Based on my recent frequency measurements of my Polysix, where I saw a 4-5 dB hump at 12 kHz, I decided to attack the raspy issue and do some modifications. While I didn't just go and cut the 1K resistor as I previously suggested (thanks to Tony for the caution), I did explore other solutions to flattening that hump. I ended up putting a 33K resistor across R168. My new frequency response measurements show that the high-frequency treble boost is flattened, but not eliminated. I think that I struck a decent balance. If you're interested in an audio comparison, check out:
http://synthhacker.blogspot.com/2013/08/polysix-flatten-treble-response.html I'd appreciate your thoughts on the change in sound... Chip --- In
polysix@yahoogroups.com, <chipaudette@...> wrote: Also, if you like the way that the mod sharpens the attack, but you don't like how buzzy it now sounds, you can eliminate Korg's own modification to boost the highest treble frequencies...
http://synthhacker.blogspot.com/2013/07/polysix-removing-korgs-treble-boost.html Cut that 1K resistor (the upper one, not the lower one!) and you'll flatten the high frequency response!
Chip