I can't believe there's no reviews on this synth! I think I am GTG13's number one fan. Let me share with you why I like it so much...
* Excellent pulse-width modulation sounds. On GTG13, you can assign an LFO to each oscillator's pulse-width and modulate them at different rates for very thick virtual analog sounds.
* 2 LFOS for the filter. LFOs 1 & 3 can both be assigned to the filter cutoff frequency. This is great for creating complex modulating pads.
* Velocity sensitive. GTG's got a knob for adjusting how much key velocity affects the filter.
* Onboard chorus. It's nice and warm... don't think I ever turn it off.
* Oscillator sync. You can sweep the oscillator pitch with an LFO or the filter envelope for some hard-edged tones.
* Filter types. GTG13 has the usual lowpass, highpass, and bandpass, but it has a cool band-reject filter too.
It's not perfect. I'd like to have optional tempo-sync on the LFOs, visual readout of values, a ping-pong delay, some finer LFO values for pitch vibrato. Blah, blah, blah... All that doesn't matter because it's free, it sounds fantastic, and it's quite flexible.
No docs that I could find so I had to rate it a 1 but Mik's synths are pretty easy to program so that shouldn't cause much difficulty.