Wednesday, January 30, 2008

Show us your rear!

The rear of your rack, that is.  Is it neat and orderly, or does it resemble Paris Hilton on a bad hair day?  Here's mine -- you be the judge: Modular Form Factors Table

This handy-dandy table, from, lists every modular series currently in production plus a number of vintage brands, with the physical dimensions of the modules, the type of patch cord jacks used, and the required power supplies. This is great information for anyone planning to build a Frankensynth modular, as I have with the Discombobulator. Note that this isn't necessarily all of the information you will need; there are still issues of required case depth and mounting hole patterns to consider. (For instance, and MOTM modules are close to the same height, but they don't use the same mounting hole patterns.)

Tuesday, January 29, 2008

SMPTE time code

This is an expanded version of a post that I originally posted to the Help! forum of VSE on 17 January 2008.

What SMPTE basically does is encode a time code into an audio signal, kind of like the way a modem encodes data into an audio signal that you can send down a phone line. The idea is that you can record a SMPTE time code signal on one audio track of a multi-track tape (this is usually called "stripe-ing" the tape), and then when the tape is played back, the playback of the time code can be used to synchronize other things (such as sequencers) to the tape. This works because if the tape slows down, say, then the time code slows down too. Because SMPTE (the acronym stands for "Society of Motion Picture and Television Engineers") was originally intended to synchronize video sources, it counts time in terms of hours, minutes, seconds, and frames from an arbitrary zero-time starting point.

Because SMPTE is used to sync audio to video and film, there are a number of different standards for the number of frames that constitutes one second, according to the visual medium being used:
  • 24 fps: Film
  • 25 fps: PAL video, used in Europe
  • 30 fps: Black-and-white NTSC video, USA and Japan
  • 30-drop: Color NTSC video, USA and Japan. This one is an oddball that compensates for the fact that NTSC color video is not exactly 30 fps; it's slightly slower. Instead of dividing the time code second into a non-integer number of frames, which would be really awkward, it has the frame counter skip two counts at the beginning of certain minutes, in a repeating pattern, so that the time code stays within a few milliseconds of the video. If you tried to sync audio to NTSC color video using 30 fps time code without the drop frames, at the end of an hour, the audio would be about four seconds ahead of the video.

So what does the electronic musician use SMPTE time code for, and how is it used? SMPTE time code is used in electronic music primarily to synchronize a sequencer (or some hardware containing a sequencer, such as a drum machine) to a taped audio track. Some seqeuncers have the ability to generate and read SMPTE time code directly. Some MIDI interfaces, such as the MOTU MIDI Time Piece / MIDI Express can generate a SMPTE signal to stripe a tape, and then on playback, read the SMPTE and translate it to MIDI Time Code (MTC). Consider a setup with tape, a SMPTE-reading MIDI interface, and a drum machine being driven by MIDI. At the start of the production, the SMPTE generator in the MIDI interface is used to "stripe" a time code on one track of the multitrack tape. This starts from some arbitrary starting point on the tape, which the SMPTE generator encodes as time zero, with time counting up from there. Audio tracks are then laid down on the tape, at a tempo regulated by a click track generated by a drum machine playing at a set beats per minute (BPM). The audio tracks may start at some arbitrary time past time zero on the tape.

After the audio tracks are recorded, the simple click pattern programmed in the drum machine is replaced by a full-up drum sequence. It is then needed to play back the multitrack tape in sync with the drum machine, so the result can be mixed down. The track of the multitrack tape which contains the SMPTE code is routed to the SMPTE reader on the MIDI interface. The tape is positioned at the start of the audio and the SMPTE time at that point in the tape is read. This is then programmed as an offset into either the drum machine's sequencer, if it has the ability to do so, or perhaps into the MIDI interface. When the tape is played back, this offset is subtracted from the current SMPTE time to determine where the drum machine should begin. Playback is started, and the MIDI interface reads the SMPTE time code and translates it to MIDI time code which is routed to the drum machine. The drum machine then plays back in sync with the tape. Further, unlike simple protocols such as DIN sync or MIDI Clock, the SMPTE/MTC combination allows the tape to be started at any point in the song and the drum machine will start at that same point -- no hand cueing is necessary, since the SMPTE code indicates actual time and not just clock ticks.

