I've been happily using Verituner piano tuning software for years. It's expensive, but it gives me tunings as good as, if not better than, what I've experienced paying for a professional tuning. Now a number of German physicists have made a stab at solving the age-old piano tuner's dilemma: getting the various intervals of your average piano to match up in a pleasing way. This is always a compromise because of the inharmonicity of piano strings. The program is called "Entropy Piano Tuner" and it measures ALL the partials, both frequency and relative amplitude, of all 88 notes of the piano; then it calculates a tuning for each note on the basis of that calculation. I followed the program's instructions quite carefully on 2 points: 1. I used a good external mic and placed it in a fixed position just outside the piano, pointing towards the sound board. 2. I double-checked my IH measurements, which are easy to do, but which can sometimes go wrong and destroy the calculated curve. The end result of my tuning--after attending to the above 2 issues--was an extraordinarily good tuning. Of course, you have to be good with a tuning hammer, and with setting the pin. Also, to get a dead-on accurate tuning, you need to know how to read the stroboscope, which in this case provides a picture of the fundamental, plus the attendant partials. You need to know which partials are important to pay attention to. Above a4 it's easy, because you're only concerned with the first partial. But things can get al little confusing in the bass and tenor! Still, fabulous tuner .... beautiful results. Not as flexible as the expensive Verituner program, but I must confess just as good, and free.