I have a Yamaha CLP-470. Love it. But I have noticed something. If I pick the Grand Piano 4 sound (normal, not the "variation"), while it normally sounds OK, if I hit (more perceptible at a loud volume and hitting the key somewhat hard) the RE that is one octave above the middle DO, then there is a cyclical grating background sound that can be heard for a few occurences (about 2 seconds).
The further away from that RE you strike a key, the less perceptible it is. It has almost completely disappeared when you reach the SOL above or below that RE.
The CLP-470 of my dealer has the same behavior. One of their CVPs (don't remember which model, but with a color display) has it on Bright Piano 2 (I suppose they used the same samples).
My spectrometer shows a peak at around 120 or 130 Hz when I hit that RE key (in addition to the main frequency of the note). This peak at 120 decreases the same way when you hit a key farther from the RE. So I think this could be what I'm hearing.
Can anybody who has a CLP-470 try it on their keyboard? Other CLP instruments?
It's easier to hear in a silent room or with headsets, but it's quite perceptible once you've noticed it...
Is their a proper means to bring this up to Yamaha?
Father and geek