Yeah...I've been doing that too. I actually have my tri-step counter stop if the wavelength is less than 8 (I don't remember why I chose that number... I think I saw it in some other player's source or something). Before I put that in I noticed the same problems you were. It's not like a clicking though... it's just a really really high-pitched note.

At this point I'm willing to bet that the note shouldn't be shut out because of it's frequency.. but rather the linear timer isn't exactly accurate and the sound should be cutting out before the wavelength gets reset to zero. This is probably just another tweak to compensate for the inaccurate linear counter.

I gotta figure out the proper way to do all this stuff.