Inside the V-Synth, part 2

In Part 1 of this series, we looked at the oscillator types and functions of the V-Synth. Now, let's look at the rest of the voice signal chain.

Structures

Recall that the V allows, for a given patch, a choice of one of three "structures", which determines which order the processing elements are placed in. This concept is a carryover from earlier Roland digital synths; given the limitations of the technology used in those synths, it was necessary to use structures in order for the synth to determine the DSP resources needed for a given patch, and to provide for certain cross-element modulation functions such as ring modulation. However, the V is smart enough to allocate DSP resources dynamically, and it provides other means of modulation. So the only thing the structure selection on the V really does is determine where the COSM filters are placed in the chain; everything else is the same in all three structures. Structure 1 places both of the filters in series after the oscillator modulation mixer. Structure 2 places COSM 1 in line after osc 1, ahead of the filter. Structure 3 places both COSM filters ahead of the mixer, one each in line with each of the two oscillators.  The diagram below illustrates them in the same configuration as the structure selection buttons on the panel (for some reason, I haven't been able to take a good picture of the actual buttons):

The Oscillator Modulation Mixer

The oscillator modulation mixer (usually referred to as the "mod" for short) combines the outputs of the two oscillators (one or both of which may have been processed by a COSM filter at this point, depending on the chosen structure). The mod takes care of all forms of modulation (except cross-modulation) in which one oscillator effects the other. The mod operates in one of four modes:

1. Add mode. This simply mixes the two signals.
2. Ring modulation mode. This allows osc 2 to amplitude-modulate osc 1 in any amount up to full balanced, or ring, modulation. (Recall that ring modulation is simply AM at 100% modulation.)
3. FM mode. This mode allows osc 2 to frequency-modulate osc 1. In Yamaha terms, this is only 2-op FM, so it may sound lame. However, recall that the canonical Yamaha FM system uses only sine waves, while the V allows any waveform to be used as either the carrier or the modulation. So very complex and bizarre results are easily (a bit too easily!) obtainable.
4. Oscillator sync mode. In this mode, osc 1 will sync to osc 2. Osc 2 must be a virtual analog waveform.

The COSM Filters

The "COSM" acronym is a Roland trademark which stands for Composite Object Sound Modeling. Basically, it's a set of software algorithms that implement all of the familiar analog filter types (high pass, low pass, bandpass, and notch), as well as a number of more complex types, physically modeled resonators and some other algorithms that either aren't actually filters or do things other than just filtering (such as compressors and guitar amp simulators). The complete list:

1. TVF -- "time-variant filter", a long-standing Roland-ism for the digital equivalent of your basic VCF. Lowpass, bandpass, highpass, notch, and "peak" (which I presume is a high-Q bandpass) are available, and you can select 1-, 2-, or 4-pole response.
2. Dynamic TVF, a filter whose cutoff frequency tracks the envelope of the input signal. Same options as above.
3. Dual filter. This allows you to put a lowpass and a highpass in series or in parallel, or put two bandpass filters in parallel.
4. TB Filter, which simulates the VCF of the famous/notorious TB-303 bass machine.
5. Sideband filter. This is basically a lowpass and a highpass arranged in a "back to back" configuration so that they create two passbands about a center notch. Useful for adding a sense of pitch to unpitched noises, and for picking out certain harmonic bands from an FM-generated signal. There are two of these, a first-order filter and a second-order filter.
6. A comb filter. This is the type of filtering produced by flangers.  It can also be used to creat formants.
7. A resonance simulation. This simulates the resonance of a hollow-bodied guitar. It can also simulate a banjo or resonator guitar (e.g., a Dobro) body.
8. Amp and speaker simulations.
9. Distortion and overdrive.
10. A wave shaper, which can alter and distort wave shapes in various ways.
11. A "lo-fi processor", which is actually a bit crusher (reduces the resolution of the samples), and downsampler (interpolates the samples down to a lower sampling rate).
12. A compressor and a limiter. These are interesting because they are actually part of the voice; like the other filter algorithms, they process each note separately. These can be very useful problem solvers. A typical problem when setting up patches with drastic filter settings is that some notes play much louder than others. If COSM 1 is used as a drastic filter in a patch, setting up COSM 2 as a compressor or limiter will smooth out the variations in loudness between different notes.
13. A frequency shifter. This duplicates an effect that was originally developed in analog form in the 1950s, but was seldom used because the necessary circuitry was expensive and difficult to keep in calibration. Unlike the more common pitch shifter, the frequency shifter does not maintain the harmonic relationships between overtones. Needless to say, it can produce some very strange effects.

