Comparisons of synthesizer models

Index:

* Synths organized by Class

A table listing hardware attributes

A table listing comparing features (under construction)

A philosophical note on why I believe Analog synths have made a comeback against digital in general.

2006 POLL from the synth DIY group about which synths are best in various categories.

Discussion of Terms used when we talk about synthesizer features. (eg. polyphony, vco)

A discussion of how keyboards interface with ciruitry in synthesizers.

How memory is commonly implemented in analog machines.

Notes on synth architecture and abbreviations used in describing features-

     Additive synthesis involves taking less harmonically laden sounds in general, and adding them together often with distinct envelopes and other modulations. The RMI Harmonic Synthesizer is the first of this type I know. Kurzweil and Kawai followed using digital technology about a decade later! But these renditions of the additive architecture were focused more around creating a sound by adding the harmonics you want at the time you want it. The Kawai K5 for instance had the ability in each patch to stack two 63 harmonic sets alongside or in linear order up to 126...and to assign each one to one of the 4 busses available for each half. Each buss had a 6 segment envelope and various modulations. Then the 'signal' went on to a digital filter on each half and a final "DDA" as they called it. A 7 segment envelope. Anyway that's only a small part of what the machine would do.
     Many machines had the ability to perform frequency modulation (Octave Cat for instance or modulars) long before the Yamaha synths appeared which were called "FM synthesizers". This is because their ability to do so was still more of a 'side show' to their overall design. The Cat is primarily still a subtractive synth architecture as it lacks dynamic control of the FM abilities it has save the player turning knobs. Machines may include other sound altering elements like this or ring modulation. But when the digital technologies came of age, programmers were now able to design machines that would emulate properties of nature that would be vastly complex and expensive to build with analog circuits.
     Yamaha's efforts created a totally new sound that sold like mad. Other manufacturers tried to follow with their own ideas. Casio with 'phase distortion'. Kawai and Kurzweil with their harmonic synths and so on. With software, there are no bounds basically. This may be a good thing in some ways...it may be bad in others. I find that the human spirit benefits most from contemplating real natural 'struggles'. In software, there is no such thing. Only the modelling thereof at best. Hearing actual work being done by electrons in a vast array of analog circuits though...there is nothing quite like it. -Bob

Monophonic single oscillator simple subtractive-
ARP Axxe, JEN SX-1000, JEN SX-2000, KORG 770, Moog Micromoog, Roland SH-3a, Roland SH-09, Siel Mono, Teisco/Kawai Synthesizer 100-F, Yamaha CS-5, Yamaha CS-10

Monophonic single oscillator subtractive with significant other features-
Octave Kitten, Roland SH-1, Roland SH-101

Monophonic single oscillator subtractive with digital control from presets-
ARP Pro-Soloist(DGX), ARP Explorer, Conn Electric Band, Elka Soloist 505, Korg M500 micro preset, Moog MinitMoog, Moog Satellite, Roland SH-1000, Roland S-2000, Yamaha SY-1, Yamaha SY-2

Monophonic dual oscillator simple subtractive-
Moog Prodigy, Moog Multimoog, Moog Rogue, Moog Taurus II, Roland SH-2, Yamaha CS-15

Monophonic dual oscillator subtractive with significant other features-
ARP Solus, Crumar DS series, Crumar Spirit, KORG MiniKorg700s, Moog MG-1, Moog Liberation, Oberheim 2-voice, Roland SH-5, SCI Pro One, Yamaha CS-15D, Korg Sigma (last two have presets and various controls), Yamaha CS-30 (around 80 knobs, 2VCF, 3ADSR)

Duophonic subtractive-
ARP Odyssey, Korg MaxiKorg 800DV, Moog Sonic 6, Octave Cat, Roland SH-7, Yamaha CS-40M

Monophonic dual oscillator with memory-
Moog Source, Oberheim OB-1, OSC Oscar, Roland ProMars MRS-2, Teisco/Kawai Synthesizer 110-F, Yamaha CS-20M

Monophonic three or four oscillator subtractive-
Moog Minimoog(3 vco wide range), Korg Mono/Poly (4 vco narrow range, but poly mode though only one SSM2044 VCF) Murom Aelita (3VCO driving divide down network, 1 LFO)

5-voice or less polyphonic subtractive-
Oberheim 4-Voice, Oberheim OBX(a)(4voice) Roland JP-4, SCI Prophet 5, Yamaha CS-50

