Hi @ruudiboy,
Some great advice from @rockinghorsekid there!
This sounds a bit unusual especially if you have reset your keyboard. I’ll add a few notes and things to try.
With most of the instruments, when you press the keys very, very slowly you’ll hear a slight whooshing sound. This is far less pronounced in later instruments such as your KN6500. It was quite annoying in some of the early models if you were playing loudly through an amplifier. I’ve always assumed that it was some type of background processing that needs to happen when you press a key (far beyond my understanding all that type of thing). The whoosh is stronger when you have any digital effects running so I think it is something akin to having an effects pedal on a guitar, where the effect is live even if you aren’t playing, and can sometimes be heard through the amp (not that I play guitar). I assumed that perhaps the keyboard was triggering the effect anytime a key is pressed but cutting it off after a short time. Anyway, that’s all a bit of guesswork and not very relevant.
Is this issue the same through headphones?
If you can take a line out into an external amplifier (or say your home theatre system / TV Bar or anything that acts as an amplifier), is it the same?
Here’s what I’m hoping for you – it could be your modulation wheel or the ball controller ‘almost making a connection’. Your modulation wheel should normally be right down the bottom on ‘zero’. I can’t remember what the circular ball-type controller is called but its position will affect the sound so centre or ‘zero’ that. I’m not able to get my KN6500 out to do tests at the moment.
You can also try changing the overall instrument level of touch sensitivity to be aggressive or sensitive and see if that helps.
If this is only happening when you have a digital effect enabled I believe that chips or boards can be replaced but it isn’t easy to find someone with the knowledge to do it these days. I mention that because a few members have had that done over the years to fix similar issues.
Finally, if your KN6500 is actually a KN6000 with an expansion board to upgrade it to KN6500 you could check whether the board is loose. Instructions for fitting expansion boards are in the Downloads section of the website.
Fingers crossed,
Mike
If architecture is frozen music then music must be liquid architecture. Quincy Jones