Cool, this helps! If I set it to e.g. 3MHz it seems to change pretty smoothly over the whole range. I have to test this a little more but I don't know when I'll find time for it. If I find a value that suits me, how can I set this permanently? Thanks so much for your help! Tobias > isaset 0x295 0x296 0x14 0x00 0x70 # 24 MHz > isaset 0x295 0x296 0x14 0x10 0x70 # 24 MHz > isaset 0x295 0x296 0x14 0x20 0x70 # 12 MHz > isaset 0x295 0x296 0x14 0x30 0x70 # 8 MHz > isaset 0x295 0x296 0x14 0x40 0x70 # 6 MHz > isaset 0x295 0x296 0x14 0x50 0x70 # 3 MHz > isaset 0x295 0x296 0x14 0x60 0x70 # 1.5 MHz > isaset 0x295 0x296 0x14 0x70 0x70 # 0.75 MHz > > As a rule of thumb, lower frequencies should give your better control, > but you might also bring annoying sounds. Please experiment with > different values and report.