A question we hear all the time is, “Why doesn’t Kurzweil’s K2600 have as much polyphony as some of the other professional keyboard workstations in its class?”
There are several points to be made here. Some of the reasoning may only be known deep inside Kurzweil. What we can tell you is that the philosophy with which Kurzweil has historically approached developing instruments tends to put much more emphasis on sound quality rather than quantity, or on bells and whistles. Not to imply that polyphony is a frivolous addition to a synthesizer, but there are some machines out there with great polyphony that fall down in other areas. In fact, we’ve heard quite a few synthesizers exhibit timing anomalies once they are asked to play more than 50 or 60 notes of polyphony. Or, in some cases, other aspects of the sound become degraded. This is usually a function of having a processor that simply isn’t fast enough to process all that information in real-time. The Kurzweil can play all 48 notes and sound just as great as it does playing one note.
Kurzweil is also well respected for having the most sophisticated voice-stealing algorithm around. As is the case with a number of things under the hood of their current machines, this technology was originally developed years ago. In this case it can be traced all the way back to the legendary K250, which at the time was known to have the most believable piano sound of any electronic instrument. The K250 had 12 voices of polyphony! Necessity is the mother of invention, and at that time voices were very difficult and expensive to add to a keyboard – they required a lot of redundant circuitry. So the engineers at Kurzweil studied how people play and figured out a very involved instruction set that enables the keyboard to constantly monitor the notes being played, so in the event it needs to turn off a voice to play a new note (an occurrence that was common on the K250), it can take a note that will generally not be missed. This is one of the more overlooked and/or misunderstood parts of the Kurzweil system. It really is amazing how well it works. In a performance setting the keyboard behaves as if it has twice the polyphony it actually does. (For those who are interested you can get a bit of a visual look at this in action. On a K2600 go to the Master page, press the Utility soft key, and then press Stealer.)
The core sound engine used in the K2600 was developed quite a few years ago, and in some ways the OS still resembles the K2000, which came out in late 1991 (and had 24 voices). In many ways that instrument was years ahead of its time, as is illustrated by how successful the K2600 has been 10 years later.
It’s always tempting to focus on specs and features when making important equipment decisions, and they certainly can reveal important distinctions; however, one has to also step back and remember that we are making sounds here. It’s usually a good idea to make subjective assessments of sound quality as well. Finally, keep in mind how you will use an instrument. In many cases there is simply no need for 128 voices of polyphony so there’s no sense in putting too much emphasis on it. Rest assured you either pay for it or give something else up to get a capability like that.