Each COSM algorithm has its own set of tweakable parameters, which are denoted in the detailed descriptions in the manual as parameters #1 through #4 (or fewer if the filter type doesn't have that many). The parameters labeled #1 and #2 are always controllable via the "cutoff" and "resonance" knobs on the panel respectively. Generally, these will be, if not actually cutoff and resonance, something analagous. However, in the case of things like the distortion and overdrive types, it's not always obvious; you have to read the manual. All four of the numbered parameters can also be assigned to the control matrix, which means they can be controlled using any of the synth's performance controls and/or MIDI Continuous Controller messages; this will all be described in a future installment. As in the case of the oscillators, each COSM has its own LFO which can be assigned to almost any parameter, and most paramters have their own envelope generators.

The final voice component in the chain (in all three structures) is the TVA. This has its own envelope generator, which has sliders on the panel (of the dozens of envelope generators in the voice architecture, it's the only one that does). It's somewhat surprising that the envelope is a conventional ADSR, given that the JD-800 and some of the JX series synths had more sophisticated multi-segment envelopes. The TVA does have, like everything else, its own LFO.

In the next installment, we'll look at the V-Synth's onboard effects.

Inside the V-Synth, part 1

So, now that I've had a few hours with the V-Synth, I will pass myself off as an expert. Actually, I did spend a fair amount of time studying the manual and online material before the synth arrived, so I was able to get going on it pretty quickly.

Roots of the V-Synth

Considering that the V is a bit out in left field compared to most of Roland's other offerings over the last decade, the question can fairly be asked: where did this idea come from? The roots of it can be seen in the JD-800/990 offering from the early '90s. That was Roland's first serious attempt to design a digital synth that would be attractive to synth programmers and sound designers. However, at the time it was introduced, it did not sell well. Part of this was the timeframe in which it was introduced (the synth market had turned heavily to romplers at the time). However, the attempt at building a knob-per-parameter digital synth turned out to be intimidating to some customers, as well as making the unit physically large. And, in the end they still had to put the effects, MIDI, and system parameters in menus. It helped that the 800 had two displays which were fairly generous for their time, and the 990 had an even better multi-line text and graphics display (derived somewhat from the S-series of samplers). Despite the flaws, it was state-of-the-art for a digital synth user interface at the time.

Now, the V-Synth came about as a compilation of everything that Roland had learned about synthesis and signal processing since the JD-800 was designed. And that was quite a lot -- the Variphrase technology which allows treating time and pitch as independent variables, the improved sample encoding and storage technology, and the COSM modeling filters, to name a few. Someone within Roland obviously desired to take all this new technology and make a worthy successor to the JD-800. A problem arose immediately: goven the complexity of this new synth, it was simply impossible to attempt the knob-per-parameter approach. However, the designers didn't want to send the sound designer down a twisty little maze of menus (having learned their lesson on that from the D-50). So they tackled the problem three ways:

1) They provided a set of dedicated controls for the most commonly tweaked parameters, including the oscillator tuning, the filter cutoff/center frequency, the ADSR values, and LFO rates. They also provided buttons to turn each component and effect block on and off -- not so much for performance as for convenience in patch editing, where it often helps to turn off some things in order to hear the impact of changes in other areas. For everything else, they added a large touch screen which graphically displays all of the parameters for a particular functional block.

2) They added an extensive set of performance controls, including some unconventional ones. Of all the polysynths I've ever seen, only a few very expensive models such as the McLeyvier and the Hartmann Neuron approach this same territory in performance controls.

3) They created an extensive modulation matrix to map these controls, and incoming MIDI messages, to a large slate of real-time-modifiable parameters.

We'll get back to the performance controls in a later installment, because some of them are difficult to understand the function of until you are familiar with the synthesis architecture. For now, we'll stick to what makes the noise. To start the demystification process, note this: for all of its complexity, the V-synth is still a subtractive synthesis machine. There's no exotic synthesis method at work here; although the oscillators and filters are far advanced from your old Juno, they are still basically arranged in the classic VCO-VCF-VCA signal chain.

