How do I fix a ratio between several tremolos?

#1

Really enjoying the axoloti - still very much a beginner at the coding and patching. I am stuck on something I want to do.

I want to apply a tremolo effect to various audio signals which I have been doing using a lfo (blue out) into a VCA. I would like to run some of the trem effects proportionally slower/faster than others. For example a bassy sound 3 times slower than a mid sound, a higher sound 4 times faster..and obviously control it all from the same lfo ( or other source). Have played around with the logic counters but not sure how to then use one to control a lfo rate.

Also would be good to be able to adjust the duty cycle of the trem effect in an audible way. Shorter bursts of sound , longer gaps ...or visa versa. Like on the boss slicer pedal.

Any pointers as to what to try would be appreciated.

richard

#2

Use sel/sel in conjunction with a clock pulse.

Just program all the rhythms you want to have and trigger envelopes. This gives you even more stuff to tweak since you can adjust attack and decay to make the tremolo really subtle or really snappy.

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#3

Thanks for this....never thought about using env anywhere but straight after a midi in. You have opened my eyes. Haven't delved into the sel objects much either- great chance to play with them more and get the hang of exactly what they do.

Its great to get another piece of the jigsaw.Its like a few days ago I wanted the opposite of a crossfade mixer, a kind of cross fade splitter, and then I suddenly realised I could use pan.

Appreciated,

Richard

#4

Yeah Envelopes are the bomb :smile: I'm using them for similar stuff and also for modulating filters, so you get some kind of seuquenced auto wah.
If you want to combine alle the envelopes it might be a good Idea to let them go to a K rate mixer, so you blend the different pulses smoothly. Like dis:

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Once you get into the whole modular system of axoloti you can do much greater stuff than any Boss Slicer because YOU decide how your device works!

#5

To get a square LFO with PW, I would pass a descending saw through a comparator type of object. I'm not able to check exactly what objects are available right now, but I'm sure there's something? That would give you variable PW if you wanted a square tremolo sound, but it sounds like you're happy with the envelopes?

Also, if I remember correctly, the LFOs follow a (subsonic) musical scale. So every 12 units of change on its rate represents a doubling or halving of the frequency. Useful, eh?

#6

Thanks Sir P. No I am definitely up for more ideas and suggestions. like to try what you are suggesting but I dont know anything about how comparator objects work either. Ill have a dig around.
I had some success ( and a lot of fun) with the sel-to-env approach but quickly got distracted into the possibilities of patterns meshing in and out of each other. Theres a whole world of potential in this. The ramps of the env do have their own feel - quite different from the swell of a sine wave. So id love to explore 2 or 3 ways to try this - as each would have its own character. So more ideas please.

For me , getting a unique character into things is what its all about. I have a few synths and offboard gear and have no interest in replicating any of that with the axoloti. I want to find things that only it can do -with a signature feel to it. Out od the 30 or so patches ive made so far maybe only 2 or 3 have it. Im not sure if that ratio increases the more you know? Im very happy with it and know I havent explored much of at all yet.

#7

Oh and thanks again Blindsmyth. I havent tried the blue mixer on several envelopes yet. looking forward to doing that. Would never of thought of it. and trying your wah ideas too.

#8

I'm not even 100% sure the Axoloti has what I'm talking about amongst its stock objects as I can't check right now (because I'm at work, ahem). A comparator is how PWM is done in the analogue domain, it outputs a high if one input is higher than the other and a low if they're the other way around. By comparing a saw or triangle to a fixed reference, you can create a pulse wave that is proportional to the ratio of how much of the waveform falls above or below the reference. Then you can vary the reference to change the pulse width. Hope that makes sense. Anyway, I'm going to have to try it when I get home because I want to see if it can be done with the stock objects.

#9

you mean something like

math/<


or 

math/<c

(if you want a built in dial)

e.g.

#10

Of course! I was thinking in analogue terms too much, it seems obvious that it would be there as < and >.

#11

Thanks for this idea, Sir P and Technobear. will try that too. looks a good one. Would I still use an env obj? or can that yellow go stright into VCO blue in?