6-voice polyphonic subtractive, one VCO/voice-
Akai AX-60, Akai AX-73, Korg PolySix, SCI Six-Trak, SCI MAX, SCI Multi-Trak

6-voice polyphonic subtractive, two VCO/voice-
Fender Chroma Polaris, Oberheim OBX(a)(6voice),Roland JP-6,SCI Prophet 600

6-voice polyphonic subtractive, three VCO/voice-
Moog Memorymoog

8-voice polyphonic subtractive, one VCO/voice-
SCI Split 8/Pro-8, Yamaha CS-60

8-voice or more polyphonic subtractive, two VCO/voice-
Oberheim OBX(a)(8voice), Oberheim OB-8, Oberheim Matrix 12, Rhodes Chroma(or 16voice 1 osc/voice),Roland JP-8, Roland MKS-80, SCI Prophet T8, Yamaha CS-80

6-voice polyphonic subtractive, one DCO/voice-
Roland Juno-6, Roland Juno-60, Roland Juno-106

6-voice polyphonic subtractive, two DCO/voice-
Crumar Bit One, Crumar Bit 01, Crumar Bit 99, Cheetah MS-6, Elka EK-22, Roland JX-3P/MKS-30, Roland JX-8P, Korg Poly 61(M), Oberheim Matrix 6, Siel DK-600/Opera 6,

8-voice polyphonic subtractive, one DCO/voice-
Kawai SX-210

8-voice polyphonic subtractive, two DCO/voice-
Elka Synthex, Akai AX-80, Kawai SX-240

Polyphonic DCO paraphonic VCF.-
Korg Poly800(II), Siel DK-70, Siel DK-80 (two DK-70's using only 6voice per chip instead of 8)

Bi-Timbral polyphonic subtractive analog with various DCO designs-
Roland JX-10, Roland MKS-70

Digital divider oscillators, Full Paraphonic analog-
Arp Solina String Ensemble, ARP Quartet, ARP Omni (1/2), Crumar Orchestrator, Crumar Performer, Korg Delta, Moog Opus 3, Roland RS-09, SCI Prelude, Siel Orchestrator (1/2), Yamaha SK series(combo synths; some containing 7 vc polysynth or monosynths)

Digital divider oscillators from VCO's, Full Polyphonic analog-
Korg Lambda, Korg PSS series, Moog Polymoog synth, Moog Polymoog keyboard

Digital divider oscillators, paraphonic analog with mono section-
Crumar DS-2,Crumar Composer, SCI Fugue, Yamaha SK30, SK50D

Divide down oscillator, polysynth hardware /combo synths-
Crumar Stratus (organ and 6 voice para-poly scheme), Crumar Trilogy (adds string section to Stratus)

Digital synths with analog filters (hybrids)-
Ensoniq ESQ-1, Ensoniq SQ-80, Kawai K3, Korg DW-6000, Korg DW-8000

Digital physical modelling; FM-
Yamaha DX series, Yamaha SY-22, Yamaha SY-55, Yamaha SY-77, Yamaha SY-99, Yamaha YS-200, Yamaha DSR-2000, Yamaha DS-55

Digital physical modelling; Additive-
Kawai K5, Kawai K5000, Kurzweil K150

Digital physical modelling; Phase distortion and vintage misc.-
Casio CZ series, Korg DS-8, Korg 01 series, Peavey DPM series, Roland JD-800

Digital physical modelling; Acoustic-
Korg Prophecy, Yamaha VL-1

Digital physical modelling; Analog-
Access Virus series, Clavia Nord Series, E-mu Vintage Keys, E-MuMorpheus, Ensoniq Halo, Korg MicroKorg, Korg MS-2000, Oberheim OB-12, Roland JP-8000, Roland J* series, Yamaha CS-1x, CS-2x, Yamaha CS-6x

Digital physical modelling;Established instruments (Hammond, Wurlitzer and Rhodes EP, Clavinet Clavinet)-
Clavia Nord Electro, E-mu B-3, Hammond XB-2, Korg CX-3, Voce V series

Digital sampling synth, with Analog filters-
E-mu Emulator series, Ensoniq Mirage, Korg DSS-1, Korg DSM-1, SCI Prophet 2000, SCI Prophet 3000

Digital sampling synth-
Casio SK-1, Ensoniq ASR series, Ensoniq EPS(16(+)), Fairlight CMI, Kurzweil K250, Roland S-series

Wavetable synth-
Ensoniq SD-1, Ensoniq Fizmo, Ensoniq VFX(SD), Korg Wavestation series, PPG Wave, SCI Prophet VS, Waldorf Microwave