The Voice Architecture

Each V-synth patch can make use of two digital oscillators, two COSM filters, a time-variant amplifier (digital equivalent of a VCA), plus three effects blocks and a "mixer" which can combine the two oscillator signals in various ways. For each patch, one of three "structures" can be chosen; the structures differ in which the filters are placed with respect to the mixer. Structure 1 mixes the two unfiltered oscillators, and then flows the mixed signal through the two filters in series. Structure 2 places one filter on oscillator 1's output prior to the mixer, with the second one remaining after the mixer. Structure 3 places a filter after each oscillator and before the mixer.  The photo below shows the three groups of buttons which graphically illustrate which voice elements are active in the selected structure:

Control groups for the voice elements: top left, structure selection and element on/off buttons; top right, effects on/off; lower L to R: oscillators 1 and 2, COSM filters 1 and 2, TVA envelope.  

The Oscillators: PCM Mode

The oscillators allow a choice of three different modes: PCM, virtual analog, or external input. The PCM mode plays samples, as you might guess. The usual choices of looped or one-shot playback are available. The factory load comes with about 700 samples, but you can also add your own. There are two ways to do this. For some reason, it isn't often stated in reviews of this synth that it contains a full-up sampling capability, similar to the S-series samplers, which choices of triggering mode for sampling start/stop, loop point, compressing, normalizing, and trimming options. Resampling is also supported; a note can be played using the full capabilities of a patch, and the result captured as a new sample. In addition, the user can also set markers called "events" inside the sample. Events divide the sample into segments, which can be used to divide the sample across a range of keys, or to play in a mode where playback advances to the next segment each time another note is played. Samples can also be loaded into the synth using the USB connection. In the V's "external disk" mode, its internal patch and sample storage will appear as a removable disk on the computer that it is connected to. (Both Windows XP/Vista and Mac OSX are supported.) Samples are stored in the V as ordinary WAV files, and new ones can be added by simply moving or copying them to the mounted volume.

Before a sample can be used by the V, it must go through a process called "encoding". The encoding process supports the Variphrase capability; it creates a sort of map of pitch changes and variations in the sample. Four encoding algorithms are available, each of which works best on a particular type of source. (If you choose the wrong one, you may get weird pitch anomalies when you try to use the sample in a patch. But intentionally mis-encoding a sample might also be a useful way of creating chaos patches.) One particular algorithm, which works best on solo voice and instrument samples, will also analyze the sample for "formant" information (in other words, information about the resonances within the body of the instrument or the vocal tract of the singer), which can then be varied when the sample can be used in a patch to change the tonal character of the sample.

Once a sample is loaded and encoded, you can use it in a patch.  The patch parameters will allow you to set the loop mode, retune the sample, set up the Variphrase to treat the sample the way you want, and so on.  When playing in PCM mode, the Variphrase provides a number of tricks that allow you to treat pitch and time separately -- you can make time go slower and faster while pitch remains the same, or pitch bend without effecting playback speed, and so forth.  You can make the sample play in rhythm to an internal clock or an external MIDI clock, and you can make the sample play forwards or backwards as desired.  

Virtual Analog Mode

In the virtual analog mode, the usual analog waveforms are available: sine, square, pulse, sawtooth, ramp, white noise. These are probably computed rather than sampled waveforms. 

(Note: the 2.0 OS added a number of waveforms and significantly enhanced the virtual analog capability.  If you get a printed manual with a used V-Synth, it will probably describe the version 1.0 OS capability.  Download the revised manual from www.rolandus.com -- it's free.)   There are the usual waveforms that one expects from an analog VCO, including sine, square, pulse, triangle, white noise, and sawtooth, with variations -- a waveform labeled "Juno" is a digital simulation of a sawtooth wave from the Juno-60.  "LA-Saw" and LA-Square" are, as you might guess, re-creations of the sawtooth and square wave algorithms from the D-50.  There is the "supersaw" waveform which is all the rage in techno these days; it's a simulation of several stacked oscillators all generating sawtooth waves with slight pitch offsets.  Two waveforms are labeled "high quality" saw and square; I'm not yet sure what the difference is between these and the standard saw and square.  There are subtle tonal differences, but I'll have to put the scope on them sometime to see what the differences actually are.

