Since my new piano has now settled into its new home, the bass was a bit wonky.  Knowing that I am going to get it tuned professionally, I thought it would be a perfect time to experiment with my tuning hammer.  Pianos cannot be tuned properly with just a normal chromatic tuner.  Due to the inharmonicity of the metal strings, adjustments must be made on the bass and treble ends of the piano.  Typically the bass is tuned progressively flatter and the treble is tuned progressively sharper.  This creates the normal “piano” sound we are used to.  Professional tuners do this by ear, counting beat frequencies against certain intervals.

I am not a professional, but the Internet is a wonderful place and there are lots of piano tuning aids.  The one that seemed most interesting to me was The Entropy Piano Tuner.  This is an open source project by several very learned German piano technicians.  Having a laptop, and a very flat measurement microphone, I was in business.

The software is interesting because it uses a mathematical formula to compute the best deviation from standard tuning for each string.  Instead of using a smooth curve, each string is individually considered.  The workflow is simple.  First, I recorded each string into the software.

Recording Each Note

This process takes about 20 minutes.  The blue marks indicate where the current tuning falls.  The rough shape of the stretch tuning is clearly visible.  After recording, the next step is to let the software run its algorithm to calculate the ideal tuning for each string, taking the inharmonicity into account.  Basically, the metal strings do not vibrate purely as strings, like on a violin. Their mass and stiffness also cause them to behave a bit like rods.  This alters the normally pure harmonics produced by a vibrating string.  The software’s job is to figure out the best tuning for the string that puts its harmonics in the best relationship.


Analysis Complete

Now it is easy to see where the present tuning deviates from the ideal calculated by the software.

The final step is to tune the piano to the green lines. There is a special tune mode that makes this fairly straight-forward.  So, tuning hammer and mute strip in hand, I started at A0 and worked my way up.  The software is very accurate, and it turns out that tuning a piano is a very subtle affair.  Very small movements of the tuning hammer make a significant difference where a few cents are concerned.  In the past, I haven’t done much outside of touching up unisons.  The single strings went without much difficulty, but the double and triple strings gave me more hassle, as I learned the best way to tune unisons the hard way.

Almost Done

The piano is now in tune, and I like the results.  The low bass strings are now very resonant and sound much better, particularly the ones that I nailed within one cent of the calculated value.  The very highest octave of the treble was a bit bright, so I let the very highest notes down a few cents.   Their theory seems to work as advertised, and, as they suggest, a bit of fine-tuning by ear can be important.  It was a very time consuming process, due to my inexperience with the physical mechanics of operating the hammer.  I improved a LOT over the course of the exercise.  All total, I probably spent 10 hours getting it right.  That said, it was a great experience, and one that I probably won’t repeat.

The software is excellent, and works as advertised.  It does nothing to endow one with skill using the tuning hammer, however!  I am not fast enough to make it worthwhile financially, and it is as interesting as playing to me.  It was a solid learning experience, and it was interesting to play with the beat frequencies.  They are quite easy to count.  It also made me able to hear the stretch and its musical effect.  I am glad there are professionals who do this every day, and outside of perhaps re-running this software to inspect a tuning job, I will return to playing the instrument vs. inspecting it.