Aly James Lab VSDS-X SIMMONS DRUMS EXTENDED VST User manual

VSDSX
SIMMONS SDS-V EXTENDED DRUMS
www.alyjameslab.com
USER MANUAL 2.0
BY
Aly James
©2014-2015 ALYJAMESLAB

TABLE OF CONTENTS
INTRODUCTION............................................................................................................................. 3
INSTALLATION............................................................................................................................... 6
CONTROL PANELS ......................................................................................................................... 9
THE SDS-V....................................................................................................................................11
FULL MODE..................................................................................................................................17
TRIGGERS ....................................................................................................................................19
BASS VOICE..................................................................................................................................21
SNAREVOICE...............................................................................................................................22
TOM VOICES................................................................................................................................23
HIHAT & CYMBAL VOICES .............................................................................................................24
SETTINGS.....................................................................................................................................27
EPROM LOADING.........................................................................................................................30
PRESETS IMPORT / EXPORT...........................................................................................................32
MIDI AUTOMATION......................................................................................................................33
VERSION 2 ADDITIONAL INFO .......................................................................................................34
LINKS...........................................................................................................................................38
DISCLAIMER & LICENCE AGREEMENT ............................................................................................39

INTRODUCTION
My name is Aly James;
French funky musician, composer and creator of strange musical DIY devices
and software.
I was planning for a long time to make an accurate Simmons VST dedicating
to the 1st Great Analog drum synth in History, mainly because I have never
been happy with packs of samples coming from different recording chains,
lack of control over the pitch and source mixing and all that makes the unique
sound of that legendary drum brain invented by Dave Simmons.
You probably already heard aSimmons drumsynth without even knowing it... wondering what was
used to produce that huge drum sound?
The Simmons hexagonal shaped electronicdrums were all overthe place, on countless records and
live shows during the 80s, used by artists and bands like Genesis, King Crimson, Jean Michel Jarre,
Prince, Herbie Hancock, Pink Floyd etc... The sound was not especially realistic but it was not the
goal...the goal was to be huge and versatile. Invented by Dave Simmons, the most famous drum
brain called the SDSV or SDS5 was a drum synthesizer, bringing synthesis into the drummer hands.
Often used abusively to generate only thosepewww pewww tom tom sounds, the SDSV module
produced a wide range of sounds. With a great punch and sensitivity, a truly unique and cult sound,
it can be used for almost everything. The SDSV successor called SDS7 bring some digital low-fi
samples in the game and a bunch of additional features like bend direction orFM modulation for a
broader range of possible sounds.
The SDSV is an historical piece of gearthat has a place in the sound of the 80s and is still used today
as a secret weapon. Only around 5000 of these things are out there so don'tcount on finding a
working one easily orfor cheap. The machine was made by a true innovatorthat later unfortunately
lost his Simmons Company (I think he got is name back!). As there were no accurate VST for this
legend out there...
I had to make the VSDSX! I have alsotakensome freedomtotweak a bit the behavior of the original
systemtomake it evenmore versatile.
________________________________________________________________________________

I grew up listening to a lot of 80s music, the Simmons drum sound was preeminent and was a huge
part of the sound. The SDS-V was mostly analog, a secret tool the make some drum layeringwith
real drums or drummachines like the Linn LM-1 or DMX…the clever design allows a great range of
drum sounds from real sounding drums to sci-fi and experimental sounds.
Lots of real drummers praise the Simmons Kits, even today! More recently the electronicscene has
also embraced again analog and the Simmons drums are highly praised. The special sample based
hihatand cymbals are unique and you will discover why in this manual.
The coolest thing was that raw analog character and the awesome punch the brains delivered. All of
these have been studied and I have tried to reproduce accurately the sound generation. I think the
result is pretty nice, so let’s bring back the Simmons sound together! VSDSX gives you even more
control overthe sound generation than the real Simmons brains.
It is based on the SDS-V but also mixes some features from SDS3, SDS7, and SDS1.
This emulation is based on reverse engineering and old datasheets; it uses a C++ custom core with
modeled Analog circuitry, Oscillators, Counters, OPAMPs & Filters.
Since Version 2.0 a new CLAP voice has been added, closely based on the mighty Simmons Digital
ClapTrap.
________________________________________________________________________________
Thanks to all the nice people that started to use VSDSX and support my projects and to proud
owners of original Simmons Units who have sent me someof their lovely machine.