To summarize: For electronic music production: 1. If you aren't syncing sequencers to tape, or syncing two tape machines, or syncing audio to video, you don't need SMPTE. 2. If you are syncing to tape, but video isn't involved, you can use whatever frame rate is convenient. Most people who do this use either 25 or 30 fps because when you do time calculations, it makes the math easier.

Further reading on SMPTE time code:

Monday, January 28, 2008

Future of large-format modulars?

I've noticed that over the past two years, most of the action in new and different modules for modular synthesizers has been in the small formats, particularly Eurorack. In addition to the ever-growing Doepfer line, the past two years have seen the emergence of Plan B, Livewire, and Harvestman, plus the beginnings of the Cwejman modular line. Analogue Systems continues to grow its impressive product line too.

On the other hand, in the most widely adopted large formats, there isn't nearly as much going on. has focused most of its development effort for the past couple of years on re-creating the Moog 960 sequencer modules -- a worthwhile effort, as far as it goes, but not exactly new. Cynthia has introduced two modules, but is concentrating mostly on offering its existing line in multiple formats, and they have dropped several older modules from their line (was I the only person who bought the StereOSpace?). Synth Tech had big plans a couple of years ago, but the business suffered a setback with the incapacitation of one of the principals (plus the tragic death of Stooge Panels co-founder Larry Hendry). They introduced the MOTM-480 and 485 filters, the very under-appreciated 510 WaveWarper, and the 650 MIDI interface. But a number of other planned modules, including a cloud generator and a fixed filter bank, had to be put on the shelf.

It's not all gloom and doom for large format manufacturers. Modcan continues to grow its line, particularly the MOTM-compatible B-series. Bridechamber's offerings also continue to grow (mostly in the MOTM format), and include a number of kits. However, there is nothing like, say, Harvestman's digital mangling modules being offered by any large-format manufacturer.

So is small-format the future of modulars? Are those of us with fat fingers facing a future of twiddling tiny knobs and breaking off teensy weensy 3.5mm jacks?

Sunday, January 27, 2008

My latest acquisition

My latest Ebay acquisition -- The E-mu Morpheus:

 I've been on the lookout for one of these guys for a while.  Unlike most of E-mu's Proteus-based ROMpler modules, the Morpheus doesn't usually turn up on the used market very much.  I've been watching the occasional one appear on Ebay for a couple of years now, and they usually sold for around $400, which is about double what most of this era of E-mu modules goes for.  However, recently several turned up on Ebay at once, and I was able to win this one at around $200.  

Going back to the late '80s, when E-mu first started selling the Proteus modules, one of the big complaints about then was that they had no filters.  When E-mu finally decided to rectify that, they didn't just implement software versions of the standard 2-pole and 4-pole filter types commonly found in analog synths.  Instead of trying to re-create the analog domain, they took advantage of the software environment to create a huge variety of formant filters, comb filters, and some arbitrary filter equations probably never seen before (or since) in a musical instrument.  Then, they gave each filter 2 or 3 variable parameters which can be tied to either the note value (which key is being played), velocity, or various MIDI Controllers.  For example, one one filter type, the "morph" parameter controls the resonance; on another, it controls the number of notches in a comb curve.  

Another feature that I was surprised to find, because I've never seen it commented on before and the older Proteus modules don't have it, is a very flexible and powerful universal event generator.  It has eight steps, and for each step you can independently set time, slope, and shape (there are a huge number of linear, exponential, circular, and arbitrary shape choices).  You can also set certain steps to be skipped or repeated based on certain events happening or not happening.  

Like most of the Proteus-based modules, it has the notorious "peephole" user interface.  You press a button to select a category of parameters to edit, press other buttons to move the cursor to a parameter name field.  You turn the rotary encoder until the parameter you want appears.  Then you press the cursor buttons to move the cursor to the parameter value, and turn the rotary encoder to change the value.  I already have a Metro sequencer file with a bunch of virtual faders that are set up to send Proteus sysex sequences; I can edit most of the parameters on my Proteus/2 with it.  Hopefully it won't be too much trouble to alter the sysex templates to edit the Morpheus parameters.  There is a patch editor specifically for the Morpheus, called MorphEdit, but it's Windows only, and I'm running OSX.  

