My grandmother is an incredible pianist. She is also losing her hearing and for the last five or so years, it has been bad enough that she can't play piano.
I have talked to her about the idea of getting her an electronic piano so that she could just turn the volume up and play through headphones, but she says the problem is deeper than just volume.
With her hearing loss, and I'm sure that of many other people, frequencies near the limits of hearing range sound out of tune. I imagine this has to do with the hairs on the cochlea tuned to those frequencies failing, and others nearby trying to compensate.
My idea is an electronic piano specifically tuned to compensate. When buying such a piano, the buyer would be tested by an audiologist to determine exactly what frequencies were distorting and by how much. The piano would then be tuned to compensate.
Since these people would probably still like to play for other people, and since the piano would sound out of tune to everyone else, it would have multiple, configurable outputs. If you wanted to play for others, you could have the headphone output play the compensated sound, while the speakers or speaker output would play the uncompensated sound.-- Joolin, Jul 29 2010 Shepard tone http://en.wikipedia.org/wiki/Shepard_tonefamous example [csea, Jul 30 2010] Sounds reasonable; I wonder how easy it would be to do? I didn't realize that perceived pitch might change, but I suppose it makes sense.
However, I wonder if there's another way to achieve the same end, perhaps better.
There is a famous example of an electronically-synthesized musical scale which rises tone by tone indefinitely, and yet never seems to get higher.
The way it is done is by varying the harmonics of the notes. As the notes get higher, a sub-fundamental (an octave below) is gradually introduced whilst the highest harmonics are reduced. So, by the time you've gone up an octave, you've actually returned to your original note without realizing it. It would be interesting to know if the illusion (of a continuously rising scale) is perceived by your grandmother.
Now, suppose we take an electronic piano and alter the harmonics. Suppose also that your grandmother's hearing is only good in the middle of the keyboard. We arrange it so that the higher notes have sub-fundamentals (ie, an overtone an octave or two octaves below the fundamental), whilst the lower notes are enriched for higher harmonics.
In this way, all notes will have strong harmonics which are within the hearing range. Bass notes will sound a bit "tinnier" than they normally would, and high notes will sound a bit "bassier", but I think you'd adapt to this quite quickly.
(You could do a similar thing with electronic drum-kits, and call it the Beathoven.)-- MaxwellBuchanan, Jul 29 2010 Brilliant! Encore! Bun! [+]-- Grogster, Jul 30 2010 Possibly complicated, depending on the nature of the hearing loss. But well thought out and described. +-- csea, Jul 30 2010 random, halfbakery