A special thanks to Dave Simmons (Simmons drums Creator) & Wolfgang Stoelzle
(simmonsmuseum.com)
Mainly,
VSDSX can be triggered via MIDI following mostly the GM MIDI Drums mapping.
Each trigger will engage some envelope generators that will act on different part of the
circuit. The output is amplified by an OPAMP and will be filtered in some way differently
depending on the volume; the analog behavior emulation will reproduce the soft and hard
clipping when pushed hard.
Each voice has its own knobs that will control all the parameters of the sound generation,
Bass, Snare, Toms and Hihat/Cymbal are tuned differently.
One voice is EPROM based and can be loaded with compatible (.bin) images. This opens up
to any sample sounds Linn, DMX, Drumtracks etc… and even your own created EPROM
content (See EPROM Loading.)
Basic MIDI implementation:
MIDI IN:
VSDSX can receive any MIDI CH as main source for triggers.
It can be triggered with a standard MIDI Keyboard/Pads or even a MIDI Drum Kit.
The default mapping follows almost the same mapping as GM MIDI Standard.
Since version 2.0 you can now makea custom MIDI map, see version 2.0 section at the end.
Bass – MIDI notes 35, 36
Cymbal – MIDI note 51, 52
Snare – MIDI notes 38, 40
EPROM – MIDI note 55, 56
Tom High – MIDI notes 48, 50
Clap – MIDI note 37, 39
Tom Med – MIDI notes 45, 47
Tom Low – MIDI note 41,43
Hihat Closed – MIDI notes 42, 44
Hihat Open – MIDI note 46

INSTALLATION
COMPATIBILITY
Windows 7 to 10. 64bit Host (DAW) VST2 VST3
Mac OSX Snow leopard to Mojave 64bit host AudioUnits (AU)
INSTALL WINDOWS
1.Decompress the downloaded zip archive file
2. Run the VSDSX Installer
3. Load it in your DAW (rescan plugins if needed)
INSTALL MAC
1.Decompress the downloaded archive file
2. Copy VSDSX.component (AU) into the official default AudioUnits folder
/Library/Audio/Plug-Ins/Components/ (AU)
3. Copy VSDSX presetsfolder into Library/Audio/Presets/ or User/Library/Audio/Presets/
Note that the /Library folderis sometimes a hidden folder (search forhow tomake it visible)
4. Load the plugin in yourDAW (rescan plugins if needed, you may have to reboot once to make
it validated)

State of VSDSX current features
WIN 32 VST runs on 32/64Bit Systems and it is multicore compatible.
HIGH QUALITY GUI
(Different panels forcontrols etc...)
INSTANT UPDATE FOR ALL CONTROLS
FULL MIDI AUTOMATION
With midi learn(rightclickto assignMIDI)
ANALOG MODELED OSCILLATOR
The special tone characterof the drum synth is mainly caused by the raw analog waveform
generation and by the circuitry itself, it generate harmonics that are normally not present in an ideal
triangle waveform, VSDSX emulates thatbehaviorand also models the analog clipping that occurs
when pushed hard. You can also switch to a clean mode which will behavelike an ideal system
without OPAMP bandwidth limitation (more highs). These features alone offer a great versatility for
sound design.
NOISE GENERATOR CIRCUITRY TWEAKING
The sound source of the drum synth was mainly a mix between atriangle oscillator and a transistor
based noise generator. The way it was initially connected could be tuned formore orless frequency
content. Each voice have different configuration and VSDSX offers user control over the internal
noise filtering (especially usefulon the snare voice card).
A lots of the circuitry parameters can also be fine-tuned, CV and VCA response, Trigger types (that
will mostly impact the click attack generatortime) etc.
SSM2044 Filters