And: the build quality of the Morpheus seems to be much better then the Proteus/2.  The Morpheus' case is metal, unlike the plastic cases of the earlier Proteus modules.  And the buttons and the rotary encoder feel better then the rather flimsy ones on the Proteus/2.  It didn't come with a manual, but you can download manuals for nearly all E-mu products on their support page.  

Monday, January 21, 2008

NAMM post mortem

So besides the Solaris, the most interesting I saw in the NAMM videos was the Arturia Origin. Basically, it's a sort of soft modular system that is loaded up with all of the classic-analog emulations that Arturia is known for, such as Minimoog-V and CS-80V, along with the ability to cross-patch them in any way desired. VAs aren't really my cup of tea, but if I were into it, I would definitely be looking at the Origin. Other bits that jumped out at me: G-Force's M-Tron Pro, which looks like it is poised to go beyond just being an amazingly accurate Mellotron emulation (even though that's an impressive accomplishment in itself), with the addition of Opitgan and Birotron sound banks. Dave Smith Instruments showed a rackmount/tabletop version of the Prophet 08, and Access had their bite-size version of the Virus TI. For those who can't stand even the slightest hint of digital circuitry in their synths, there was the appropriately-named Moog Voyager Old School. Akai brought a newly expanded version of their very good MPD drum pad controllers, the MPD-32, with more faders, dedicated DAW controls, and a neat tempo generator that can create a master MIDI Clock from a tap tempo.

There don't seem to have been a lot of really innovative or out-there products this year. The Solaris was probably the most advanced synth present, but this wasn't the first time it has been exhibited (it was at Musikmesse Frankfort last year). An outfit called Sonivox announced a software package called Anatomy. I've read the description twice now and I'm still not quite sure what it does; it's a package of vocal samples with processing options, or a physical model of the human voice tract, or possibly both. In another example of the recent throw-objects-on-a-table-and-interpret-it-as-a-drum-pattern school of synthesis, an outfit called Percussia exhibited a product called Audio Cubes. They sense each others' presence, where they are in relation to each other, and which sides are facing which way. They connect to a computer using USB, and with an included appliction, they can be induced to either play loops, or send MIDI data to external synths and applications.

Sunday, January 20, 2008

Solaris demo

I've got one of these puppies on order. See the demo vid here, from SonicState. If you're interested, they have a couple of money-saving deals on pre-orders. The John Bowen Synth Designs site is here, and it includes a forum where users can ask questions and interact with Bowen himself. He's been really good about taking user suggestions concerning the design of the Solaris.

Monday, January 14, 2008

Solar Flare, Parts 4 and 5 up on Web site

All of Solar Flare has now been posted here, and the text has been updated.  I think I'm done with five-part, twenty-five minute production extravaganzas for a while.  More Statescapes!

Solar Flare, Part 3 up on Web site

The third part of Solar Flare is here. I haven't completed the writeup yet, but the music file itself is now linked. It's rather different from the first two parts; it's in a strict 9/8 tempo and it's pretty atonal. I used a microtone scaling on the JD-800, lots of pitch shifting, a Csound-generated bass part, and even the Kramer aluminum-neck headless bass makes an appearance.

Wednesday, January 9, 2008

On the Workbench: Juno-106, part 2

Calibrated the 106 last night.  First, some photos from the end of the repair job.
The module board was too wide to fit on the Panavise the conventional way.  I had to stand it on its end:

The new 80017A ready to go.  Note that the lot number is actually older than the one it is replacing!

The new part installed and ready to rock:

Next up: calibration.  The last time I calibrated the 106 was four years ago, and I was curious to see how far off things were.  I already knew the VCF on voice 4 was a bit sharp, and when I played the synth after powering it back up, the one on voice 5 was about a whole tone flat -- not surprising since it had just been replaced.  There are 10 steps in the calibration procedure (from Daredevil's page; there are two files.  Scroll to down near the bottom.)   The first is to check the power supply voltages and adjust as needed.  The procedure wants the voltages accurate to within 0.01V.  That's just within the precision of my DMM.  I measured the -15 supply at 15.06, so that was very close.  Careful tweaking on the trim pot got it to -15 on the nose.  Probing the power supply board:

The next step is adjusting the DCO control voltage offset.  In the test mode, you press the MIDI CH button and it is supposed to go to exactly 0V.  I was a bit surprised to find that mine was dead on (sorry about the photo orientation):

