Controlling a synthesizer WITH YOUR MIND!!
Sep 3, 2010 Gear
Check out some cool videos of a DIY mind-operated voltage control system driving some synths, created and played for you by the lead guy from Apples in Stereo, here.
Irregular Timing With STG Soundlabs Voltage Mini-Store
In my Synthesizers.com modular system, I use STG Soundlabs’ time modules for my sequencing. I’m pretty sure that I’m abusing them somewhat, and I can’t lay a finger on why precisely I like them, although I think it’s mostly the flexibility. I like that I can build up a sequencing tool with exactly the functionality I want when I want it.
However, many of the big integrated sequencers have an option for “third row timing” — that is to say, you have, say, three rows of eight knobs which you would typically use to send voltages, either as three separate sets of voltages (say to play a sequence of three-note chords, or to control a pitch, an amplitude and a filter cutoff for each of eight notes in a sequence) or as a series of 24 voltages, and you can take the third row, or the last eight, and in the former mode you can have that row control the timing with which the sequencer moves, moving it forward with more or less speed depending on where that knob is set.
I had a need to do this the other day, and discovered that it’s exceedingly simple to do. In fact, my example patch here has more to it than you really even need:
Irregular Sequence Timing with STG VMS Patch
What’s happening here is very simple. You’re using the manual shift inputs on your two STG Soundlabs Voltage Mini-Stores to advance the sequence, both driven by a pulse wave coming from an oscillator. I’m using a Q106 in the diagram here, so I’d have it set to the LOW range, but you could use any voltage-controlled LFO that outputs a pulse.
The VMS shown on the left is the one that controls the timing, so you set its knobs to the speed you want that step to progress at. The higher the value of the knob, the faster the speed of the step, the shorter the sequencer waits on that step. That might be counter-intuitive for some, so you could use (a) signal processor(s) to flip that over if you wanted to. Its output gets patched into the Q106′s exponential frequency input. You could use the linear frequency — that might be more intuitive for tracking a knob, it it also alters the available range. The frequency knob on the oscillator is used to set the base tempo that you’re working with, in a sense.
The really optional thing I have going on here is that between the VMS and the Q106 I put a quantizer. I’m using the Synthesizers.com Q171 Quantizer Bank in this diagram. The reason for this is that by and large you want to choose from a set of timings rather than having the timing of each step be completely fluid. If you set two knobs to about the same value you generally want the sequencer to pause for exactly the same time on that step. I use a quantizer to do that, even though I suppose you’d need to use the aid module and restrict the available choices to get exactly musically useful fractions. It works well enough for me just putting it through raw as shown.
The pulse output of the Q106 needs to go to the shift input of both VMS modules, of course, because you want to move them both from step to step in lockstep. You could use a multiple for this (which is actually what I do) or just a Y-splitter as shown. If you have them hooked up to a shift manager, it wouldn’t hurt to also plug the step 1 trigger of one to the reset of the other to keep them in sync.
The output of the VMS shown on the right goes to control whatever you want to control — the pitch of a sequence, for example. You could send the Q106′s pulse to more than two shift managers to control several parameters at once. After the first VMS, all others would be “output” ones — used to control parameters. If you use a Q962 to string together 2-3 VMS modules into a 16-24 step sequence, you can do that, although you’d need an equal number of steps of timing control as steps of parameter control (although again you could control multiple parameters with no additional timing modules needed). And you’d need a Q962 for each set. So for 24 steps of custom-timed sequencing of three parameters, you’d wind up needing one Q172, one Q106, 2 Multiples, 12 Voltage Mini-Stores and four Q962s, which, unless you already have them, strikes me as a lot more costly than just doing it all over MIDI -> CV in some fashion. But perhaps more fun, too.
Success! Sort of…
It worked! The new soldering iron was beautiful, so you can stop being stressed about the responsibility, Andrew. :) It really made it a joy to solder.
The overall hack is a tad unstable, so I haven’t made a video of it yet or labelled it or anything. I’ll try to take some photos, though. I have some ideas as to what might be happening.
Here’s what it does at the moment that’s desired:
- Switch selects between internal and external sync modes.
- Switch selects between run/stop modes when internally synced.
- Knob selects tempo when internally synced.
- When externally synced, tempo is correctly retrieved from incoming MIDI clock.
Here’s what it does that’s less desirable:
- Sometimes it takes a long time to switch between modes — longer than I have a good explanation for. Other times it switches more quickly.
- Sometimes when you touch the knob or the switches, the whole thing kind of freaks out a bit.
- Sometimes it produces very strange output for a second or two before successfully switching between modes.
It was doing this during the testing phase when I was just using a bunch of alligator clips to hold everything together, so I had thought it was just the noise and unreliability of that. Now I’m not as sure. It almost seems like something’s shorting with the metal plate that it’s all mounted against, although I thought I’d triple-checked that that wasn’t the case. The one thing I’m wondering is if the knob, which is on the back mounted almost flat against the plate, is causing some kind of issue. I could put a washer or a nut on it behind the metal plate as a kind of spacer.
