LFO. Vibrato effect

System 55 • System 35 • Model 15
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Rarecomponentadsr
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Joined: Mon Aug 24, 2015 5:08 pm
Location: Derbyshire England

LFO. Vibrato effect

Post by Rarecomponentadsr » Fri Oct 16, 2020 6:17 am

I posted a while ago on this subject but am still experimenting.

Looking for a definitive, industry standard LFO musical vibrato

I’m taking a low frequency sine wave from a 921 and feeding that to a VCA top left input. From the top right output I feed that to the attenuator and switch on a CP3 which is connected to the CV for depth of vibrato.

With a 911 I can control delay of the vibrato thru the VCA. This works fine.

But hand on heart I’m not impressed with the overall result. Sure, I get vibrato and such but it’s seems there’s just not enough bite to it. It seems weak and watery. Even with a large amount dialed in to the CV I just don’t get the clean and good effect I’m looking for.

Am I missing anything here or is there a better way to achieve musical vibrato ? Should the VCA be left open a little etc etc (I don’t want mad psycho LFO effects)

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MRNUTTY
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Re: LFO. Vibrato effect

Post by MRNUTTY » Fri Oct 16, 2020 10:31 pm

Use the 911A to get some delay before the 911 env into the vibrato effect. The 911 exp attack's initial slope is too high to start at key down time. A linear attack slope is better imho. Go into the AC Mod input of a 921B to eliminate any DC component. You got the rest fine.

Try a triangle wave too. There's constant pitch shift with tri. Sine is less effective since pitch shift is also sinusoidal.

A little delay doubling (20-80ms) with was really accentuate a vibrato effect with a chorusing flanging sound too.
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
System 55 and Minimoog clones, personally modified to bring them closer to OG spec(s).

Rarecomponentadsr
Posts: 99
Joined: Mon Aug 24, 2015 5:08 pm
Location: Derbyshire England

Re: LFO. Vibrato effect

Post by Rarecomponentadsr » Sat Oct 17, 2020 6:49 am

Thanks for help.... 911a tip, I never thought of that.

I’ve been doing more tests.

It seems that the sine wave effect on the CV just doesn’t bite enough.
Yes I know I can add more, depth etc, but that seems to just muddy everything. I tried the triangle wave which is a little different but same effect.
I made a patch lead up with a blocking DC. Elec capacitor installed for some LFO patches to eliminate D.C. problem.

It could be I’m expecting too much from the modular system as compared to current tech regarding vibrato or I just need to keep experimenting and it’s probably the latter.
As an example the Arturia Mini Moog has dedicated LFO in the “back panel”
and although very fiddly and hard to control, it gives a full and effective vibrato that I would like.

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MRNUTTY
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Re: LFO. Vibrato effect

Post by MRNUTTY » Sat Oct 17, 2020 8:19 am

Rarecomponentadsr wrote: Sat Oct 17, 2020 6:49 am Thanks for help.... 911a tip, I never thought of that.

I’ve been doing more tests.

It seems that the sine wave effect on the CV just doesn’t bite enough.
Yes I know I can add more, depth etc, but that seems to just muddy everything. I tried the triangle wave which is a little different but same effect.
I made a patch lead up with a blocking DC. Elec capacitor installed for some LFO patches to eliminate D.C. problem.

It could be I’m expecting too much from the modular system as compared to current tech regarding vibrato or I just need to keep experimenting and it’s probably the latter.
As an example the Arturia Mini Moog has dedicated LFO in the “back panel”
and although very fiddly and hard to control, it gives a full and effective vibrato that I would like.
What value did you use for the DC BLocking cap? Can you get a peak to peak measurement of the vibrato waveform input to the VCO?
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
System 55 and Minimoog clones, personally modified to bring them closer to OG spec(s).

Rarecomponentadsr
Posts: 99
Joined: Mon Aug 24, 2015 5:08 pm
Location: Derbyshire England

Re: LFO. Vibrato effect

Post by Rarecomponentadsr » Sun Oct 18, 2020 5:22 pm

Having checked it’s not an electrolytic I put in the patch lead it’s a .47 cap
to cut the D.C.
However , trying different patch cables I’m still not happy with the LFO signal.
I’m using an out of the system Dot.Com oscillator for the low sine source and maybe it’s not exactly balanced to the Moog VCA ..I believe the Moog 921 was a likely LFO source .

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MRNUTTY
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Re: LFO. Vibrato effect

Post by MRNUTTY » Mon Oct 19, 2020 9:42 am

Rarecomponentadsr wrote: Sun Oct 18, 2020 5:22 pm Having checked it’s not an electrolytic I put in the patch lead it’s a .47 cap
to cut the D.C.
However , trying different patch cables I’m still not happy with the LFO signal.
I’m using an out of the system Dot.Com oscillator for the low sine source and maybe it’s not exactly balanced to the Moog VCA ..I believe the Moog 921 was a likely LFO source .


Oh tremolo? So, it's volume you're after not pitch? Lol... that's a bit different :-)

Couple of things to check; bi-polar waveforms and VCA behavior with negative CV input valtage.

Yeah, use 921 AUX out - it has larger peak to peak voltage than the individual audio outputs.
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
System 55 and Minimoog clones, personally modified to bring them closer to OG spec(s).

Rarecomponentadsr
Posts: 99
Joined: Mon Aug 24, 2015 5:08 pm
Location: Derbyshire England

Re: LFO. Vibrato effect

Post by Rarecomponentadsr » Tue Oct 20, 2020 10:57 am

Oh..no... I send the low sine wave into the vca controlled by a 911 to act as a delay or fade in /out for the Sine LFO signal. It is def pitch vibrato and not Tremelo I’m dealing with.
As mentioned with Dot.Com Osc as source sine wave and then going into VCA maybe the sine wave is being changed or flattened, weakened or something .
I need to do some more tests using a 921 as source LF sine wave and bypassing the VCA for the moment.

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MRNUTTY
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Re: LFO. Vibrato effect

Post by MRNUTTY » Tue Oct 20, 2020 9:09 pm

Rarecomponentadsr wrote: Tue Oct 20, 2020 10:57 am Oh..no... I send the low sine wave into the vca controlled by a 911 to act as a delay or fade in /out for the Sine LFO signal. It is def pitch vibrato and not Tremelo I’m dealing with.
As mentioned with Dot.Com Osc as source sine wave and then going into VCA maybe the sine wave is being changed or flattened, weakened or something .
I need to do some more tests using a 921 as source LF sine wave and bypassing the VCA for the moment.
Lol! Ok.

The log attack envelope starts fast, you could negatively offset the VCA so the 911 opens the VCA further with a gentler slope.
VoyagerEB, Minitaur, LittlePhattyII, 4xSlimPhatty, Sub37, MF[2x101,2x102,103,104M,105,105B,105M,2x107,108M], 3xCP251, XV351, MP201;
System 55 and Minimoog clones, personally modified to bring them closer to OG spec(s).

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