Step 3, VCA bias.  It was within range.  Step 4, VCA offset.  This adjustment minimizes control voltage feedthrough, which causes thumps or pops in the audio output when the control voltage changes abruptly.  This is what control voltage feedthrough looks like on the scope:

This was from voice 5.  Voice 2 had a bit of offset, not this bad.  The other four voices were already as flat as I could make them.
The next steps get into the VCF adjustments, and are the trickiest part of the procedure.  Step 5 calibrates the VCA resonance for each voice.  A test mode puts the VCA sets the resonance high enough to cause self-oscillation, which generates a sine wave.  Which has to be visually trimmed to 4.8V peak-peak on the scope.  (I don't have one of those fancy scopes that can measure it for you.)  With the reticle illumination cranked way up, this is what I was looking at:

One thing that helped was using the delayed sweep on the scope to position the peaks exactly on the reticle line intersections (and at the left edge, as you see above), which made the position of the peaks relative to the reticle easier to see.  Voices 4 and 5 were a bit high; the others were close enough not to mess with. 
Step 6 adjusts the VCA gain, using the VCF-generated sine wave.  All voices were on spec except voice 6 which was a bit high.  
Step 7 adjusted the VCF cutoff frequences.  You're supposed to use a frequency counter to do this.  But my scope doesn't have a frequency counter; the DMM does but it's not accurate enough.  And anyway, I don't like doing it the way that the procedure recommends -- they want you to tune all of the VCFs a semitone flat for some reason.  So I do it by ear.  In the test mode, you can still use most of the patch editing controls.  So I checked the VCF self-oscillation against the DCO by turning the pulse wave on and off, and listening for a pitch change.  I tweaked the PWM control to get a similar volume to the VCF self-oscillation.  Holding down the middle C, I toggled the pulse wave on and off and listened.  
Much to my surprise, the voice 4 VCF (which I had thought was sharp) was dead on; all the others were flat.  Most of them were flat about a quarter tone.  The trim pots have a large range and you need a delicate touch to bring them those last few cents.  Voice 5 of course required a big change.  I recall that the last time I calibrated the 106, the VCF on voice 5 was way sharp and I had to crank it a lot to bring it in.  I seem to recall then when the 800017A on voice 6 failed in 1991, it was sharp just before it failed.  I'm starting to wonder if a VCF that has drifted sharp is the advance warning of an 800017A about to fail.
Step 8 adjusts the VCF scaling.  The scaling interacts with the cutoff frequency calibration, and the last time I calibrated the 106, I was caught in a loop between these two things for a while.  But this time, the scaling needed very little tweaking, mercifully.  I think I just touched voice 3, not enough to effect the cutoff frequency tuning.  
Step 9 adjusts the noise level.  I was surprised to find that it was waaaaay hot, 6V on the "average peak to peak" method shown by the procedure, as opposed to the spec of 4V.  Last week, when I was working on Solar Flare, I recall thinking that the noise on the 106 was rather prominent in a patch that I was using.  Maybe I should go back and mix that again to see how it sounds.  
Step 10 calibrates the PWM adjustment in the DCO.  You trim the circuit to get a 50% pulse, and then again to get a 95% pulse.  This was on spec and I didn't have to touch it.  A photo of the scope display:

Note the bit of ringing on the leading edges, and the slight downward (towards zero) slope on the tops of the pulses.  The pulse wave on my 106 has always looked like this, and it's the same on every voice.  I've always wondered if this contributed some to the character of the pulse wave on this synth.  But I don't know if other 106es exhibit this behavior.
The last step is supposed to adjust a DC bias in the chorus circuit, to minimize clipping in the chorus.  It's kind of a pain because you have to connect a signal generator to a test point on the audio board, scope the synth's output, and then adjust some pots on the jack board that are kind of hard to get to unless you put the synth right at the edge of the workbench where you can open the panel up all the way.  (As it was, I put a block underneath the back of the synth to allow the panel to open as much as shown in the photos.)
It works as good as new now, and the sound is still that great 106 sound.  One more photo, of the completed and calibrated synth just before I buttoned it up:

I'm going to put up an expanded version of this post on the Web page eventually.  It will contain the complete calibration procedure with my notes, photos, and illustrations, along with some troubleshooting tips I've compiled in my years with this synth.

