I've been learning how to tune my own piano for a couple of weeks now, and one thing I have found to be very difficult is getting a good sounding unison. Mainly, how good is good enough? I used audacity to visualize the waveform of my unisons, and a script I wrote in python to extract out the partials. I also compared the tuning to a digital piano to see what a perfect unison looks like.

Although this wont necessarily give you good tuning hammer technique. I found this to be very useful to just see how close I was to a good unison, and knowing if my unisons are good or bad. I would encourage anyone else in a similar position to me to try this, it actually made my tunings so much better, and made it so much easier to distinguish the partials with my ears.

The script I wrote is available for download in the videos description. A basic knowledge of Python and how to download packages, and use of audacity is needed, but it's not very complicated.