Often I talk about piano and sound in good pianos or bad, but I often forget that most people don't have a wide frame of reference. Most pianos I visit belong to a family that has owned that instrument for decades. While I can't describe attributes of sound quality from when those pianos were new, I can describe that of a new piano. I tune between 800 and 1,000 pianos each year, and most of those are brand new from the factory. So what makes the best ones sound so great?
Describing sound is difficult, but can be achieved with practice. Try it. Describe the sound of the trains at Government Center in Boston. I can hear the shrill squeal of the steel as the wheels go around a bend. That sound is very sharp. It pierces and hurts your ears. Try to describe the sound of the ocean... It's sometimes calming, often bright, and carries on continuously. Now describe the sound that's made when you drop a large stone onto wet earth. It makes a dull thud as the ground absorbs the weight of the rock and the sound itself. These are pretty simple things commonly described in sound, so lets try something different. Describe your mothers voice.. It's not so easy, is it?
If that is too abstract for you, this is what musicians and piano technicians often deal with, describing the voice of something so abstract. We use keywords like "colorful," "bright," "warm," "dark," "dull," and so on. There are many factors that attribute to the sound of the piano, things we can easily change like the key height, the weight of the hammers and the distance they travel, the tuning. Then there are things that are not so easily changed; the shape of the cabinet, the length of the sounding part of the string, and even the strings themselves. We can control and reset many of the parts attributing to sound, but what makes a piano great is the voice that is coming from the parts we can not change and the energy in an instrument.
Piano construction has become a combination of science and experience, and I won't begin to state any opinions on shape and size and so on, so let's skip right to what I think makes the best piano sound. I'd like to use a real world example as my reference.
I tuned an asian made baby grand piano that measures 160cm. This is a fairly small piano, and short strings often result in poor sound quality. I like single notes that are very clear and ring like a bell. In the bass I listen for crisp power and sustain. In the tenor I listen to the clarity of the strings and their relationship with other notes in a chord. In the treble, the voice should be consistent with the rest of the keys, bright, and clear. Finally, when I play a chord, whether it's a simple power chord or a dominant seventh, when held out, they sustain for a long time. The sustain time on this piano was very long. Sustain over 30 seconds would be fair, but the sound in this piano rolled around forever, striking harmonics in the string scale and continued to beat between the cabinet, soundboard, harp, and whatever else it could find to energize it along. The energy inside an instrument is what makes a piano special. This is actually called stored mechanical energy or stored energy of position. Share or Like this if you found it helpful, and next time you are playing a piano, practice describing the voice. Maybe it's gentle and calm, like you're mom's when reading to you long ago. Happy Mothers Day!