Soundquest -
Do you mean the melody sound? I put a ton of time into developing that patch, and there is such an assortment subtleties to it that it can have a variety of characteristics, including flute, clarinet, and a touch of oboe. As for the PEK patch, no high pass filter was used. Based on the position of the cut off frequency controlled by the modulation wheel, you can get that throaty metallic quality when you want it that is the magical quality of the Evolver. Still, I just love that Poly Evolver Keyboard. I've not grown tired of it in the least.