Is it possible to change the starting point of a sync'd LFO?

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DontBelievetheHype
Posts: 148
Joined: Fri Feb 20, 2009 10:19 am

Is it possible to change the starting point of a sync'd LFO?

Post by DontBelievetheHype » Sat Nov 07, 2009 8:41 pm

When using the MP201 MIDI synched to Ableton, I often find the LFO to start on the opposite end of the sweep that I would like to use; ie a triangle starting on the 1 will start at the top of the LFO and sweep down, whereas I'd like it to start from the bottom and move up(and then back down, up, etc- not looking for a ramp in this case); its always just a half step or so behind from where I'd like it to be.

Ive looked through the manual and couldn't find anything about this. Is there something in the MP201, or maybe Ableton would allow me to move the LFO starting point back a notch, or the starting point of MIDI sync in Ableton, something along those lines?

Any suggestions are welcome and appreciated!
Synth bass guitar rig including MS-20 filter clone, Paradox TZF, MF101, 102, 103, 107(x2), CP-251 and MP-201

ebo
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Post by ebo » Sun Nov 08, 2009 8:41 am

I have the same problem .I worked with Logic.When i started a song.everything was ok,but when I started a song in the middle the lfos are running mad.they are no in time.I recorded my foogering only at the beginning of a song and take it later to the right place. Ebo







2xMF101,MF102,2xMF103.2xMf105,Mf105B,Mf107.MP201,CP251,VX351,
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DontBelievetheHype
Posts: 148
Joined: Fri Feb 20, 2009 10:19 am

Post by DontBelievetheHype » Sun Nov 08, 2009 9:16 am

Im actually not having a problem with the LFO's keeping in time, just the starting point of the LFO; i want it to start from the bottom instead of the top basically.
Synth bass guitar rig including MS-20 filter clone, Paradox TZF, MF101, 102, 103, 107(x2), CP-251 and MP-201

Bryan T
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Post by Bryan T » Sun Nov 08, 2009 1:56 pm

DontBelievetheHype wrote:Im actually not having a problem with the LFO's keeping in time, just the starting point of the LFO; i want it to start from the bottom instead of the top basically.
It would be nice if you could reverse the max and min values of the LFO. I had forgotten that the parameters were 'amount' and 'offset.'

Amos
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Post by Amos » Sun Nov 08, 2009 9:03 pm

what you're looking for is control of the LFO Phase. This is not available yet, but v2.0 did not update the LFO very much.

I have a list of improvements for the LFO engine... I will try to add LFO phase control to the next firmware update, although I can't estimate how long it will be until then.

Cheers,

Amos

DontBelievetheHype
Posts: 148
Joined: Fri Feb 20, 2009 10:19 am

Post by DontBelievetheHype » Wed Nov 11, 2009 3:51 am

Good to know I'm not doing it wrong at least :p I'm very excited about future firmware releases, but I'm keeping busy with the new functions in 2.0 and for the time being I'm able to approximate the LFO modulation Im seeking by riding the exp pedal with the new EG, but would be extremely happy (and grateful! :D) to see 'LFO phase control' implemented into the next firmware release! Thanks for taking the time to clear that up for me Amos.


Can 'phase inversion' or the like be easily accomplished externally? A voltage flipper or something? I don't really know where to start looking, but imagine some sort of a/b style box accepting the MP201's CV, that when switched would create a mirror image of the input voltage, or phase flipped output or something like that. I've seen phase switches in audio blend circuits/pedals to combat phase cancelation, but not sure if this is related and/or applies in any way to DC voltages.. Can anyone tell me if I'm on to something.. or off my rocker? :)
Synth bass guitar rig including MS-20 filter clone, Paradox TZF, MF101, 102, 103, 107(x2), CP-251 and MP-201

Amos
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Joined: Wed Jul 23, 2003 3:11 pm

Post by Amos » Wed Nov 11, 2009 3:09 pm

Yes this would work. In analog terms, what you want is an inverting amplifier with unity gain. You could do this "flipping" with the CV mixer on a CP-251, for example.

In fact you could do this with a CP-251 and use only one single LFO channel from the MP-201. Run the analog output from the MP-201 to the 4-way mult on the CP-251... then take one output from the mult and run it to one of your CV destinations (this would be the "non-inverted" LFO), then take a second output from the mult and connect it to input 3 or 4 of the CV mixer on the CP-251... then connect the "minus" output of the CV mixer to your second CV destination, and this would be the inverted LFO.

DontBelievetheHype
Posts: 148
Joined: Fri Feb 20, 2009 10:19 am

Post by DontBelievetheHype » Sun Nov 15, 2009 7:28 am

Hmm, I think its time to bite the bullet and sell off some unused and/or overlapping gear to fund a CP251. I wonder if the LFO would remain in sync during the phase flip, or if there are some sort of losses to account for or anything. I've been set on getting a CP251 at some point anyway, so I'll report back my findings once I get one in my hands.

Thanks again for the info Amos.
Synth bass guitar rig including MS-20 filter clone, Paradox TZF, MF101, 102, 103, 107(x2), CP-251 and MP-201

DontBelievetheHype
Posts: 148
Joined: Fri Feb 20, 2009 10:19 am

Post by DontBelievetheHype » Thu Jan 07, 2010 11:22 am

Ok, I've figured some things out-- some of this may have been obvious to many, but being relatively inexperienced, I'd never experienced MIDI lag, phase adjustment etc.. As long as you don't change the subdivision of the MIDI synced LFO while in sync, the phase of the whole and dot subdivisions start in the usual spot- Im unaware of any settings on either end that may account for this, though if there is I'm all ears!

I got the CP-251 and tried the trick Amos explained, but it just produces a Saw out of a Ramp, -5 triangle out of a +5 triangle, etc, but still in the same phase when you level it with the offset. This is somewhat inconsequential though because it turns out not to be the problem I though I'd been experiencing.. One other issue Ive found that threw me for a loop is that the MP-201 does not phase lock to the start of a MIDI clock if you change the subdivision while moving, instead it will latch on to different parts of the loop, not necessarily where it started-- ie from a whole note, to other subdivisions and then back to whole note- starts opening on the kick, and when you get back to it it's opening after a snare instead.

I've spent a lot of time with the MIDI synced lfo's lately and compared recordings of beats and the LFO'd filter modulation and the visual representation helped me wrap my head around it-- when MIDI synced to Ableton there is a significant lag, and its especially noticeable on the slow in-you-face filter modulations I like to do.. I tested it with the lone piece of MIDI hardware I have at the moment, and the MP-201 is basically dead-on, no real noticeable lag to speak of, so its definitely an issue on the Ableton/computer side and not the MP. I looked around online and it appears that Ableton is somewhat known for this so Im going to try and adjust settings in it.



Amos - if a phase parameter makes it into a future update, is there a chance of a 'phase locking' option for more flexible synced modulation & subdivision changes-on-the-fly?
Synth bass guitar rig including MS-20 filter clone, Paradox TZF, MF101, 102, 103, 107(x2), CP-251 and MP-201

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