Roland MT-32
Multi-Timbre Sound Module (1987)

 

A consumer module from more professional series D-10 / D-20/ D-5/ D-110 synthesizers based on LA Synthesis (Linear Arithmetic synthesis) which flagship is the classic Roland D50.

Today the MT32 is mostly famous as THE music expander for pc gamers during the 90'. There are two motherboard revisions known as "OLD" and "NEW" with some minor differences on the circuit board.

MODULE Main panel features a 10 x 2 lines display, a Midi activity led, 10 buttons and a potentiometer for volume settings.

Rear panel terminal connectors:
- Midi interface
- main signal out
- headphones out (only in second release).

Power supply standard 9V PSU with -)+ polarity 650 mA.

 

TECH main CPU 16 bits intel I8095 (or 8098) handles 32 voices polyphony based on LA synthesis. Linear Arithmetic is not like a standard wavetable synthesizer: the sound generation is based on very short attack PCM transients for limiting expensive (at the time) memory usage. Psychoacoustic facts demonstrate that the attack segment is the most important part for the sound identification by human ear. MT 32 DAC is a standard 16 bits IC Burr Brown PCM54HP same found on mighty D50.

L.A WG Wave Generator is a mix of 2 syntheses:
- PCM wavetable (1)
- Digitally generated basic waveforms (2)






PCM WAVETABLE the WG handles a non-expandable 512 kb ROM wavetable (sampled at 32 kHz ) that contains 128 waves organized into 3 main categories:
- transient PCM acoustic
- transient PCM spectral loops
- transient PCM "normal" loops






DIGITALLY GENERATED WAVEFORMS is a kind of primitive V.A (virtual analog synthesis) able to generate 2 kind of classic waveforms: sawtooth + pulse which relative pulse width can be changed or directly assigned to a keyfollower.

HEAR pulse width range

STRUCTURE HIERARCHY the minimal synthesis part is the PARTIAL, then up to 4 PARTIALS make a TIMBRE. In the TIMBRE, the PARTIALS are combined in 2 pairs only in this way:
- 1 + 2
- 3 + 4.

Each partial features 3 main parameters:
- volume level
- pitch coarse / fine amount
- pitch keyfollow mode (from -50 to + 50%).

ALGORITHMS the WG combines partial synthesis elements with a digital ring modulator in 13 possible pathways or so-called algorithms split into 3 categories (check out colors below: 1-7 blue, 8-9 green, 10-13 red).

Structure Partial 1 Partial 2 Combination of 2 partials diagram 1 S S mix partial 1-2 2 S S mix partial 1 + Ring modulator 3 P S mix partial 1-2 4 P S mix partial 1 + ring modulator 5 S P mix partial 1 + ring modulator 6 P P mix partial 1-2 (mo 7 P P mix partial 1-2 + ring modulator 8 S S each partial is send to left right 9 P P each partial is send to left right 10* S S partial are ringmodulated then out 11* P S partial are ringmodulated then out 12* S P partial are ringmodulated then out 13* P P partial are ringmodulated then out

(p= pcm sample / s= digitally generated wave)
* in ringmodulation mode, the first partial defines the pitch while second one is the harmonic content.

 

 

PERFORMANCE system handles 8 parts + rhythm and some functions:
- 4 poly modes with different voice priority assignment
- individual volume / panning
- reverb on/off
- bender range
- fine tuning + semitones shift.

FILTER a digital 4-poles resonant lowpass filter only for the "S" synthesis: cutoff is quantised to 100 levels, assignable to velocity with keyfollow mode and breakpoint.

HEAR digital filter cutoff with Q resonance

 

ENVELOPE 3 EGs for each partial:
- EG AMP: 5 segments ADSR + 5 times
- EG filter: 5 segments ADSR + 5 times (only for S synthesis)
- EG pitch: 5 segments ADSR + 5 times.
The EG amp can be also assigned to velocity or to keyfollow mode (depends on note).

 

LFO a single triangle-shapped modulatorfor the WG pitch (filter? PWM? shame!) with variable depth, frequency and global amount to pitch bender.

HEAR the LFO modulator

EFFECT a dedicated IC HG61H20R36F (at IC17) manages some simple digital reverbs with adjustable duration and intensity (only by sysex).

4 reverbs algorithms: room, hall, plate and tap-delay.

 

MEMORY is volatile and holds:
- 128 ROM patches (dowload full patchlist)
- 64 RAM slots.