One thing that I should mention is that I kind of built this as a bit of a hybrid between permanent and temporary installation. I don’t have a screwshield or anything of that sort for the Arduino, so all connections to it are being made through these sort of push-in solid cables like you’d use when prototyping on a breadboard. My circuit, simple though it is, is actually on a mini breadboard that’s mounted to the plate. So all of those connections between the Arduino and the breadboard are not soldered in. All the connections to the knobs and switches are, though, and anything else which I realistically could. So if I can’t find some other source of the problem, that might be a next step — actually putting this on a board and soldering it all down. But those connections seem pretty solid, so I don’t think that’s it. I’m leaning toward the knob. I suppose I could use the multimeter to test if the value it sends ever goes totally wonky.
Anyway, I’ll post some pictures and videos at some point, either later to solicit input on the problems or when I get it fixed up.
Back in business! (Almost…)
Guess what arrived today!
No. No. Not that either.
Yes, my new soldering iron!
- Weller WTCPT Temperature Controlled Soldering Station
I went with Andrew Martens’ suggestion in the end, because he had personal experience with it and he’s kind of my go-to guy for advice on this stuff.
So tonight should be either awesome or completely demoralizing! Either way, I promise an update once I’ve given it a whirl.
(And maybe someday I’ll get back to making songs instead of just geeking out. 
)
)
The Great Soldering Iron Saga
Apr 8, 2010 Gear
Well, last night when I was so frustrated with my cheap soldering iron, I threw it in the trash. Well, I waited for it to cool and then threw it in the trash. My trash bin is metal and was empty and I mostly did it out of frustration.
I thought about it a lot overnight. Today I thought, “Okay, I will look at it and figure out if there’s anything I can do to improve its performance, and if I still think it’s useless, I’ll buy a new one.”
However, just like people who store important documents in their computer’s recycling bin (yes, people really do this), I left it there figuring that I just fish it out this evening.
Today was also the day that our cleaning service person comes. Helpfully, she took out the trash.
So… I guess that decides that! New soldering iron for me!
Sync Project: Not a day, really
Today’s conclusion: My soldering iron sucks. A lot. I have to go get a new one.
Sync Project: Day The Penultimate
I think I’ll only be working on this for one more full day, with any luck. Despite that knowledge, I’ve found this phase of the project to be really disheartening, in a strange way. I’ve got all the drilling done, and the controls mounted in the plate, the arduino mounted on the backplane and the breadboard glued to the inside of the module. So what’s the problem, right?
I dunno. I think it’s that this segment has been so half-assed and kludgey. I don’t have the right tools or components to do this sort of work well. The result looks okay, but still. Also, to get it done I had to disconnect pretty much all the cables, and in the process of trying to get it to work without doing so, a bunch got pulled out again. I’m not entirely sure what’s missing and what’s in there now, and I have these pictures of blowing everything up in the 11th hour. And the third or fourth time you re-assemble a project from scratch, well… it’s not super fun anymore.
Furthermore, testing was… well, it all worked, sort of, but it wasn’t a stellar runaway success, per se. I’m worried that when all is said and built, that’s as good as it’s going to get — unreliable and prone to dramatic failure.
I suppose only time will tell, and I shouldn’t get too pessimistic. We’ll see whether I can get it done tomorrow, when I have the evening completely free. I’ll have to overcome my general trepidation about the soldering iron — although I’m using a breadboard for many of the connections, I’m going to have to solder several of them. I’ve got sort of a half-baked idea as to how to interface those two things, and the success of the project might largely depend on how well that works.
With any luck, by the end of the day tomorrow I’ll have some photos and maybe a short video. w00t!
Sync Project: Day… 3? 4?
I got a little time to work on the Sync Project today, and it’s, well, pretty much completely done.
I don’t have MIDI Thru, but with only two jacks to work with, a couple of MIDI outputs on my computer, and a pile of old equipment looking shiny to me lately, I’ve come to the conclusion that I might just leave the output jack as a DIN Sync jack. That way the Time Buffer will also serve as a MIDI Clock -> Din Sync converter for any other gear that I get.
Aside from that, it works. I spent a good hour troubleshooting *something*, and having no luck at all, and then suddenly it just started working, with no particular intervention from me. Noise? Loose connection? I don’t know, and that’s a little frustrating.
I’ve formulated this idea that I wanted to do everything using just alligator clips to make it easy to modify later if I wanted to, but I’m re-thinking that. They move around an awful lot, and there’s a ton of noise whenever I go anywhere near them. I might scrap that. I do want to avoid cutting up the Time Buffer cables if I can, such that it’ll be trivial if I later want to sell it or give it away to revert the whole thing by just buying a new faceplate for it. But I should be able to work around that okay. Even if I solder the MIDI leads, I can cut those later without any real skin off of the module’s back. The big question is what kind of wire to use. Stranded would be better for soldering, but the solid stuff I’m using would be nice if I plan to just put the mini breadboard in rather than soldering this all to a real board. I dunno. I suppose I should bite the bullet and both use stranded wire and solder this all up. The downside, other than the pain of transferring the design and mounting another board (although I think there’s plenty of space to do that) would be that I’d probably then want to buy a screw shield for the Arduino so the connections to the Arduino would hold better. But the final result would probably be more reliable while still allowing it to be modified later if I needed to. Hm.