The really intriguing types are the cross-modulation and the feedback oscillator.  Selecting X-mod on oscillator 1 causes osc 2 to cross-modulate it.  Since it still works even when osc 2 is a PCM waveform, very complex waveforms are obtainable.  The feedback oscillator uses some kind of iterative algorithm to create sounds that can sound like feedback through a guitar amp or PA system.  They can also sound like whistling, various wind instruments, a glass harmonica, or a variety of sounds that might usually be expected to come from an additive synth.  

A sub-oscillator can add a square wave at the  same pitch, or 1 or 2 octaves lower.  The sub-oscillator can be detuned.  There is also a parameter labeled "impact" which can add a spike to the start of the waveform to simulate a percussive attack.  

External Input Mode

Finally, the sound source can be an external input, via rear-panel jacks. This allows the V-synth to be used as a real-time processor for signals from other instruments. As an interesting example, one of the algorithms in the COSM filters is an amp simulator, complete with distortion, overdrive, and several speaker cab choices. You could use the V-synth as a rather unlikely guitar preamp! There's a gain control on the panel for external inputs, but I haven't yet tried it to see if it can interface directly with a guitar. Likely the inputs are low impedence, so if you wanted to actually do this trick, you'd probably still need a direct box or some such to prevent the synth's input from loading down the guitar pickups.  Do note that you still have to play a note on the keyboard (or via MIDI) in order for sound to come out!  

Oscillator Parameters and Modulations

There's the usual pitch tuning and keyboard tracking settings. Unfortunately, the very useful "stretched" and "shrunk" keyboard tracking options from the JD-800 aren't present. However, it does have 50% tracking so that playing quarter-tone scales is possible, as well as zero and negative tracking. One feature that did carry over from the JD-800 is the pitch randomization parameter, which can add a desired amount of pitch uncertainty to each note. Each oscillator has its own dedicated LFO, with the usual choices of waveforms. Keyboard tracking and the LFO can be assigned to nearly any parameter. For PCM waveforms, time is also a parameter that can track the keyboard and be modulated by the LFO! Remember, Variphrase makes pitch and time independent. Additionally, if the SOLO sample encoding mode was used on a PCM sample, formant becomes yet another parameter that can track the keyboard and be modulated by the LFO. And, every one of these parameters has its own ADSR envelope. Finally, and incredibly usefully, each oscillator has its own TVA (in addition to the TVA at the end of the patch signal chain), with a dedicated ADSR envelope of course. There's enough envelopes inside this synth to start a post office.

In Part 2 of this series, we'll look at the COSM filters, plus the oscillator mod mixer and the TVA.

Did ya miss me?

For the past two months, I've been in a major crunch at work, which is why I haven't posted. But in the meantime, I got a new toy! Here's a couple of glamor shots. The last one gives it away:

Yamaha TG33 rack mounted

Matrixsynth has up a post on the Yamaha TG33, which is basically a tabletop version of the SY22 keyboard.  It is possible, although a bit awkward, to rack mount the TG33.  Here it is:

The rack ears are apparently hard to find.  Where the ears fasten to the side of the synth, they provide two sets of holes so the synth can be mounted horizontally, as seen here, or tilted forwards at about 30 degrees.  Here is a close-up of the mounting:

It isn't possible to mount it vertically, and there's a reason why: the display, which is already at an angle, would be facing the floor.  As you can see, some space has to be left above the TG33 in order to see the display and reach the power switch, volume knob, and data entry knob.  And, unless it's near the top of the rack, you  have to leave some space under it also, because it obviously overhangs whatever is below it.  Nonetheless, it's still more convenient than having to find surface space for it.  

Vintage synths with reliability issues

Everyone who plays or collects vintage synths knows that it's a labor of love. Some are difficult to keep in tune; some contain parts that are hard to find replacements for, and some are just cranky and unpredictable. However, there are a few synths with known failure mechanisms to watch out for. The shame of it is, all of these are well-regarded for their sounds and playability. Still, there are things that owners and potential buyers should be aware of. Here's a guide to these problematic synths.

Roland Juno-106, MKS-30, and GR-700

Failure mechanism: The Roland 800017A VCF/VCA hybrid IC suffers from internal metal migration, which eventually causes internal shorts.



Failure signature: A voice crackles, cuts in and out, or continues to sound when no key is pressed. Rustling noises may be heard when playing or when no key is pressed. Less commonly, a filter may behave erratically or refuse to stay in calibration. Symptoms may get either better or worse as the synth warms up. On the Juno-106 or the MKS-30, in Poly 1 mode, every sixth note played exhibits the symptoms. On the GR-700 guitar synth, one particular string exhibits the symptoms.



