Chord sequencer
  • I was thinking about chords last night and realized that the same approach used in the uModular quantizer to encode a scale into a decimal number would work for a chord. I've already built a uModular sequencer that accepted external values for its steps, so I had most of the building blocks. You encode a one to four note chord and inversion using the encoder which produces a decimal number. Feed the number into the uChord module and it will produce the chord and 1 to 4 gates depending on the number of original notes. At 0 inversion the keyboard starts at C above middle A. The inversion control is a little different than the standard terminology. Since there is only a one octave keyboard, it's not always possible to select the "first" inversion of chords. The uChord has no way to know which note is the root so the zero inversion simply outputs the selected notes. Inversion 1 raises note 1 one octave, inversion 2 raises notes 1 and 2 one octave etc. Inversion -1 lowers note 4 one octave, inversion -2 lowers notes 4 and 3 and so on. Inversions range from -7 to 8 which gives you a couple of octaves up and down. The uChord note and gate outputs are quad signals. There is also an output with the number of active notes. I have also included a quad note envelope control. Of course you can split the quad output any way you like, but feeding it straight into an oscillator is a good way to create chords. Don't forget to convert the signal back to mono at some point. In the demo I use the number of notes output to adjust the volume fed into the quad envelope module. I've use the uModular external input variable chaining sequencer to sequence a number of chords in the demo.

    12-22 12:11 PM updated demo - logic error in uChord
    12-22 1:00 PM updated demo - added more stuff
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    uChord V1.1 demo .audulus
  • Here's one with the chord sequencer feeding the arpeggiator. It's got a very relaxed feel.
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    uChord V1.1 demo 2.audulus
  • I think I may adapt this into a eurorack patch!
  • Thanks! I'm flattered you think its worth adapting. I really like the arpeggiator, thanks a lot for the suggestion. I'm working on one that goes up and down based on a gate signal. I'm still not satisfied with the logic. On the other hand it's nice to have all the outputs at once.

    I recorded about 40 minutes or so, here is a little excerpt of a part that I thought was only a little too long.

    Attached is the patch that I had going out to the modular set-up.
    uChord V1.1 demo 2 copy.audulus
  • That turned out very nice. Really demonstrates how well Audulus interacts with hardware. The arpeggiator is an interesting way to get the feel of a chord structure without a whole bank of oscillators. One of these days I may have to build a rig of my own. Any recommendations on cases/power supplies? Hope you and yours have a wonderful holiday!

    Of course I have plenty of recommendations! But I should also say that there is a lot of variety, so you should still explore the world of eurorack cases for yourself.

    I'll list them in cheap to nicest.

    1) Tiptop Audio Happy Endings kit (84HP x 3U) with uZeus power supply. This isn't a case so much as a set of rales on a desktop stand that you can screw into any standard 19" studio gear rack. Great place to start in terms of price, but seeing all the circuit boards kind of freaks me out and the power bus cables look untidy on a desktop. You can also construct a case out of cardboard with these and they can look quite nice.

    2) Moog Skiff (104HP x 3U) with 4MS row power 30. This is a moog product and is designed to sit at 30 or 60 degrees. It's got nice stained wood end cheeks and the power supply has plenty of headers so you can really pack it with small modules. I own one of these and am pleased with it in all ways except portability. Also if you go with this, you can make up tp 3 rows of these into a glorious tiered desktop case.

    3) Tiptop Audio Mantis case with built-in power supply (104HP x 6U) with built-in power supply. Lots of space, plenty of power the one drawback is that the bottom row is a LITTLE too shallow for an ES-8.

    Honorable Mention - Pittsburgh Structure 96 (48HP x 6U) with built-in power supply. This is the case I use, it is deep enough for any module, but small enough to fit into a padded bag. I think the construction is high quality with lovely woodgrain finish. Downsides are it only accommodates 12 modules and seems to have gone out of production, but the EP and Structure range of cases are pretty sweet.

    tl;dr Tiptop audio has some good options, Moog + 4ms row power is better, and Pittsburg cases are great but kind of pricey and harder to find.

  • Thanks for all the advice! There are so many cases and modules available that it's a bit overwhelming.
  • Thanks for the detailed eurorack case recommendations @RobertSyrett! The eurocrack bug has bitten me since I got the Folktek synth and I've been heavily looking into doing a DIY case which would accommodate that and several other modules. I'm actually going to start down the DIY path for a few of my next modules to get some good utility modules next to it as well as some better soldering skills under my belt. Originally I was thinking I was going to try and save for a bit and pick up the ES-8 right away as my next module, but am opting for a few cheaper/simpler modules to start instead and then will expand to the ES-8 and fancier non-DIY modules. What are some of the eurorack modules in your rig that you couldn't do without?
  • @RileyGuy midi to cv interfaces do a lot of the same work as the ES-8 as far as sequencing goes, so hopefully the midi out update for Audulus comes soon. There are some very nice DIY cases. In fact, the best cases aesthetically are almost always some carpenter who has built his own case out of an old piece of furniture. Or even paper!

  • The Happy Endings case looks like it would be an excellent place to start if you were interested in building your own case.
  • Yeah I'm probably going to get the Happy Ending kit after I've done the proper measurements. I have an old vintage suitcase I'm thinking of converting for the job. My dream idea would be to have it fold out into a 3-tiered system with moving rails or something instead of the standard flat tabletop aesthetic, but I have no idea how I would design it yet. Basically have the bottom two tiers fold down flat when closing the case and when opening the case it would fold up so the middle tier would be at a 45 degree angle, top tier would be vertical, and bottom tier would remain flat. This would be to keep it in line with the design of the frame the Mescaline is currently on, similar to the 3-tier Moog rack system above.
    That's good to know about the MIDI/CV modules as I would mostly use the ES-8 for custom Audulus sequencers and modulation. Can't wait for that Audulus MIDI update!