significantly low cpu%, so you can keep
watching it without a worry.
Select your desired audio input device and channel, you'll watch frequency vs level graph.
Leftward- lower frequency, rightward- higher frequency, and upward- higher level.
You can typically use it to watch how a filter sweeps. Hit Pause button (or space bar)
to pause/resume SpeAna.
Mac OSX 10.6 Snow Leopard or later, both in 32-bit/64-bit modes.