Dave Smith Instruments Tetra Desktop Synthesizer ModuleTetra is our next-generation analog poly synth. Tetra takes the
award-winning sound and features of Mopho, multiplies them by four, and
packs them in a box less than half an inch larger!
Tetra has multiple personalities. It is a four-voice, analog poly synth,
a sort of “mini Prophet.” It's a four-part, multitimbral synth with
separate outputs, essentially four Mophos in one very compact box. And
it’s a voice expander for other Tetras or the Prophet ’08
Outside the Box
Physically, Tetra is similar to Mopho, with four assignable parameter
controls per program and a row of controls dedicated to the most
commonly used performance parameters. All of the parameters can be
accessed from the front panel and Tetra is fully programmable. A free,
downloadable editor is available for Mac OS and Windows to facilitate
more comprehensive tweaking.
Most of the rotary controls are detented encoders, but Cutoff and
Resonance are potentiometers, allowing full sweeps with a single turn.
The Push It button is a manual trigger to play notes and latch sequences
on without the need for a MIDI controller.
Audio is output in mono, stereo, or per voice, via the four audio output
jacks. There is also a headphone out. MIDI communication is by standard
MIDI in and out jacks or USB. Poly Chain Out is a special, dedicated
MIDI output to chain multiple instruments for increased polyphony.
Under the Hood
The voice architecture is based on the Prophet '08, but with the
addition of a sub-octave generator for each oscillator and a fully
programmable feedback loop for each voice. That breaks down to two DCOs,
a resonant low-pass filter, three DADSR envelope generators, four LFOS,
deep modulation routing, an arpeggiator, and a 16 x 4 analog-style step
sequencer per voice. Feedback is capable of producing effects ranging
from mild distortion to fairly extreme harmonic instability. (That's a
good thing.) The possibilities are nearly endless. And the audio signal
path is 100% analog.
Tetra a la Mode
In Program Mode Tetra is a four-voice, polyphonic synthesizer with four
banks of 128 programs. As with the Prophet '08, each program contains
two layers—each layer is essentially a separate patch—that can be used
to create keyboard splits or stacked sounds. Banks 1 and 2 are the
Prophet '08 factory programs; banks 3 and 4 are a combination of Mopho
and new programs.
In Combo Mode, a different program can be assigned to each of the four
voices. Combos can be used for mammoth unison patches or for triggering
up to four different 16 x 4 sequences—each with its own
program—simultaneously. Combos can also be used to create
"modular-style" polyphonic patches, where each voice plays a different
program, with a slight variation on the same sound or even a drastically
In Multi Mode, Tetra becomes a multitimbral sound module capable of
playing four monophonic parts on four MIDI channels, with separate
outputs for each voice. Coupled with a MIDI sequencer and DAW, Tetra can
play complex arrangements or analog drum parts with each part
individually processed and recorded to its own track.
This One Goes to 12...and 16
Up to four Tetras can be poly chained for eight, twelve, or sixteen
voices total. When used with a Prophet '08, up to two Tetras can be poly
chained for a maximum of sixteen voices. In addition, the Prophet's
front panel controls map directly to almost all of Tetra's parameters,
so the Prophet acts as a programmer and control surface. And a Mopho can
be connected to Tetra's Poly Chain Out for five-voice operation.