Advice for buyers: If you can get access to the synth, power it up in test mode (or tuning mode for the GR-700)and test all six voices. Do this once when the synth is cold, and again after it has warmed up for about ten minutes. If you can't get access to the synth (e.g., an Ebay deal), insist that the seller disclose whether or not all six voices work and stand behind his word.



Advice for owners: Despite some Internet speculation, no one has managed to identify any particular date codes that will or won't fail. Owners are advised to stockpile a couple of spares. Currently 80017A's are going for about $65 US on Ebay. An alternative is to buy a broken 106 for parts; a used 106 with problems will often sell for less than the cost of a full set of 80017A's. Another alternative is a clone part. There are several available, but the one I recommend is the D80017 from Analog Renaissance. It's nearly the same size as the real thing, so it won't cause any clearance or heating problems inside the case, and the manufacturer claims that calibration trimming will be similar.



Difficulty of repair: Not difficult. Anyone with soldering skills should be able to do it. The board is clearly labeled as to which ICs go with which voices. For the Juno-106, see my previous post for the location and layout of the module board. For the MKS-30 and the GR-700 (which use the same board), see this page from Wayne Scott Jones.

Korg Polysix

Failure mechanism: A NiCad memory backup battery installed at the factory leaks onto the CPU board, eating the copper traces off the board and damaging the substrate.



Failure signature: Random behavior; panel buttons don't work, lights flash randomly, voices don't play. Or, the synth doesn't boot up at all. Note that serious damage can be done before the battery fails to the point where patch memory doesn't retain.



Advice for buyers: Ask the seller if the battery has been replaced and the CPU board inspected and/or repaired. If the answer is no, or if the seller doesn't know what you are talking about, don't buy unless you have a good tech or advanced electronics repair skills.



Advice for owners: If you don't know that your Polysix has been previously repaired and a lithium battery fitted, open it up and inspect the CPU board. This page from "The Old Crow" (Scott Rider) shows how to open the synth up and what to look for; it also contains the detailed repair procedure.



Difficulty of repair: Replacing the battery, in itself, is not difficult. However, by now, chances are that any Polysix that still has its original battery has suffered significant damage to the CPU board. The battery acid can be neutralized by cleaning the board with baking soda and water, but damaged board traces have to be identified and jumpered. It's a tedious job that requires some knowledge of the circuits, and advanced soldering skills.

Update: Commenter "steamy vicks" advises that the Kawai SX-240, and possibly also the SX-210, suffers from this same issue.

Rhodes Chroma Polaris

Failure mechanism: Ribbon cables which are molded into the membrane panel have been embrittled with age, and crack or split when moved or subject to vibration.



Failure signature: Some or all panel buttons don't work.



Advice for buyers: Frankly, unless you absolutely have to have one, or you are handy with electronics and you want something to experiment on, don't buy. If you do find one cheap, be aware that the Curtis IC's in the synth are probably worth more than the synth itself.



Advice for owners: Don't gig with your Polaris; in fact, don't move it at all if you can avoid it. Don't open up the synth unless you have to; opening it flexes the ribbon cables.



Difficulty of repair: Because the ribbon cables are one piece with the membrane panel, the easiest path of repair is to replace the whole membrane. This is not a difficult repair; the difficult part is finding a replacement. Here is a list of service centers from rhodeschroma.com, but it is my understanding that there aren't many Polaris panels left. And, be aware that any replacement panels that do exist are as old as the originals, and are likely to also have the embrittlement problem. Attempts to splice the ribbons back together usually fail because handling the ribbons cause them to crack further. In this thread from Harmony Central, a poster succeeded in soldering wires onto the end of the ribbon cable and connecting them to a bulkhead connector. However, as you can see from reading the thread, it was a very exacting job requiring, among other things, a temperature-controlled soldering iron. The best way to address the problem appears to be to just use a software editor and edit via MIDI. I've seen talk about designing a replacement panel using real switches, but I haven't found anyone who has actually done this.

Ensoniq Fizmo

Failure mechanism: The LM2940 voltage regulator on the DSP board shorts out and applies a high voltage to the DSP board, which fries the processors on the board.