Also noted, I should start using scopes and meters more to see what is going on.

richard

#12

I assume you meant VCA? For a choppy type of tremolo you'd want the yellow signal straight into the VCA. Yeah, yellow outputs can be connected to blue inputs and they get automatically converted. 0 on a yellow signal becomes 0 on a blue signal and 1 becomes 64.00. You could connect the yellow signal through a k-rate lowpass filter and then onto the VCA, this would give you a smoothness control that lets you soften the effect slightly if you desire. Some guitar tremolo pedals have exactly this control (sometimes called 'shape' or something similar).

#13

No problem :slight_smile:

This is a great thing to know thx! But If you want to set ratios like 3/2 (Triplets) wich would aproximately be setting the lfo 7 Semitones higher 7 (perfect fifth) you will have the Lfo's drifting because in our tempered system the musical invervalls are not based on these simple mathematical ratios.

So I think hooking up controlls to the blue inlets of Lfos and multiplying them with whole numbers of math/*c might be better I guess.

This is a cool thing I didn't know either, nice.

#14

That's true, but don't forget that you have two decimal places of precision too, so you can get cents. 7.02 is really really close to a true perfect 5th, but I think there would still be a tiny bit of drift due to rounding to only two decimal places.

I'm not sure I follow the bit about multiplying a control signal by whole numbers, can you give an example?

I just had an idea to avoid the drift: hardsync!

You'd need three LFOs for a 3/2 ratio, one square wave master and two slaves of whatever waveform you want (as long as it has a reset input). The master is connected to the reset input of the two slaves, you then have one slave set 12 units faster than the master and another set 19.02 faster. This gives you a nice 1:2:3 ratio, which might drift very slowly, but it's being synchronised every beat of the master.

#15

:doughnut: I have tried the lfo/sawdown then math [larger than]c with the k lowpass filter and I like it a lot ( and yes I want the dial). Thanks Technobear and Sir P - lots of uses for this.

Back to my original question. I still think I'd like to be able to fix a ratio triggering the logic counters. The reason is that even if you blocked out a whole row of boxes in the sel16 the env clicks on and off 16 times and this makes a real qualitive difference to the sound. percussive and ratchety (- which is nice to know if thats whats you are after). There is not a way to hold the trigger open for the duration? ( im probably using the wrong terms here). Obviously if I just wanted one i'd run it 16 times slower but id like several at different ratios. Would this need some kind of new object? would a hold option on the sel be good? or a multiple lfo output object with a master speed control? both out of my league but im interested in the discussion. Is my desire to have something like this a bit too singular?

I have really benefitted from all the discussion so far. Thanks again.

#16

You mean so that several consecutive beats in the sel16 just hold the envelope open instead of re-triggering on each? Try using an AHD envelope instead of an AD.

#17

Hi ah I don't know if I choose the right words here :wink: I remember it from a patch I made with recording audio into tables and having it played back by several tables at different speeds. I did this by multiplying the the frequency of lfos that drive the tables before the blue inlet. I wanted to have only different octaves, but I remember also getting intervalls of the harmonic scale multiplying with math *c, wich would be what you need in order to get clean triplets and dotted notes. (or even more experimental polyrhytmhs like quintuplets etc)
Unfortunately (or rather fortunately :slight_smile: ) I don't have time this weekend, playing two gigs, but I can look this up next week, I guess it could be a solution what @Zedkah looks for.

#19

Ah, I've just been looking at the LFOs and there are ones with linear frequency input. These would allow what you're talking about, you could multiply the frequency signal by an integer and it'd give you an 'overtone' of the base frequency. This is why linear frequency control can be useful, you can define intervals with multiplication or division. Exponential control only requires addition or subtraction to define an interval, but when you're working with 12et it can be hard to get the precision needed for true harmonic intervals.

#20

OK, I will try that. But the hold value is a time so that would need to be re adjusted for faster masters lfo speeds. it would simply hold open over a white square if set too long- or would it? I will try it .
thanks,

richard

#21

No, the AHD doesn't have a hold time, but rather stays open for as long as the gate signal is high.

You're right to be confused though, IMO it's misnamed, it's what would normally be called an AR envelope.
The name AHD implies three stages with three controls, with the hold time being an adjustable wait before the decay begins. But the (misnamed) AHD object rises at the attack rate when the gate goes high and stays there until the gate goes low and then drops at the 'decay' rate (which is really a release time since it comes after the gate goes low).