KURZWEIL MUSIC SYSTEMS
Questions and Answers About the
Kurzweil 150 Fourier Synthesizer
What is the Kurzweil 150 Fourier Synthesizer?
The Kurzweil 150 Fourier Synthesizer is a multi-timbral sound source, designed to work with any MIDI controller, be it
keyboard, guitar interface or personal computer.
Is it a sampler?
No. The Kurzweil 150FS produces its sounds using additive synthesis technology and a highly advanced form of Contoured
Sound ModelingTM, Kurzweil’s proprietary technique for analyzing and encoding the characteristics of natural sound. The
process of converting a sampled sound into a 150FS sound model is so complicated that even we are amazed that we can do
it.
It’s called a Fourier Synthesizer. Does this mean it only does harmonic sounds?
Actually it should have been called a "partial synthesizer" but then customers might think they weren’t getting a complete
machine. Each "partial" (sine-wave component) of a sound may have any arbitrary frequency which can either be fixed or a
function of the fundamental pitch. "Noise" partials are also available, which is one reason the piano and other acoustic
voices are so realistic. One voice may have as many as 64 partials and the total aggregate may be up to 240 partials. When
the polyphony exceeds this limit, individual partials (marked as optional in the sound models) are stolen, rather than whole
notes.
What about the sounds?
The Kurzweil 150FS comes with 27 Kurzweil-quality acoustic and electronic instrument voices (plus ramp, square and sine
waves), including an incredible acoustic piano, and three expansion sockets for adding more sound blocks as they become
available. The Sound Modeling Program, a standard feature of the 150FS, enables the musician to develop original sounds.
Is it the same piano sound that’s in the Kurzweil 250?
The piano sound is different but just as high quality. It has certain additional features due to the technology used to create the
sound. For example, there’s more change in timbre from soft to loud and more change in the sound as it decays -- there is no
looping as with samplers. There are actually 8 timbre levels in the piano and 5-8 in the other sounds (except the organs).
How do I use the 150FS?
The instrument comes with 93 preset programs for accessing the instrument voices alone or in combinations of splits and
layers. In addition, a simple front panel interface allows you to create and store your own preset programs.
What kind of programs?
You can split the keyboard into two or three regions and define up to seven sound layers in each region. Each sound layer
can select a different instrument voice and can be separately tuned, transposed and balanced. For example, you can put the
acoustic bass on the left side and have piano layered with guitar on the right. Or you can make a great twelve string guitar
sound using two guitar layers with one transposed up an octave and slightly detuned.
Can I use the 150FS with my Kurzweil 250 to reduce channel stealing?
The 150FS is a fine complement to a MIDI setup that includes a Kurzweil 250. Nevertheless, the 150FS will not increase the
number of channels available for your K250 sounds.
What else can I do?
Each sound layer can be timbre shifted (which alters the harmonic content of the sound). You can also control how effects
such as pitch bend, chorusing, vibrato and graphic equalization are applied.
What’s timbre shift?
Timbre ShiftTM is an effect that alters the harmonic content of a sound. It is a combination of transposition in one direction
with an equal amount of pitch shift in the opposite direction. For example, with one octave of timbre shift, when you play
middle C, the sound you get has the harmonic content of the C an octave below, but played at the pitch of middle C.