Tuesday, January 8, 2008

The patient survives...

The 106 is up and running again. For some reason, I had a devil of a time getting all of the solder out of the holes after the old 800017A was removed. But the new one is in and all six voices are working. I didn't have time to calibrate it last night.

More info and pics tonight, if all goes well.

Sunday, January 6, 2008

On the Workbench -- Juno-106

My Juno-106 has had a dead voice since last summer.  And yes, it's the infamous 800017A IC.  The usual symptoms of a failed 800017A are a voice that is crackly, intermittent, or sounds like it has a bad connection somewhere.  Eventually it will go almost totally silent, with perhaps some cracking and very intermittent periods of good operation if you turn the VCF cutoff frequency and resonance all the way up.  Using the test mode (from Daredevil's Jupiter and Juno Page, a very good resource for calibration procedures, schematics, and factory patches), I determined that the dead voice was voice 5 (which I kind of thought already, but the test procedure confirmed it).  

So off it went to the workbench:
You access the interior of the 106 by removing the two screws recessed inside the handgrips in each of the end blocks.  Then, the panel opens up as you see here.  The long green board on the left is the module board, which is where all of the sound generation circuitry is.  (The smaller green board in the center is the CPU board, and the yellow board on the right is the power supply.)  There are five or six connectors to unplug, and six brass screws to unscrew, and the board comes out.  
The board is clearly marked as to which of the single-row ICs go with which voices, but I checked with the schematic to make sure.  Each voice has its own 800017A, which contains most of the VCF and VCA circuitry for that voice.  In between each pair of 800017As is another IC that provides the DCO for two voices.  The DCO ICs rarely fail.  IC5 is the 800017A for voice 5.  Most of the instructions I've seen for replacing these recommend cutting the pins from the failed IC in order to remove it, and then using a soldering iron to extract the remains of the pins.  This is to prevent any possibility of lifting traces off of the 25-year-old circuit board.  However, space was too tight for me to get my cutters in.  I solved the problem by just worrying the IC back and forth until metal fatigue snapped all of the pins.  Then, I used a soldering iron to heat each pin stub, pulling it out with the cutters, and using a solder bulb to clear the remaining solder.  The result:

You can see the space where IC5 was.  

There is some controversy as to whether certain lots of the 80017A are more likely to fail than others.  The Wikipedia entry for the 106 claims that lot #41 units are most likely to fail, but at least one poster at Matrixsynth has disputed that, saying that all lots are equally likely to fail.  The ones in mine are: voices 1-3 are lot 43B, voices 4-5 (including the dead one) are lot 42A, and voice 6 (which was replaced in 1991) is lot 61A.

To be continued...

Saturday, January 5, 2008

Solar Flare, Part 2 up on Web site

Solar Flare, part 2 is here.  It's longer and a lot more involved than part 1.

Thursday, January 3, 2008

Solar Flare, Part 1 up on Web site

Finally, I get some new music posted!  As some of you know, my wife and I went through a nearly three-year-long saga of house building.  (It actually isn't over yet, but we are living in the house and things are nearing normal, finally.)  Back before we began that odyssey, I started a piece of music titled Solar Flare, with the intent of musically representing a solar cycle.  (Pretentious much?  Who, me?)  The piece got shelved when the house wars began, and I was only able to get back to it last spring.  Well, I have finally nearly finished it, and I've put up the first part here.  Over the next couple of weeks, I should get all five parts up.  They are:
  1. Cycle 24 -- represents the solar cycle that is due to begin in March 2008.  A rather quiet bit that opens the piece.
  2. Prominence -- A solar prominence is a loop of the photosphere material that is made to rise from the surface as it follows the Sun's changing magnetic flux lines.  Prominences are associated with flares and sunspots.  Musically, this part is a bit of a nod to Jarre, with a pulsing bass line, pads, and lots of noises and things weaving in and out.
  3. Magnetic Revolutions -- The Sun's magnetic field is in constant turmoil -- in fact, it totally inverts itself (the magnetic North and South poles swap) every solar cycle.  This part will be rhythmically, tonally, and scale-wise in oppressive turmoil.
  4. Storm -- The solar flare, and its effects on Earth: fried satellites, power failures, and Northern and Southern Lights.  An improv piece using the EML 101.  This was actually the first part of Solar Flare to be completed (it's been on the shelf for a while).
  5. Cycle 25 -- The following solar cycle, starting in 2020.  How will it be different or similar to Cycle 24?  This part is a re-statement of Part 1, with variations.
I hope you find it interesting.