Miscellaneous ROM sample based synths of interest-
Alesis QS series, E-mu Proteus series, Ensoniq TS series, Ensoniq SQ-1, Kawai k1 series, Kawai K4, Kawai XD-5, Korg M1, Kurzweil K1000 series, Roland/Rhodes MK-60/80, Roland D series, Roland JD series, Yamaha SY-85

Advanced workstation synths-
Ensoniq MR series, Korg Karma, Korg M3, Korg Triton series, Korg Oasys, Kurzweil K2xxx series, Roland Fantom, Yamaha Motif series

Table showing architectural class, and essential component type if analog

     When the DX7 came to town, it appeared to be all over. Yamaha getting a slightly later start into the Analog game became determined to lead the pack in this new direction and utterly abandoned their attempts to market analog designs. Roland was a major player and robust enough to where they didn't have to have to lead the industry all the time. They had established a name early on with the SH series synths which heartily competed sonically with the American machines. And that momentum kept people looking at what they would do next for many years to come. And so about the time the DX came out so did the Juno-106 which took a simple to program great sounding series and added the MIDI interface and many people just had to take their music into that realm with Roland, so they sold 70,000 units or so even in the face of a landslide towards the Yamaha products. While these products had digital oscillator sections, they still involved analog vcf/vca modules and vca chips adding a lot of expense and setup hassle to the productions. Where the new Yamaha machines were pretty much assembled and shipped.
      Even as Roland began coming out with professional digital products including the S series samplers in 1986 and the D50 in 1987, they were still doing well in analog product sales with the JX series and alpha Junos. The market hadn't dried up completely yet but Roland dominated what was left of it pretty much. But all of these even had digital oscillator control.
     Korg had followed on the heels and developed a pattern which would make them dominant in the market eventually. They let someone else do the ground breaking, and then they set forth to make it better and cheaper. The PolySix had been a huge success and instead of trying to do something bigger and better, they saw where things were going and released a synth that would probably use up some of the parts they had left over, (the Poly61 with DCO's but analog EG's and OTA based filters) and again sold quite a few though not a raving success. But it was their venture into the MIDI world and it gave them a chance to evaluate where they wanted to take things next.
     Then the Poly800 came out with a price tag and sound quality that turned it into a good success. The DSS-1 probably didn't make them much money but it did look big and bad and kept them in the spotlight with another great sounding synth and a sampler until the M1 was ready. Korg never made another synthesizer with major analog components after the DSM-1, and the DS8 which came out about the same time was again an attempt to build something similar/cheaper to what others had been doing in the digital market. The M1 was the ultimate example though, taking the best of the Kurzweil K250 in the eyes of the typical working musician and hobbyist. Leaving behind the seldom used by the typical user sampling interface, keeping the great sampled sounds in ROM, and creating an easy to use sequencer interface in a light weight yet decent feeling package (DX7 keyboard movement). Result: One of the best sellers of all time.
      Meanwhile Sequential's direction was to continue making synths with analog vco's until the Prophet VS which was a consuming project that forged the way for a new approach to synthesis, but cost them I'm sure as they only sold 3000 of them. Their Prophet 2000 sampler was somewhat popular, but Ensoniq had come out of nowhere and snagged the pole position in the econo-sampling market with the Mirage. So SCI wound up with some better products perhaps but the pricing/popularity point ARP had already gone by the way due to bad management and Moog had the SL-8 on the table but when they saw the DX7 knew there was no way they could compete. They had poured their efforts into a direction that would result in small volume sales.
     Crumar had been popular overseas and developed the first DCO synth, but they continued into the mid 80's reaping the dwindling harvest of analog hybrid sales and never really produced a significant digital intrument and eventually called it quits in '87. Siel and Elka both continued on the similar path with compromised partly analog instruments that followed trends in that area, and continued also to try to scavenge what was left of that market. Siel had began by making synths that used divider network chips with one analog VCO behind it and a full analog synth on the other side (DK600), which maintained the warmth but got rid of the expensive dedicated analog oscillators. And they began to harvest the market that was seeking a different analog sound at budget prices. Then after some variations they made some with far fewer analog components (DK70, DK80) and then some cheap digital products. They had gained enough attention to where apparently Roland thought it best for business to buy them out and shut down the factory.
     In general though those who didn't begin to design innovative digital products by 1985 ceased to do business shortly thereafter. Except for Korg, because Korg made it their business to shadow the technology and they found a great following with people who were willing to wait a couple years maybe but get something that would do the job for cheaper. So by 1987 there wasn't really an analog product that was getting any significant amount of sales and hence no advertising was devoted to these products. In the public eye that can make something very unhip, so analog synths began to be sold for very cheap prices as people tried to get money for the latest digital.
