New recording. This time it's obvious: http://www.4shared.com/mp3/2kERkweAba/glitch_3.html

Hope it's more clear now.

Hi p4thos

From the sound of the clip, I suspect the unit simply needs repair. You should first simply try reinstalling the latest OS just to rule out simpler stuff. Link below (step by step installation instructions included within):

http://kurzweil.com/product/pc3k7/downloads/

If the problem persists afterward, just playing the stock unit, listening with known-working headphones connected to the PC3K's headphone jack, then you will know with certainty this is a deeper hardware issue and one that requires proper service to suss and repair.

I sent the keyboard to the warranty.

I hope they identify the problem. To make sure, I sent the audio recordings and description.

I thank you all for the help.