VIEW High-res motherboard pic / DAC PCM54 HP / CPU I8095 /

 

MIDI limited CC controls (modulation, hold, pan, expression) but full SYSEX implementation.
For some absurd reason Midi and MT-32 channels are not matched: 1-8 are assigned to MIDI channels 2-9, however it is possible to change it from direct panel.
TIP: This unit is NOT compliant to GS/GM Midi protocol, but there are some third-part applications are able to make an approximative conversion GM->MT example :
GS non-converted / GS converted

 

 

EDIT it is NOT possible to deeply edit MT-32 from panel, consequently an external programmer is required:
- Soundquest (PC/MC commercial) PIC
- DR.T's MT-32 (Atari ST/ old PC dos, out of business) PIC
- LA synth (old PC out of business)
- JSynthLib (Java, free, out of business )
- MT32 sound designer (Atari ST) PIC

 

 

MODIFICATIONS some custom modification:
- Classic experimental modification is the CIRCUIT BENDING
- The most famous mods were officially done by Real-World music for the Mk1 model including: sound quality improvement, battery backup for sounds, waveform polarity debug, some extra front parameters, new reverb modes and individual analog Aux outs.

 

Mt 32 circuit bending VIDEO.	Real world DAC modification document download

FUN FACT MT32 is indeed a strange synth case: today it is still praised by the retro-gamers as the unit ihas been a standard on the games musics from the nineties when connected by Midi to PC some AMIGA computers even ATARI ST.

HEAR some MT32 famous sounds track: Ultima7 - Space quest 3 - Ultima Underworld - Castle Dr Brain DOWNLOAD full Sierra games MIDI soundtrack collection especially designed for MT32.

RELATED FAMILY:

D50 the best and the most complex of the LA series even if the wavetables is smaller (128kb) . The Filter and LFO section are more flexible and less strict than D10/MT structure.No drums but better FX. Rackmount version is D-550 D10 61 keys synth same structure as MT32, very similar but fully programmable from panel. Also a version with floppy drive (D-20) a budget version (D-5) and a rackmount version (D-110) VIDEO LAPC-I is a sound card module for old ISA PC slots. It is compatible with MT32 and CM32L VIDEO CM32L (CM COMPTER MUSIC) a kind of MT32 repackage with an extra array of waveforms. VIDEO NB: the CM32P is not an LA, but full PCM based on U-20 synthesis CM64 is a mix of CM32L + CM32P VIDEO CM500 expanded CM64 based on CM32L + CM32P+ CM300 (GS/GM compliant devices) VIDEO MT100 is a MT-32 (new board) with internal sequencer and (ugly) quick disk drive VIDEO

 

 

VST PLUGIN / SAMPLED VERSION some free samples, soundfont and a kind of virtual (not VST) emulator:

	name	note
	-Music machines - MT32 SOUNDFONT	<-- Download FREE sample set
	MUNT emulator FREE VST This utility creates a virtual MT32 Midi port. It *should* needs original MT 32 ROM + WAVETABLE dump	Some latency: great for games, less for playing on Midi. Some test I made: Original MT32 DUNE game VS. MUNT version

 

 

AUDIO DEMO

Track 100% MT32 (no fx, overdub) Soundtrack: ultima VII game recording Soundtrack: Castle Dr brain Soundtrack: Space quest 3 Sountrack: Ultima underworld piano: early piano piano: kinda rhodes EP organ: lounge organ trovajoli synth: fatty sound synth: TB-303 synth: Analog moog pad: worried pad: ambient noises 2 pad: ambient noises (2+2 partials) pad: resonant pad flute: recorder bell: falling down string: pizzicato

perc: taiko war drums perc: Timpani perc: drum kit Fx: useless telephone FX: Ring modulator rhythm Comparison: u7* by mt32 Comparison: u7* by MV30** (mt32 emulation) track: factory demo 1 (from NEW board) track: factory demo 2 track: factory demo 3 tracK: factory demo 4 track: factory demo 5 Track recovered from planet zero   test: 4 minutes of random sounds test: Resonant filter test: Pulse width range test: LFO test: ring modulator

*Roland MV-30 (1990) with a special MT32 emulation mode.

VIDEO SELECTION Ultima VI Guybrush mt32 another hit from the past:day of the tentacle

 

 

MANUAL

SERVICE MANUAL (NEW VERSION)

original brochure

original advert

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