a440.wav +00c (the second zero was flickering slightly, but it stayed on 0)
c523.wav +00c (second zero bumped up to 1 a couple times during the playback, very briefly)

Looks like a nice and simple little app.  I hope it works out.  The waveforms on the top screen look really nice.  I tried it with my guitar and the meter was all over the place, so it looks like that´s not quite ready yet.  Although it stayed a bit more steady with my voice than with the guitar.  I assume that´s the timer issue you´re talking about.  Anyway, I hope you can do something with it!  I would definitely use this app.