The number of different timbres (instruments) a synthesizer can play at a time. Some synthesizers are polyphonic but only monotimbral - ie they can play several sounds but only in the same instrument....
Multimoog
"A fine example of sensitive playing and a sensitive synth, the Multimoog is one of the
great live mono synths, stable enough to be practical and with control spaced widely
enough apart to invite realtime twiddling. The Multimoog has a mod wheel, a pitch
ribbon, an aftertouch sensitive keyboard and a pepper-pot of a real panel, on which you
find, among other things, glide and modulation footswitches and jacks for CV control
over volume and filter cutoff. The VCF pedal was, in fact, used to great effect by [Steve]
Winwood..."
"The panel is encouragingly sparse for the vervous novice synthesist. The Multimoog is
actuallyan upgrade of the Micromoog but with two oscillators. The oscillators choose
their waveforms from a smooth-running control knob that moves from a sawtooth wave
through a square wave and into a narrow pulse. This is unusual, and although it makes
replicating precise sounds more dificult, well, who wants to recreate on an instrument
like this? Just create! Oscillator A also has an interval knob that allows it to be pitched
independently (up a fifth) from Osc. B. Meanwhile Osc. B can throw a sub-oscilator
square wave into the procedings at one or two octaves below set pitch, which is brilliant
for real subteranean bass. There is some streamlining though: Overall oscillator pitch,
which can be set from 32' to 2' or 'wide' (pitching the oscillator way out of earshot at
either end of the audio spectrum), is a shared control between the two oscillators, and
their relative balance is set by just one control knob. Noise is an additional sound
source that can be mixed in with the tuned oscillators.
"Filtering is a classic Moog 24dB/oct lowpass with cutoff frequency and resonance
(here, as ever, called 'emphasis') controls plus envelope generator amount control that
can function positively or negatively. The filter envelope is simple: ...[a knob for attack,
and a knob for release, and a switchable sustain. When the sustain is off the envelope
simple goes through the release as soon as the attack is complete, even if you are still
holding down the key.] ...Simple mease fast to set up and modify, but also limmited in
terms of precise filter movement.
"The amplifier envelope generator is similarly curtailed... There are some interesting
triggering and modulation options, including the monotimbral 'drone' (no one at Moog
ever had a clue what this parameter was for either. so don't worry if you are left puzzled
at this point), filter modulation by oscillator B and the ability to "play" the filter without an
oscillator note in tow, which is excellent for whistly, spacey effects. Modulation sources
include a multiwaveform LFO with sample-and-hold, square and sine waveshapes that
can affect pitch or tone in amounts that can vary in speed and depth. The aftertouch
keyboard, which, at the time, was called 'force sensitive,' governs much the same range
of parameters as can be attached to the mod wheel (VCOs, VCF cutoff, sync) Though a
little heavy-fingered, this is a great feature to have on a set of sounds like this, where
human expression is very much the order of the day.
"And then there's the pitch ribbon. Pitch ribbons are making a comeback in the 1990s,
and this zero-inertia controller just begs to be stabbed at either for straight pitch-
bending, as Mr. Winwood displayed, or for the doubly dexterous, finger vibrato or even
trills. The pitch ribbon can be routed to either or both oscillators.
"Ribbon controllers are fairly expensive to manufacture, requiring extra circuitry and
adding another obvious potential failure point. However, Moog Music say that they have
a good stock of ribbon assemblies, as well as keyboards, in stock, so a unit whose
ribbon is frayed or torn is far from a write-off.
"While the construction of the Multimoog is not so lovingly lavish as that of the wooden-
cased Minimoog, it remains practical and tough. High, metal-edged sides protect the
panel hardware, and the whole construction is solid and built to last. I recall Moog
salespeople at the time of its release boasting they could (and indeed did) jump up and
down on units to prove their sturdiness.
"Instruments can look a bit battle-hardened, but on the whole they have stood the test of
time very well, physically and operationally. This is a simple monophonic, not quite
providing the timbral richness of a Minimoog, to be fair, but supremely playable and a lot
of fun."