Anyway, the functions tested tonight were the toggle switch to flip between internal and external modes, the toggle switch to flip between “run” and “stop” modes when working internally, the dial to set the tempo when running internally, and driving it from MIDI clock when running externally. It all seems a go. It takes a while to switch between modes, but I can deal with that.
I really want to finish, but it’s 11:40pm and I have work in the morning, plus I don’t *have* a screw shield, plus it would be really impolite to be drilling and dremeling at this time of night. Plus, I don’t even know where my soldering iron and solder are. All in all, it’ll likely have to wait until I’m back from Boston. If I had the screw shield, I’d be tempted to give away my Air ticket for tomorrow night just so I could finish it up.
Sync Project: Dead in the water
You may have noticed that the first couple of updates about the sync project came quickly, and then nothing for a long time.
The problem that I’ve run into is, irritatingly, parts. I placed an order from A1 Electronics here in Toronto for a whole slew of parts, including five case-mounted MIDI jacks. (This project only requires three — MIDI In, MIDI Thru and DIN Sync out, but I figured that if I was ordering some anyway, I might as well get a couple more.) Even though the store is local, they charged the same $20 shipping fee that everyone does, but I decided to go for it anyway, because, well, everyone charges $20 shipping and them being local I’d get my stuff nice and fast, right? RIGHT?
Well, no. It took a little while to arrive, but not *too* long. I opened the box to find my awesome order with all my neat stuff. Well, almost all of it. Instead of the MIDI jacks, there was just a little piece of paper stating that those items were back-ordered.
Since then, I’ve just been waiting. I’ve popped by a few places and nobody seems to have them in stock. I’ve tracked them down at Mouser, but I don’t know if I want to blow another $20 in shipping for a $3 order, especially since this project has already set me back way more money than I’d planned for. (To be fair, a lot of that money is in equipment that will be handy for future projects.)
Okay, so I’ve been waiting. And waiting. And waiting.
That’s pretty much where it’s at. I’ve sent them e-mail, but received no reply.
So I’ve started looking fondly at the Kenton USB Solo that they sell locally through Moog Audio. It’s $279 CAD, and I’d get a very, very sweet USB MIDI to CV converter, with more outputs than I currently get through the Q104 MIDI Interface. I’d also *still* have the Q104, so I could use both simultaneously to increase my outputs to the modular even more. It also has its own LFO, syncable to MIDI. And… it outputs Sync 24, which would make this whole project redundant.
Pros:
- Excellent build quality
- Standalone device wouldn’t take up a space in my modular (remaining spaces in the system are at a serious premium)
- Lots of great features, covers several needs at once
- $279 saves money when you consider that this might help stave off the need for something like Volta (something that can do continuous controller conversion better than the Q104 does)
- Would free me up to not worry about the remaining implementation details of the sync project
- Would leave me with a spare Arduino to play with
- Solving this issue would free me up to get back to working on music, whereas the “project interruptus” seems to be forming an effective psychological block for me
- The $20 shipping might easily balloon as I discover that I need more parts from more vendors (such as a screw shield for the arduino or cable headers from Mouser).
Cons:
- While my implementation doesn’t cover as much overall functionality, the sync part has at least one important additional feature this wouldn’t (an adjustable internal tempo source mode, allowing me to use all the features of my sequencing modules without needing to hook up a computer)
- Buying a device at this relatively late stage in the game feels like giving up
- $279 isn’t peanuts and doesn’t include taxes, shipping, or the 1/8″ to 1/4″ cables I’d need to buy, and is certainly more than just eating the $20 shipping to buy another set of MIDI sockets
- Having patch points on the back of an external box wouldn’t be as handy as having them be jacks in the modular
- Slightly obtuse UI for configuring the device might lead to me not using some of its features (such as the LFO) as often as I could.
So that’s my current dilemma.
I hath returnethed!
Mar 1, 2010 Gear
Today, I moved from our dining room (without most of my gear) back in to my den / studio. You should start seeing more from me again, with any luck. As a side-effect of this move, I was finally able to set up the second chassis and additional modules that I got for the dotcom system for Christmas. They’ve been collecting dust since then, until now.
Here’s a photo of the expanded system, along with a little bit of loopy randomness using all of the new modules together (and a few of the old ones).
Also, hi! :)
(Apologies for the clicks.)
Yes, the patch shown in the photo below is the one producing the clip above. It’s free-running.
Expanded Two-Chassis Dotcom System
Many thanks again to Oksana and Lorne, who built the second chassis for me as a wonderful Christmas gift.