Native Instruments' Pro 53 is a software version of the original polyphonic Sequential Prophet 5. When placed into Unison Mode, all five of the Prophet's voices were used to produce a monstrously huge monophonic sound, perfect for screaming synth leads. The Pro-53's total polyphony is actually limited only by the CPU power of the computer it is installed on. This means you can have as many voices as your hardware allows. You can control the number of voices assigned to Pro-53 via a front-panel control. Since you could easily have a robust enough computer today to deliver 16, 24, 48, or even more voices, switching to Unison Mode can result in overkill, since each voice actually triggers two oscillators. (Pro-53 also subtly detunes each voice to make the sound even fatter) With this in mind, you may wish to use the Pro-53's "virtual control panel" to limit the number of voices on a unison patch, thus allowing more useable voices on other patches if you are using the Pro-53 in multitimbral mode. To adjust the number of voices available on a per-patch basis, click and hold on the Voices display, then drag the mouse up or down to change the value. This is particularly useful if you are not the happy owner of one of the latest quad-core computers. Older Macs and PCs are perfectly capable of producing excellent sounds, but you wouldn't want to push the CPU load on these older computers. By limiting the voices, you can keep from running out of voices in a complex piece of music, regardless of the age of your computer.