I have a Casio Privia (px120) keyboard -- so far it has been working great. I've recently hooked up a midi-usb adapter, and have been using it with some old windows software (Piano Discovery system). Now, after it's been running for a while, I get a real weird sound when I play. The notes don't have a full piano sound, instead they sound like the wave form is missing some elements, almost like a very poorly generated piano sound. And I get different levels of distortion like this depending on how hard I strike a key. It almost sounds like I'm getting an under-voltage condition on to the sound-generator chip on the keyboard. Is that even possible with any midi setup?

As soon as I unplug the midi cable from the back of the keyboard, it returns to normal. Plug it back in, and I get that distortion again. Also, the music that is generated by the software comes out cleanly -- I only get the distorted sound when playing. Now when I've shut down everything and let it set for a while, it all came back to normal.

My setup includes the laptop connected to the no-name-brand usb-midi cable, plugged into the keyboard, and using the internal keyboard speakers & amp. For the record, I've also seen this periodically with a different keyboard (Miracle piano keyboard), hooked up to a sound-blaster midi port connected to a Linux box.

You are going to have to reduce the number of parts inthe system to the minimum needed to reproduce the problem.

For example do the poor sound occer with only the MIDI interface connected to the keyboard and not to the computer. How about it connected to the computer but no software running. At wat point dooe the problem occur?

What about if yu use different MIDI software or a different MIDI interface cable?