The noise source was filtered by an SSM2044 low pass filter chip, the filteracts on the noise and
clicks part and behaves differently dependingon the voice, on bass & toms the resonance resistor
was usually set to no resonance, but this can be tweaked inside the VSDSX if you want.
PITCH BENDING & SDS7 LFO FM modulation
One of the obvious things that must be there in a drum synthesizer is apitch envelope to simulate
the behavior of real drums. The SDSV module featured a bending down effect that can be set to
more or less amount of bending. VSDSX also features a bend up option and an optional FM
modulation taken fromthe SDS7module.
SEPARATE OUTPUTS
The SDSV have separate outputs forevery voices and so as the VSDSX.
You can choose fromALL to 1 Stereo Channel or Separate Channels for each voice.
TRIGGER SENSITIVITY CONTROL & VELOCITY
The drum synth is highly sensitive to the power with which a pad or a key is hit, VSDSX gives
independent access to sensitivity tuning for each voice, pitch of the tone, VCF cutoff, click trigger
etc...You can also disable the volumevelocity tracking and only set a pitch sensitivity which gives
access to a similarfeature than the "run generator" found in certain Simmons Systems.
GUI & AUTOMATION
The GUI features all the SDSV controls (with the same weird naming :) ) but can also give access to a
full module display with more in depth controls, most of the parameters can be MIDI learned and
controlled by an external MIDI Hardware or automation.
LOADING EXTERNAL EPROMS DATA
The VSDSX provides one voice which is EPROMbased (like SDS1or SDS7) the imported sample will
benefit from the bend and noise mixing featurewith that crunchy 8bit sound. Load your own custom
made EPROM image. EPROM format is the same as VProm (Ulaw Companded) foreasy compatibility
betweensoftware’s.
Since V2 you can also select Linear PCM which is the format for most of the published Simmons
EPROMs

LOAD & SAVE FULL PATCH & BANKS in many formats
CONTROL PANELS
Overview
VSDSX GUI INTERFACE is pretty straight forward; it stores the different parameters on different
panels.
The main interface let you select the voice you want to edit, for each voice you have those basic
controls:
The SENSITIVITY controls let you fine tune how the trigger velocity will affect the sound. The pitch
setting will act on the tone pitch from 0 to one octave, the volume velocity control can be set to off
independently and the attack setting will affect the short pitch pulse of the tone. (See Triggers)
The NOISE knob will set the Noise VCF cutoff frequency (it works differently for Hihat and Cymbal).
Note that it also affects the click sound as it is generated from the filtered noise source.
The TONE knob will set the base tone VCO frequency.
The BEND knob will set the bend amount applied to the tone pitch and VCF cutoff (not on snare). A
push button will invert the envelope generator CV to produce a bend up or down. The bend down
will start from the base frequency; the bend up will start very low and reach the bend frequency.
The DECAY knob will set the decay time of the sound envelope, it also applies to the VCF cutoff
excepted for the snare. The VCA response switch can change the CV type from the natural
exponential type (default) to a linear CV type.
The NOISE TONE mixer knob will mix the noise generator with the VCO accordingly.
The CLICK knob will mix the sound body (noise + VCO) with the short click sound accordingly (the
cymbal CLICK part is a bit different and made from cross-modulation between oscillators).
PANELS:
FULL MODULE: Will switch all voices to the full module view.

MULTI OUT: Will set the VST to multiple outputs configuration.
This will route all the voices to a separate outputlabeled with the voicename. You have to enable
the multiple outputs in your DAW. Each DAW has its way of doing it but it is generally straight
forward. The multiple outputs let you MIX easily the VSDSX voices inyourDAWas you will have a
plain channel strip foreach one.
OPEN SETS: Access to global configuration panel. It Controls, SSM2044 velocity affect, CV curves,
Optional modulation routing, Custom OSC mode and sound emulation modes (CLEAN or ANALOG).
EPROM Load custom: Access to the EPROM loading panel (only on the PROM voice)

Right click on a knob, button or slider will open a midi learn assign menu. Ctrl click + moveallow fine
tuning.
THE SDS-V

The SDS-V usually comes with a basic Bass, Snare + 3 Toms configuration but some lucky ones had
the hihat and cymbal modules.

