Runs under: Windows 9X/ME/2000/XP with DirectX v8 or later
Specter grabs audio from whatever your sound cards is set up to 'record' and then displays the spectral content in real-time in a nice two dimensional 'graph'. The highest frequencies at top, the lowest at bottom. Left channel in the left hand side, right channel in the right hand side.
Grab it - it's free! (size: 174KB).