     So goes the consumer market. Anyway the first digitals all had something in common. They emulated physical processes or, actually sampled physical sounds then performed physical processes on them largely. For instance the DX7 was an "FM" synth. A natural process emulated digitally. The K150 and K5 allowed construction of harmonic arrays as we see vibrations stimulating overtones in nature. Etc. Basically doing it digitally lost some quality but the hearer could still catch the essence of a real process and they could tweak it in a way that would have been extraordinarily expensive to set up...had it not been for digital processing! However..there was a down side. With so many options and so many WRONG (in terms of the way things really interact in nature) ways you could set things up for a sound, it is easy to get lost making utterly silly sounds with these units. This inspired me to write the K5 'macro' software which allowed you to construct presets that were useful and call them up as needed so as to be able to construct a 'skeleton patch' which one could then go in and tweak to perfection. Rather than getting distracted and totally losing the idea you had as you explore all the absurd possibilities. (Though that's still fun sometimes and you do stumble onto something interesting occasionally that way...)
     Down along the path software people began to put processes more and more distanced from nature at the fingertips of the synth programmer. While it might SEEM on the surface that having a synth that can do arbitrarily bizarre things is good, many really learned quite another lesson. Perhaps a lesson analogous to what old Solomon spoke of in Ecclesiastes. He tried everything. But it kind of left him..empty! A 'chasing after the wind' and that sort of thing.
     Human beings need meaning. Connectedness. Their souls long to be in touch with something firm. Not necessarily predictable to them. But something that rather..grows with them. A great musician is like this with his/her audience. Awesome live shows aren't just a pre-planned thing that starts at time "A" and shuts off with "thank you and goodnight" at point "B". Rather awesome live shows are where the musicians are in touch with the audience and they convey something together. Something that causes each person to grow together somehow.
     Even my beloved K5m...I find sounds that are way bizarre and unreachable by other synths, but they leave me flat and cold because the processes are completely distanced from nature. They are rather arbitrary and in that way they don't connect. A sound that connects is one that has surprising qualities that lend themself to the song they are being used in (or often, inspire I find. Sometimes in creating a sound a song will emerge just from playing the sound the first time) and work together with it somehow to make the concepts all the more real to the listener.
     A friend of mine, Paul Rose, let me listen to an old 80's group called 'Negativelyland'. The first cut is a farsical message to radio station managers, explaining how they've developed this new technology which will produce a 'hit song' that is ready for release in the current market. Then they play the 'designer song' which amounts to a bunch of crazy samples of cartoon noises and annoying music hewn together with a guy finally yelling "just a minute" over and over and "I can't hear a thing" as they flow into the 'is there any escape, from noise" theme. Very funny piece.
     But also quite relevant in terms of the direction things had taken in 1987 when that was released. Many great digital instruments have been made; most of them affording us the ability to carry nice sounding piano's around without a moving crew and the like. However...sometimes too much creative headroom...into the space of being arbitrary ....can actually be a distraction to productive creativity! I know many musicians who just spend too much time fiddling and not enough actually creating music that anyone wants to listen too. There are so many sounds available for download. But where does a person stop and actually learn to play an instrument well?
     In the wake of all this, many people began to remember...something real. Analog circuitry. Subtle deep intricasies that lend themselves to making...MUSIC! Well music that lends itself to communication. Hearing natural processes unfold, rather than hearing a software engineer's idea of what sounds like it could be a natural process if like wormholes were real and the whole studio got caught in one. :-) Real..bonafide..natural processes. Like any other musical instrument that was created prior to the idea that we could write software that would be able to let us design our own instruments in an arbitrary fashion. And up many of the prices started to go again. There are still some little known gems out there that can be found at a super bargain price. But don't expect to find a Matrix 12, CS-80, Synthex, Chroma, Minimoog, Prophet 5/10 or Jupiter 8 for a few hundred dollars anywhere anytime soon again. :-)
     It's interesting to think about..creation. And how the best things come when we explore it and work within it's boundaries instead of just arbitrarily saying "hmm wonder what would happen if I totally twisted that aspect of nature?" There's nothing like the real thing. Never was, never will be. -Bob

The Synth Poll!

