I put together a primer on turning the Octatrack into a genuine sound-on-sound looper, in the Frippertronics tradition — a loop that’s always overdubbing and evolving rather than something you trigger and walk away from. It uses a Flex machine feeding back into itself rather than the Pickup machine, which gives you the OT’s full effects and scene system inside the feedback path. Covers the gain-staging to keep loops stable, a reference for which BPM and loop lengths play back clickless, a delay-based trick for vibrato and filtering, and using the crossfader as a real-time performance tool where every move gets recorded into the loop itself. PDF and reference spreadsheet at the links.
Thank you. Very detailed and easy to read document. Cheers!
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I currently have a pair of loops going. One is 63 trigs long, one is 64. Running at 275.6 bpm. Does a nice Steve Reich-esque phasing.
I see that folks are looking at the pdf, but not the xlsx. Let me know if you have trouble accessing either. I had tried to upload them here, but the uploads kept failing.
Nope, looks good. I should probably prune that directory a bit.
I missed quite a bit. Been busy lately.
BPM-Trig, Clickless Loops, EQ-Filter Frequency Mapping, Tuning-LPF/HPF/BP, Phaser Notes, Tuning-Flanger, Tuning-Comb Filter, Chorus, LFO Speed vs Microtiming, LFO Designer In-Between Values, Tuning-RM, Tuning-SRR, Compressor Makeup Gain, Precise Values-BRR, Sound on Sound (Frippertronics) Looping, …
Still planing on consolidating all of your research into 1 file? I understand that it’s ongoing, don’t know how that would work…but I think it would be a goldmine for some folks.
Incredible work you’re doing here, and posting your observations is very generous.
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Yes, I actually have drafts of a bunch of chapters and an outline for the project.
The sound-on-sound chapter is actually the first one I started. The “research” goes back about a year to when I first got my Octatrack. I was inspired to update it because I learned some new details about the inner workings if the Octatrack. That it works in 16 sample chunks instead of 64 sample chunks opened up more BPM/RLEN combinations.
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what in the hell is your background?? i really dig your research with this stuff. i have an mk2 i barely have touched. owned it since march 3, 2023. i pull it out every now and then and mess with some things and put it up. what made you get this thing? i will never get rid of mine, i read more about it than use it. about to change that soon. but too many projects currently.
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Background is applied math and music (guitar, bass, moog, …). I studied a bit of computer music in college and then got back into the computer music stuff a few years ago as a hobby. I started building my own plugins, but then realized I much prefer hardware.
I honestly got the Octatrack on a whim. I had a few other Elektron boxes, but wasn’t really sure what i’d use the OT for. It is now the centerpiece of my music room! And, honestly, I want to know everything about it.
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Looking forward to it. Much appreciated.
I had to read the chapter “Clickless Looping: The Math” in your PDF to understand. Impressive!
Pondering: I wonder if Igor Vasiliev has ever used an Octatrack. Have you ever used his SoundScaper iPad app with its bit-masking tricks? Wild sample manipulation. Link. He has some newer similar apps too.
This is great. I read the primer and will make a template for myself based on it.
I dont think sound on sound recording is useful for me personally regarding my own ‘finished works’ ie: stuff I release, but for experimenting and noodling around, really fascinating stuff.
Thanks so much for sharing your findings.
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Bumping this because I updated the primer and the spreadsheet.
Good news! More BPM/RLEN combinations were worked out to be clickless.
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This rocks
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Wow, this is great… I played around with something similar a while back, but you really took it to another level here.
I can’t get the thing with the delay to work. Play trig set back 4 steps and a delay with time=64 on it. Every time the buffer restarts recording, it erases the contents. I don’t ever hear the buffer at all. What might be going wrong here?
Hmm. Is the record source set to the same track?
Great work! I take it there’s really no way to do half/double speed or reverse like you would on a looper pedal since you would have to be able to change both rate and sequence length at the same time?
How would you handle easily arming or unarming various loop tracks? You would have to manually change stuff in the record settings rather than toggling the record triggers on and off since they’re needed to keep the loop going?
Reverse is harder … the typical approach uses two delay buffers. Double/half are also tough since they change the length of the buffer. When I want those effects I usually setup a another track that samples from the sound-on-sound buffer. Then you can use the usual OT tricks with microtiming to get the shifts.
For arming/disarming, I use a MIDI controller. But I also like to leave the delay lines open and just mute the inputs. That allows them to keep evolving.
There are a bunch of fun extensions that I didn’t cover in the writeup. 
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yup. It works fine with both the play trig and rec trig on the 1. But when I try to switch the play trig to 13 and add the delay, every time the rec trig triggers, it clears the buffer. I can still see the waveform being recorded on the AED. Which is odd because the playhead in the AED is clearly going over the recorded audio for those 4 steps before the rec trig, but I don’t hear it.
Interested in these if you feel like elaborating!