Slowly open filter with LFO


I want to slowly open a synth track filter with a LFO. I want the filter to go from 0 to fully open during 64 steps. Tried a lot of waveforms and step combinations, but no lucky…

Any hints ?

Don’t have a DN, but on other devices you would …

Select Ramp LFO shape
Set to Free Mode
Set factor of speed x mult to 128/8 (16)
Set Filt Freq low
Target LFO to Filt Freq
Enable a single LFO reset(retrig/restart) using a p-lock with a 1st TRC condition on step 1 (assuming same functionality as other boxes for resetting LFO phase)

The LFO speed is 128 for a normal shape over 1 bar, so divide by 4 for 4 bars and half half again for using only the first half of LFO shape - can also be a Tri shape (if no ramp available) if you divide factor by 2 again to get a quarter of the shape over 4 bars


For a different flavor, couldn’t you use the exponential LFO shape and set the speed to a negative number? As I recall, there’s a way to make the LFO go in reverse. Anyway, that would preclude the need for the extra speed division. However, I do like that idea of working with LFO timing to achieve different results.

As an aside, with various tweaks to the filter envelope, couldn’t you also use that to achieve the desired result? long attack, zero decay/sustain/release. Adjust the attack to get desired result.

Ah - but using the envelope, it would get triggered every time. Nevermind. I kept thinking of it with respect to a pad sound that only gets trigged once. In which, case the envelope could work too, I suppose.

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you could disable the filter trigger except on the first note using parameter locks


hey, mate. i think i know what you’re trying to achieve.

press FUNC+TRIG, then go down to PLAY MODE and set it to POLY M.LFO

i hope this is what you meant =)


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Ok, so I’m trying to slowly open the filter using the LFO on my DT and it’s driving me bonkers. I’d like the filter to open over the course of 256 steps (16 bars) at 123 bpm. To wit:

Filter freq is set low
LFO SPD is ridiculously low (like 0.10-ish)
LFO MULT has varied - this is where I think I’m getting stuck
WAVE is set to ramp
MODE is set to free
I have a “trigless” trig on to step 2 (step 1 is the actual note trig) with a 1st TRC to turn both the FLT.T and LFO.T on

I seem to keep getting different results each time I start the sequence. In most cases, the filter slowly opens but inevitably and abruptly “drops”/closes up before the end of the 16 bars/256 steps - presumably because it hit the top of the ramp? Is this just not possible at the tempo and step length that I want?

My sanity thanks you in advance… :wink:

If the product of
speed * mult
needs to be 128 over 1 bar (16 steps)
for a complete cycle of a regular lfo shape

then make it 64 for the first 180deg of a ramp shape over 1 bar

you want it to take 8 bars, so divide by 8

you need Speed x Mult to be 8

1 , 8x
2 , 4x
4 , 2x
8 , 1x

ensure you have properly reset phase of LFO to 0deg on step 1


As well as following @avantronica’s advice, this is part of your problem. Your trigless trig should be set to TRG or ONE to start the LFO correctly:

You see how FRE is unaffected by trigs :slight_smile:


That did it! Sanity restored… @craig setting the MODE on the trigless trig to ONE started the LFO properly. A debt of boundless gratitude to both of you for the help!


Why not just live record the parameter changes? It’s only 64 steps.

That was my Plan B. I wanted the filter to open over the course of 16 bars/256 steps, which would have been a headache of trigless trigs set to various conditions.

Well that’s certainly different. I think I missed the 16 bars portion of the post. Anyway glad you found a solution. :slightly_smiling_face:

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