Does The System survive the XM/Sirius merger?

XM's channel 82, The System, is probaby the single largest outlet for trance and related forms of electronica (in terms of the number of potential listeners it reaches) in North America. However, I see Internet rumors that the channel won't make the cut after the merger with Sirius. And it is my understanding (I'm not a Sirius subscriber) that Sirius has no equivalent channel, so it's not just a matter of eliminating a redundant channel. The rumor seems plausible, because The System is one of XM's few music channels that is not produced in-house; they buy it from Worldspace. The combined company will doubtless be looking to cut costs, and buying out-of-house music programming looks like a big target.

Tuesday, January 1, 2008

Overlooked Synth Classic: Anthony Phillips' 1984

Anthony Phillips is best known as a guitarist, and a mostly-acoustic guitarist at that.  (He was a founding member of Genesis, preceding Steve Hackett as the band's lead guitarist.)  But in 1981, he produced an album unlike anything he has done before or since: 1984.  This is an album of unabashed synth music, with only a few smatterings of guitar here and there.  Other than that and some percussion, everything here is synth.

The album came as a total surprise to Phillips' fans at the time.  A brief opening theme and an equally brief closing theme serve as bookends to two long compositions that took up nearly all of their respective album sides on the original vinyl release.  Bearing little resemblance to the Orwell classic novel, the album opens with an upbeat "Prelude '84" containing a pulsing bass line, fast lead synth runs, jangly piano-ish chords, and an electric guitar counterpoint.  That leads into "1984 Part 1" which begins at a slightly slower tempo, but with huge washes of chords with a massive, sliding bass line, segueing into a steel-drum patch playing a poppy sequence of chords and melodies.  The piece continues in a most amazing fashion; there are around a dozen different themes in the song, but it segues from one to the next so effortlessly that the listener hardly notices the transitions.  There are fast bits, slower bits, loud bits, quiet bits, all blending together into a seamless sequence of melodies.  The song, and the album side, conclude with a big wash of pad chords leading to a cliffhanger ending.  (Back in the days of vinyl, this was the way to do it; the ending set up the listener to anticipate what would come next, during the couple of minutes that it took to get up off the couch and flip the disc over.)

"1984 Part 2" begins with a reprise of the first part's opening theme, but quickly goes in a different direction, building up tension with a series of leads played over an ominous bass and percussion line.  But this leads to a set of quick theme statements and changes, which eventually wind down to what sounds like the end of the piece -- but after a short pause, a flute-patch melody leads to the climatic buildup.  Some sort of vocoded vocal sings the title "Nineteen eighty four" several times (the only vocals on the album), there is a brief tempo diversion, and then the piece builds to an abrupt end.  The slow, stately "Anthem 1984" concludes the album.

As noted above, the mostly uptempo music appears to have little to do with the Orwell novel; the many style, key, and tempo changes through the two extended pieces cause the listener to eagerly anticipate the next bit of the music -- in other words, the future, unlike Orwell's Winston Smith.  In fact, it almost seems that Phillips rejected Orwell's dystopian vision of the future, and made this album as a refutation of the novel.  Whatever the reason, this is one neat bit of synth music.  Some of the sounds are a bit dated now, but mostly it has held up well.  The synths used appear to be nearly all analog, and the beatbox drums fall into the so-retro-it's-cool-again category.  (It helps that they are complemented by percussion parts contributed by Richard Scott and Morris Pert.)  The origins of the compositions are a bit murky -- an Analog Heaven rumor from a few years ago had it that Scott (who would later be Phillips' co-conspirator in the group Invisible Men) actually wrote most of the music.  There may be some truth to that, given that the album is absolutely atypical of Phillips' output.  In fact, at the time of the original release, it sold poorly; Phillips' usual fans didn't take to it, and people looking for synth music didn't think to look under Phillips' name in the record store.  Some time after the original release, a CD was released containing all of the tracks of the vinyl album plus some more.  A brief Amazon survey shows that people who have copies of the CD for sale want $40-50 for it now, so someone certainly recognizes it as worthwhile.  If you get a chance, check it out.