(Note: The number in parenthesis before a synth indicates the number who voted for it)

1) Best Analog synth (barring all thoughts of not having roadies to haul it, techs to keep it running, etc.)
    (2)Yamaha CS-80, Jupiter-8, Fenix, ARP 2600, Alesis Andromeda A6

2) Best Monophonic analog ("" "" )
    (3)MiniMoog, MiniMoog Voyager, EMS VCS3, Sequential Pro-One

3) Best practical poly analog
    Sequential Prophet 5 ( Rev. 3.3 w/ MIDI ), Roland Jupiter-8, Roland Jupiter-6, (3)Alesis Andromeda A6

4) Best practical mono or duo analog
    Sequential Pro One, (2)MiniMoog voyager, Roland SH-101, MultiMoog

5) Best full polyphonic
    (3)Korg PS-3200/3300

6) Best practical full polyphonic
    Korg PE-2000 Polyphonic Ensemble Orchestra, Korg PS-3200, Korg Lambda

7) Best paraphonic
    Roland 505, Crumar Trilogy (hey..it's semi-paraphonic with 6 shared filter/eg's) or Korg Delta

8) Best preset mono
    (2)Korg Sigma, Roland SH-1000

9) Best bang/buck monophonic
    Moog Prodigy, Sequential Pro-One, Moog Voyager, Waldorf Pulse, Yamaha CS-20M

10) Best bang/buck polyphonic
    Sequential Prophet VS, Sequential Prophet 600, (2)Alesis Andromeda A6, Akai AX80

11) Best bang/buck full polyphonic
    ARP/Solina String Ensemble (Technically partially paraphonic with one filter but poly decay eg.), Korg Lambda

12) Best bang/buck paraphonic
    is there any? (ha...ha. Only answer others gave) I'd say the Korg Delta! Or possibly Poly 800.

13) Best classic modular synthesizer
    Roland System 700

14) Best currently available modular synthesizer
    Serge Modular

15) Best bang/buck modular synthesizer
    Synthesizers.com

Honorary Mentions: Some people didn't apparently understand some of the questions. So I thought it good to mention that the Rhodes chroma did get nominated as best 'full polyphony' though it's max 16 voice poly, and also Alesis Andromeda in that category. Roland VP330 got a vote for best paraphonic. It's a vocoder and may have some paraphonic aspects. I'm not sure. That question was more aimed at the ARP omni and that type of synth which has paraphonic sharing of the filter but is full poly in terms of notes via divide down osc. Also Moog Voyager got an entry for best preset mono. However it's a programmable oriented mono not a preset oriented. This term usually refers to things like Sigma which have more preset aspects than parameters. Though it's close on sigma :-).



THanks to Steven Parsick, Mike Kent, 'jk', Guido, Alex Prescott, and...me.

Keyboards and how they interface to synthesizer circuitry -by Bob Weigel

     There are two primary types of keyboard circuit employed in synthesizers. Well, not counting those where each note is wired to an individual keying circuit. This is common in electronic organs where sometimes the 'circuit' is simply a switch that connects some tone or mixture of tones to a mixing buss. It is also used in fully polyphonic/paraphonic synthesizers though. Each note in those cases, is often wired to some diode/resistor/capacitor circuitry that allows for each note to have a discrete attack and or release time. Well the time is usually global but I mean the timing circuit starts for each note when it's engaged. Machines like the Korg Lambda have complete independence in both attack and sustain while many others compromise and leave off one or the other so that a decay or attack is interrupted when another key is struck.

Meanwhile Monophonic synthesizers like the minimoog use a resistor ladder. If you put precision resistors in series and put a precision voltage reference across them, then at each joint between resistors a voltage will reside that is of course proportional to the location in the chain. in cases where there are an even number of resistors for instance, if you have a 5V source across the chain, then half way between will be 2.5V within the precision afforded by the resistors.
      A control voltage for a VCO may therefore be achieved in this sort of way. When a key is pressed then a contact shorts one of the connections between resistances to the control voltage buss and the change is detected and a sample and hold cell is opened to read the voltage. The voltage can then be stored when the key is released so that the oscillator does not drift in pitch during a release envelope for example.
     If multiple keys are held, then in this sort of arrangement the pitch will vary strangely. For example what happens if you hold the second highest and lowest notes? This would create a wire that touches between the first and last resistance and hence the contacted buss would be at about half the reference voltage! ie. it would play a note from the middle of the keyboard.
     To overcome this an op amp bias supply is used. In this circuit the whole ladder is placed in the feedback loop of the amplifier. When a key is pressed it taps the voltage ratio between the ends of course and that goes to the input of a buffer amp which then feeds the sample and hold circuit. But when multiple keys are pressed the reduction in impedence results in a rapid adjustment of the output of the amplifier to correct it so that the highest or lowest note being hit is represented in the CV. The easiest circuit to study I think is the moog satellite.