If you look at these circuit diagrams you can see how the signal flows, basically the trigger will engage
envelopegenerators that will trigger the VCAs which will shape the noise generator, click and tone
VCO. The click itself is composed of the same filtered noise source.
Let’s look at the noise generator…
NOISE GENERATOR
It is based on classic transistor noise amplification (transistor + OPAMP) with a special thing, the
twisted wires...

It is called a gimmick capacitor, used to get a very small pico-farad capacitance and it is here in place
of a proper compensation capacitor on the op amp. It seems to let one be able to 'tune' the noise
easily, this is available to tweak in VSDSX as the HPF knob. It lets you filter out some of the noise
generatorfrequencies and is nice to produce a fullernoise sound, the SNARE in VSDSX have an extra
setting called FULL NOISE which will brings all of the noise generator frequencies.
THE SSM2044 VCF
The iconic Curtis chip SSM2044 (but also low cost) low pass filterwas used to filter the noise in the
SDS-V, the resonance can be tweaked but never in a big amount and you will not reach self-
oscillation on the SDS-V. This is the type of filterthat will not maintain the gain around the cutoff
resonance, so you will lose the bottomend. The frequency CV of the filterwillbe affected by the
envelopeand the trigger velocity, the noise will get duller as the sound decay. The snare is connected
differently and the envelope will notaffectthe frequency CV (which is more like a real snare).
THE VCO

The raw analog VCO triangularoutput get filtered by a basic RC circuit which form a low pass filter at
338.6Hz.
This filtering is only applied in VSDSX when you are in ANALOG mode.
ANALOG SOUND
The nature of analog is that every part of the circuitry will influence the other.

One of the main things that get affected is the sound harmonics and distortion.
VSDSX lets you switch between a CLEAN (read ideal mode) and ANALOG (harmonics and filtering)
The nature of the tone VCO will be affected by this setting, especially because an ideal triangle wave
contains only odd harmonics, it has a characteristicsound, similar to a square wave. When in analog
mode, different harmonics will be introduced; included even ones and the sound characteristic will
change a bit.
The graphicshows the differencesbetween clean (ideal triangle) and analog
.
The analog clipping also happens on CLEAN mode and will affect the sound depending on the voice
volume. Note thatthe more you mix CLICK with the sound body, the less volume the sound body will
have. If you set the NOISE TONE mix to full body, no click the volume will increase significantly and
you might reach clipping earlier. The analog clipping is pretty nice and can bring some punch and
presence to the sound, it depends what you are after.
This graphic shows the waveform from really clipped to none.

The volume can get pretty high so be sure to reduce your DAW channel volume to keep plenty of
headroom.
FULL MODE

The Full mode gives you access to all the fine tuning controls of the voice card.
•VOL: Set the general volume of the voice, can reach analog clipping if pushed hard.

•HPF: This setting Controls the internal filtering of the noise generator, usually set to high
excepted for snare, you can tune this parameter like you want.
•RES: This is the SSM2044 VCF lowpass resonance, usually set to none on SDS-V, excepted for
snare; you can tune this parameter like you want.
•CLICK Trigger Shape: This is useful to emulate different type of triggerCV, Simmons pads
generates a richer trigger pulse than sequencer CV forexample. This willaffect the length of
the click; this parameter ranges from 78ms to 315ms. The reset button will restore factory
setting.
•MOD amount: This is the a Frequency Modulation amount, an LFO is available per voice (like
a super SDS3) the LFO can be set to a triangular or square output shape, the modulation is
applied to the VCO pitch (note that the snare has an additional switch which let you
additionally route the modulation to the VCF, in this case this is a pre-fader modulation ( full
modulation is sent regardless of the mod amount)
•RATE: This controls the speed of the LFO, the divide switch will set the frequency to a low
range or a high range.
All these parameters can really shape the sound in many ways; it is up to you to experiment!
TRIGGERS