Note clipping in a synthesizer

Hi.

I have a simple synthesizer question:

I’ve created a simple synthesizer and noticed that when I play one note at a time it sounds good
but when I play notes together or with a short distance there’s some ‘clipping’ noise.

What am I doing wrong? (the eternal question again…)

Thanks.

Too loud, perhaps…?

or this? http://www.rawmaterialsoftware.com/viewtopic.php?f=8&t=3827

It’s now much better, Thanks!

BTW, anybody knows a good synth book I should read?

“Becoming a Synthesizer Wizard” looks nice, but I’ll be happy to hear about more books on this subject.