      Polyphonic synthesizers demand a different method since there must be multiple keys whose positions are recorded simultaneously. For this task digital methods are much easier. The Yamaha SK20 diagram shows a fairly easy to see example of a key scan circuit. Here a processor has lines wired to each octave of notes. That is to say all the switches have a common let in that octave. Octave 3 for instance. The other side of each switch in that octave goes to the anode of a diode. And the cathode of each diode ties to another line that is common to all of it's note value. (Eg. "Dflat"). And these lines go to another pin on the processor.
     In this way a processor can be programmed to continuously be cycling through a routine of raising the voltage on one of the octaves at a time. And as it holds that line high it then checks the status of each of the note value lines. If it reads that one is high then it now knows which note of which octave is being held at that moment in time. Were it not for the diodes of course, then the situation could occur where you are holding, say, an F# in the 5th octave. But not the C#. You are holding an F# also in the 2nd octave and also a C# there. Without the diodes, the F# bus going high would feed back through the F# of 2nd octaves' key switch to the C#'s closed switch and would raise also the C# buss. THe processor upon scanning would discover the high C# buss and would assume that the 5th octave's C# was being held. Or it would have no way to tell that it wasn't being held at that point I should say. Hence the diodes.
     Once the CPU has captured this information it is then able to store it and circuitry is able to act on the information. Since processors usually run 100's of thousands or millions of instructions per second, it is quite impossible to sense any delay in the sensing process. That summarizes the typical key scanning method employed in most digital and analogy polysynths.





Memory implementation in analog synths. -by Bob Weigel

(Note: You may prefer to watch the video on this topic on my sounddoctorin youtube channel!)
     In units with panel controls, Variable resistors give a span of voltages as they are turned, and this voltage is attached to the input of an analog multiplexer. (this is a chip that has often 8, 10, or 16 lines; one of which at a time can be addressed to attach to a common line. So obviously the 8 channel mux has 3 address lines since there are 8 possibile combinations of address line highs and lows.)
     Ok so the CPU walks through the address possibilities AND further "selects" are used often to decide which chip is going to be accessed out of an array of them if we need more than 8 knobs to be read for instance. So anyway it walks through all the knobs and as it does it also calls forth the data previously stored in association with that knob from RAM. For machines which allow knob editing of previously stored data, there is a 'patch buffer' which is volatile memory often that stores a temporary copy of the data being worked on. Anyway, this data is latched for a DAC to convert it to an analog voltage. This voltage is fed to the pin of a comparator and the other leg of the comparator reads the knob's voltage that is currently being read. The output is always high or low on the comparator and so say they really are the same data..ie...nothing has changed in the voltage being fed from the knob's potentiometer. The CPU begins stepping the RAM data up until the comparator flops the other way! In the case where the data was supposed to be the same...this should be within ....whatever the resolution uncertainty is decided to be for the conversion process. And the software that runs the cpu is written such that if the comparator flops the other way within x number of increments, the data is considered the same and no change is made. The old data is refetched and written back, lest we walk around and create a perceived movement that wasn't actually there I suppose.
     And if a knob is actually moved (or you get a dirty/broken pot and it thinks it has moved...) then the cpu recognizes that the resolution limit has been exceeded and it assumes movement has occurred and allows the new data to remain stored in the patch buffer until a write command is issued in which case it will overwrite the old SRAM data.
     MEANWHILE..how does this information actually get to the analog circuitry? Usually the DAC output. Thus when you move the knob it takes the comparator acting as an ADC in conjunction with the CPU in order to bump the data up, and modify the DAC output to correlate with what the knobs are saying. This information simultaneously drives the comparator input AND is fed to another series of 4051 common inputs. As a chip is selected and the appropriate address is fed, the appropriate chip opens it's 'gate' and allows the analog voltage to flow onto a small sample and hold cell's capacitor. Then when the gate closes as the next function is being dealt with, the JFET or MOSFET input op amp buffers that voltage so that the capacitor is not quickly drained. And it's that output voltage of the op amp which actually drives the analog circuitry that is performing the analog synthesis function.