Rytm self contained super LFO

Elektron Gear Analog Rytm
#1

I’ve recently started making use of the control inputs of the AR, and since I don’t have any eurorack (yet), I figured since audio is basically audio rate cv, I could use one of the individual outs (SD) as a source of CV.

What I do is connect a cable from the SD (any of the bottom four would do) out to Control in 1 whilst disabling SD in the main outputs. Then, set the SD machine to DVCO (i find fm settings with bar underneath work best), turn the pitch way down, set LPF to very low. Then turn on CV for that control input, and tinker with the settings til it oscillates in a desirable range when playing the VCO, (I find 450ish for 0 and 500ish for max works).

Then set mod destinations for Control in 1 to whatever I choose (filter freq, pitch, volume, other machine settings) and from there I can mess with the VCO to give me complex LFOs that are in sync with the sequencer and controllable through perf macros and other stuff and also able to control 4 different parameters across the whole machine. I feel like this opens up a lot of possibilities

BEFORE YOU DO THIS
While this works pretty damn well im concerned that this was not the intended design and I have no idea if this could damage the machine (so do so at your own risk).

I ask those of you who know about this kind of stuff, if this could potentially lead to damage?
I am particularly concerned about accidentally setting the control in to expression pedal mode whilst connected, sending a voltage into the output (do i need to worry about this?)
Also I am using a TRS cable, I think TS cable would work better for this maybe (ive got no idea) but could this also lead to problems?

Thanks!

22 Likes
#2

very nice, it could maybe be used like an envelope follower too…hmmmmmm

3 Likes
#3

This is ace. ACE!!!

Awesome find! I doff my cap, squire!

4 Likes
#4

Not tried this yet, but just want to say thanks in advance. Nice discovery.

1 Like
#5

Don t worry you won t fry anything like that. Balanced shouldn’t matter either.

Cool method!

2 Likes
#6

Though not completely sure about the accidental expression pedal setting…

1 Like
#7

Damn this is a really great idea. Just got a Mk2 a few days ago and I’m going to use the hell out of this trick. Will have to do some experiments with Tom tracks to see if I can get a useable sine-ish wave out of them.

Oh. Actually a sample of a slow sine could be perfect, and would mean it could go on any track. Or a sample sine blended with a slowly fading in noise machine. And trig conditions on the “lfo” track. God the possibilities…

Thanks a bunch for this. Has potential to drastically increase modulation possibilities, without having to mess with external midi. Amazing.

2 Likes
#8

Great idea, now that I think of it, using single cycle waveforms, then repitching and resampling as you need… would be probably far more controllable. Imagine using two separate tracks going to each of the control ins… then with trig conditions, scenes… must try this

2 Likes
#9

4-Audio 1 [2021-06-09 104029].aif (8.8 MB)

so doing this with single cycle waveforms works very well, I made some LFO rate triangle waves as a SCW, then used that on an “LFO track” with trig conditions, adjusting the pitch and start point per step to modulate two identical high hat tracks decay and overdrive, extremely easy to make wacky rhythms using this method and Im sure it would work for a whole other realm of applications…

First two bars are without the “LFO track” rest is with

5 Likes
#10

I attempted a similar trick in the past, however I remember being disappointed because I believe the RYTM outputs are not DC-coupled; meaning that a LFO at a very slow sub-audio rate (like below 1Hz) will be filtered out and basically no signal will be present at the RYTM’s individual outputs.

I had this idea to use a square wave as a single-cycle waveform and set the start-end points so that only the positive half of the square wave would loop, this way I could have a constant CV controlled by the track’s volume, but this would obviously be a DC signal and was, unfortunately, filtered out completely.

But if someone could prove me wrong, that would be awesome, so many possibilities!

1 Like
#11

While we’re on the topic, and not to stray too far off subject here; but I’ve also been wondering what sort of eurorack modules would prove to be most useful for accomplishing this sort of thing in a way that would be safe for RYTM MKII, A4 MKII or Heat’s MKI or MKII’s Control inputs.

I am very much interested in sending the individual live analog audio output of RYTM and A4 into the rack and have it processed/controlled there… then sent back out to affect another instrument or the same one in a sort of inerplay via the Control input. Also to have just one or two tracks from either A4 or RYTM affecting some parameters of the Heat seems like it could quickly get very interesting.

Envelope follower seems obvious - but what features would be most important? additionally, what other types of modules besides that?

#12

I had a few minutes to try this out last night, but wasn’t able to get satisfactory results. Or, at least not predictable results. It was like a crazy random noise sort of mod. Which is useful! But not what I was expecting from a sine wave.

Going to take another stab at it tonight. I was using the hi Tom track as the mod source, will try again using a track with its own individual output, rather than a trs/dual one. Will also get a slower sine sample to work with. Actually that may have been the whole issue…

Interesting note about the dc coupling. I’ll report back when I have some useful information to share.

#13

Yeah after doing this more I’ve found it’s pretty limited as it breaks down in effectiveness and predictability once you go slower than a couple hz. I guess you may as well use a midi cc to a perf macro for the slower stuff and this could be used more as a sound design tool

#14

I really like it, to experiment.

Took a bunch of waveforms in the sample pool and let the lfo change sample slots.

Lot’s of movement after that, while modulating pan, osc balance, filt env and amp ovr.

1 Like
#15

Have been experimenting using internal kick machines as a modulation source. Definitely works as expected, although I haven’t tried anything at a lower frequency (samples) than what the internal machines are capable of. There is a lot of potential here even without slower sources.
Have been using the 1st track as the mod source but you could even set up say track 3 as control 1 and track 4 as control 2 with a splitter like the one Elektron makes. I believe this would limit you to one source playing at a time because the split tracks share a vca, but still, lots of worthwhile things to do like that. I predict this will keep me busy for some time.

#16

Also, the cv inputs seem quite limited in regards to audio-rate modulation. I am sure that the modulation from cv inputs are implemented in the digital domain and, judging from my experience trying to do some cool filter FM using the individual outputs and getting unpleasant results, I think there is quite a lot of aliasing with a cv signal at audio rate. But for atonal and distorted stuff, it can be cool.

I think the CV inputs are best used with DC and sub-audio rate signals, while the outputs are only suited for audio rate signals. The overlapping sweet-spot between the two is quite narrow, unfortunately.

#17

I posted some stuff like this a while back including using the sep out to CV in and a knob box:

4 Likes
#18

I’ve been designing some simple diy modules to do something very similar to the goals you mentioned but haven’t finished them.

I settled on an envelope follower circuit and a quirky pitch tracking circuit (similar to the pitch tracking on the Korg MS20 external signal processor). My envelope follower is similar in design to the typical side-chain envelope followers you’d find on a studio compressor, but I also added a little S&H circuit that grabs the envelopes peak - a sort of “velocity extractor” for the signal.

I realized later you can achieve the same thing (i.e., envelope and pitch followers bundled together) with Analogue System’s RS-35 module, which is also very similar in design to the Korg MS20’s external signal processor (I think I remember reading that the pitch tracking is the same tachometer-based frequency-to-voltage conversion). I’d also check out how to do frequency-to-voltage conversion with Doepfer’s PLL module (A-196), I think it’d be quirky in a different way.

Outside of extracting amplitude and/or pitch information, there’s a whole world of triggering lfos, envelopes, and complex modulation signals using external audio, but that probably begins with something that can convert an audio signal into a simple gate or trigger. For this, maybe run the signal’s envelope (from an envelope follower) into a comparator.

1 Like
#19

nice one. I’ve got the MoogerFooger CP 251. That’s a fun option too!