I've been trying to spend some time with the violin on a semi-regular basis. When it's more regular, it sounds less bad. I have a vague idea when i'm playing whether i'm horrible or tolerable, but listening to one's own self is a whole other thing.
Today it was raining, so i had to play indoors. I hooked up rosegarden and set a cheap but remarkably effective gooseneck headset mic in the middle of the room and started playing. You don't really want to hear it, trust me. I'm trying to play more longingly minor keys because i like the sounds of them. They sound like i feel a lot of the time. Still, my fingers don't really know where they are. While i'm playing, the "music in my head" cancels out many of these mistakes before they reach my ear. In the recording i can "see" where i'm trying to go, but i hear all the mistakes quite clearly, too!
I was checking on the web to see if Rosegarden has a spectogram viewer inside it when i found this wonderful tool for audio visualizion - sonic visualizer. I haven't been this impressed with audio software since, oh, rosegarden? It's currently devouring 100% of one of the cores of my CPU rendering the full 10 minute spectrograph as i write this, but it updates to the current view very quickly. It's user controls are *smooooooth*.
Here's a spectrograph view of 15-odd seconds (don't know why the time axis isn't labeled here...), with frequency and amplitude scales shown on the left. I never really thought about it, but the harmonics are more widely spaced for high notes, accounting for the perceived "pureness" of the tone? You can see the vibrato, too. Pretty cool. Click on the image to see it in decent-resolution.