If the weather is stable, my violin drifts less than 1/4 of a Hz over the course of a week, let alone a single playing session.

Wow, impressive stability. In case of violin (bowed instrument), the waveform stability is visualised very well. Closer to sine wave. I tend to see less harmonics than plucked lutes like South Indian Veena. Please select 2 or 4 waveform periods in settings, set the desired reference note and try.

Thanks. I've been looking for a new app to give me immediate feedback on my pitch accuracy while I play, because the violin has no frets and my ear isn't good enough yet to identify whether I'm a little sharp or flat on each note. I think realtime feedback could really help me train my fingers.

I'll post more detailed feedback in a day or two when I've had time to experiment. Hopefully you'll still be checking the thread.

Post your detailed feedback when you have time or e-mail us. Will be checking the thread. If there is even a slight variation of pitch w.r.t reference note the visual feedback will rotate. But, the feedback would give an idea about the deviation.

There are also tuning apps that draw the cent deviation as a line, I think the T1 tuner is one such app, you can see a line graph moving and vibrating as you play your note. A similar app to veena is the airyware tuner that shows the soundwave graph moving left or right.

> me immediate feedback on my pitch accuracy while I play

The visual feedback needs manual reference note settings. That is the only limitation.