Failure signature: The synth displays an "ESP" message in the display on power up, and won't play.



Advice for buyers: Ask the seller if the LM2940 has been replaced. If the answer is no, or if the seller doesn't know, do the following: (1) Make the seller assure you that the synth was working the last time it was powered up; (2) Instruct the seller to not power it up again before shipping, and (3) when you receive it, do not power it up until you inspect it and replace the regulator if necessary.



Advice for owners: If you don't know for sure that the regulator in your Fizmo has been replaced, do not power it up again until you have inspected it and replaced the regulator if necessary. If you do know that the regulator has been replaced, you're home free. Note that apparently some Fizmos had th regulator replaced at the factory before shipping; if the regulator in your Fizmo is something other than an LM2940, it's probably OK. Also note: There are a number of threads in various places speculating as to whether the factory supplied wall wart was responsible for these failures. This turned out to be not true, but there are Fizmos around with wall warts that don't supply enough current, which can cause erratic behavior. See Carbon111's page referenced below for more information.



Difficulty of repair: It depends on whether or not the LM2940 has failed. If the synth is still working, anyone who is handy with a soldering iron and a drill can replace the regulator. Carbon111 has an excellent page showing how to inspect the regulator, and it contains a link to a page with the detailed repair procedure. Unfortunately, if the regulator has failed and the synth is displaying the "DSP" error, repair is all but impossible. The DSP's are small-pitch surface mount parts that cannot be soldered or unsoldered without specialized equipment and advanced skills, and the cost of the repair would likely exceed the synth's market value. There is no known source for replacement DSP boards.

Who owns Minimoog serial #1001?

While looking into the lineage of an early-production Minimoog that was on Ebay last week, I got curious as to the whereabouts of Minimoog serial number 1001, the first production unit. We know this much: According to the Moog Archives, Mini #1001 was shipped to Walter Sear on November 19, 1970 (about a year before Bob sold the company to Musonics). Now, Walter was an interesting character, worthy of a future blog post himself. He was involved in marketing Moogs to the New York entertainment industry, and he also did some soundtrack work with synths (electronic scores were the new hip thing that every movie producer wanted in the early '70s). So he purchased several Minis out of the early production run; in addition to #1001, he was also the customer for units 1024, 1033, 1051, and 1062.

Given the number of units that passed through his hands, it wouldn't be a surprise if there was some swapping around of parts in a pinch. But I'm not sure this explains why there appear to be two Minis staking claim to being #1001 now. Contestant number one is in possession of the Eboard Museum in Austria. (I've provided a link to their page that describes most of their extensive collection; unfortunately it's all on one page and there appear to be no anchors in the page to link to. Scroll about 3/4 down.) Here's a photo from the page:

Contestant number two is from the Audities Foundation (which is also in possession of severa Mini prototypes). It should be noted that Audities does not itself claim that this is #1001; however, a Google search revealed three other Web sites (including Raymond Scott's site) claiming that it is. Here's a photo:

The main difference that jumps out at me is that black-on-white badge on the Emuseum one. I don't believe I've ever seen that on any other piece of Moog gear from the R.A. era. I'm not at all sure what to make of that. The other thing that I spot is that the switches near the pitch/mod wheels on the Emuseum one appear to be some kind of generic toggle switch, while the switches on the Audities one look like the switches used on the Model D prototype. Again, I don't at all know what to make of this.

Did Moog make two units numbered 1001? Possibly. It wouldn't be the first time that a company built a set of prototypes under a given set of serial numbers, and then used those numbers again at the beginning of the production run. If one of these is really a prototype, I'd bet on the Emuseum one, based on the fact that it looks rather well used, and the woodwork appears to be a different kind of wood or finish. But if it is a prototype, that raises the question of its lineage and how it got to be where it is now. Did Moog sell it to someone at some point? Did a Moog employee take it home? Did it get dragged from Trumansburg to Williamsville to Buffalo, get stuffed in a corner there, and then sit until the company went under and the assets were sold off? If so, it's kind of remarkable that it still exists at all.

Rhode Island

 A Statescape, done with the Boss DD-20 GigaDelay:

The Roland JD800 is the main synth.  Also used is the Oberheim Matrix-1000 for the bass parts, played via Studiologic MP-113 pedals.  This is a live performance with no editing or overdubs.

A higher-resolution audio file is available on the Source Code Web site here.