Super Slow LFO

The Moog Forum Moog Music General Topics Forum
1

Hi all,

I’ve always wanted a ridiculously slow LFO, and I’m wondering a) if my dream is technically feasible and b) has it been realized?

Specifically, what I would love is an LFO with a 5-10 minute cycle time, or even more… I think this would be extremely useful for many different applications, for example you could have a synth filter slowly open over the course of a song, gradually increase delay time on a MF-104, increase another LFO amount gradually, or whatever. It would obviously be very handy for drones, of course, but I think it would be useful for all sorts of music.

So! First question: are there any technical limitions to how slow an LFO can go? Could a synth’s LFO be modified to go super slow?

Second: does such a thing already exist? and/or how slow could you make an LFO go by slewing it with a CP251? I don’t imagine you could lag a 10 second second cycle out to 10 minutes…

Any illumination would be much appreciated! Thanks!

2

Interesting idea. I don’t know if that’s possible. :confused:

3

well i think the slowest setting on the mf103 takes about 1 min to fully cycle. then im sure you could run that into the lag of the cp251 and get some extra time out of it. how much? idont know. if i had a cp id try it and let you know though

4

I just tried ColorForm’s idea, and my ADD got in the way, and I lost interest before one cycle passed…I’m guessing 8+ minutes. :open_mouth:

5

Thanks guys! I didn’t realize that the Phaser’s LFO rate was ten times slower than the usual. Verrrry interesting. For whatever reason it’s the only fooger that I’ve never really had a lot of interest in, but now… Curse you, Moog!

To be honest, I’m still a bit baffled by how lag actually works. I’ll do some reading and post any resultant questions. I think my confusion stems from thinking that the processor is somehow buffering the CV information, which can’t really be the case, right? I’ll study up.

But thanks again for the suggestion. That said, I’m still curious as to what the slowest theoretical LFO is. Anyone?

6

No buffering…I think the lag processor stretches the waveform, but I could be wrong. :confused: Also, The MF-104z has a killer 1000ms delay…that’s different, though, I think.

7

I am not 100 % sure how :slight_smile:, but i think it is different capacitors values, what values I have no clue. But I recall when i had my Model D modified for a dedicated LFO, my tech put three setting on it, real slow to almost normal, kind of slow to kind of fast, kind of fast to really fast. :slight_smile:

8

Yeah, I know different capacitors change frequencies, but I don’t think that’s how the lag processor works. That WOULD make sense though. :confused:

9

thats exactly how i was going to put it lol.

10

A lag is usually the same as a glide.

So put a CV into a lag and it slows it down like a glide.

And yeah, LFOs are possible that can go very slow.

11

A reeeeeally slow LFO is another name for drift back in the good ole 70s.

12

I like the idea but I’m quite satisfied with the LFO on the MF-103. At the slowest rate (0,01 Hz) one cycle is almost 2 minutes:

This enables you to vary the sweep automatically at speeds from one cycle every 100 seconds (0.01 Hz), to 250 times a second (250 Hz).

13

Point taken Maskin, but I’m thinking about veeeeery long pieces, where this would be particularly useful. For example, I once played 24 hours of the note D. A super slow LFO would have been mighty handy. :wink:

So could I modify a CP251 to slow its LFO down? Not that I ever would!! Just curious at this point.

14

Absolutely! You could in theory have five 251’s with the LFO going into the lag processor, out to another lag processor, out to another, and another, and another, etc. Cool! :smiling_imp:

15

Point taken Maskin, but I’m thinking about veeeeery long pieces, where this would be particularly useful. For example, I once played 24 hours of the note D. A super slow LFO would have been mighty handy.

I also make drones and minimalist music so it would definitely be something I’m interested in. I usually use a lot of LFO’s which modulate each other (at slow rates of course) to create sonic continua. :slight_smile:

Any chance you recorded your piece?

16

That would be a nice array of CP’s. :sunglasses:

17

I checked the CP-251 manual. While you can apply a negative voltage to the LFO rate input to slow it down, the minimum rate is 0.03 Hz (~1 per 33 seconds).

For a reaaally slow LFO, you may want to use something different, like a 555 timer circuit. This produces clock pulses, not an oscillator, so you’d have to find a way to drive an LFO with it.

18

You could in theory have five 251’s with the LFO going into the lag processor, out to another lag processor, out to another, and another, and another, etc.

Sorry, but no.
It doesn’t work that way.
At least the way I’m reading your theory. :slight_smile:

19

Latigid on: very interesting indeed. That sounds more promising, I’ll have to check it out. I don’t suppose the Multi Pedal would accept a clock pulse would it? Hmm…

Voltor: I tried just plain lagging a normal LFO but I found that it didn’t actually lag the rate, it basically just attenuated the highs and lows, becuase as soon as the source CV starts to rise or fall the lagged output does too, just slower (hence doesn’t get as high or low). Did you actually get the cycle rate to slow down using this method? I can’t see how…

Maskin: I wish I’d recorded that show!! Still kicking myself. I did, however, record a three hour version of O Canada. Yeah. Really riveting stuff, let me tell you. For some reason it was not a big seller. There’s just no accounting for taste…

Anyone who wants to build me a Super LFO, I’ll pay you (not very) handsomely for it.

20

Okay so I’m not missing the painfully obvious, then? Phew.