Question about the lfo's

I really like the lfo’s in renoise, but i ran into some trouble with it.
When i automate a parameter of a vst instrument with the native renoise lfo i get great results.
When i saved the patch however, it gets saved with the parameters in the position the lfo puts it.
So every time i save the patch it gets further and further away from the original. I can put an automation value of the parameter controlled by the lfo in its orginal position in the automation lane at the beginning of the track. So when i disable the lfo’s, i’ll get the original patch again. Or i can just load the patch from disk. But do i have to do this every time before i save the project?
When you save the project, all vst’s get saved as well. So when i open the project again, it will not start with the original patch, but with the lfo controlled parameters at the position they were at the moment i saved the project?
Is there a simple way to avoid this?

If you’re going to automate any parameters in your song - whether it’s VST, native DSPs, or anything else - then it’s always good practise to reset your automations to a default base value at the start of your song. This includes resetting the actual LFO cycle to a starting value as well, by using the LFO reset command x8yy (see the manual for more details). You’re already doing this, so you’re pretty much doing the best thing you can do.

Even if the VSTs get saved with their parameters moved to some different value, it should not matter because they will get reset back to the correct value the next time you play the song from the start. Also, the LFOs have cyclic behaviour, so they will eventually cycle back around to the original value at some point anyway. I don’t believe you should experience any kind of “drift” or other weird side effects that cause your VST presets to be destroyed, or getting further and further away from the original settings.

I use LFOs to control VSTs in pretty much every song I do, and I’ve never experienced a problem where the preset was destructively changed in the way you’re describing.

Thanks for your help :)
I allready do a reset at the top of every pattern, and also have the standard patch value in the automation lane at the beginning of the track.

I think the problem lies in the lfo that works relative to the value in the patch. When i save the patch with a high lfo output value, the next time i open the patch it modulates around the wrongly saved, higher patch value.

I may be wrong as you don’t experience this, but i was sure i heard this in my bass sound where three lfo’s are used over the entire song.

I go check it tommorrow with a special patch to clear this out.

It is true though, the lfo works relative to the patch parameter??

No. The LFO does not try to check the existing value of the parameter it’s linked to and then modulate around that in a relative fashion, it simply sends out an absolute value no matter what.

Perhaps you can mention which plugins you’re using, or provide a demo song that demonstrates any strange behaviour?

Again, thanks for helping!

However, as you describe it seems to me quite logical this happens.
If i have, for example, a patch with filter set at 50% when i load it.
I edit the release in the vst gui and save the patch again.
At the moment i save the patch, the renoise lfo just modulated the filter to 40%.
Now the patch is saved with filter at 40%.
When i load the new patch, the filter gets modulated around 40% instead of 50%.

I watched this happen, but i guess you already understood my initial message, so i’m in doubt if i got something else wrong. I’ll go check it out tomorrow to be sure.

The LFO is always modulating, but you can reset the LFO as dBlue already explained by using the x8yy command where yy is the position of the lfo to continue from.
If you want your VSTI patch to have a filter always start from 50% at the beginning in your song(or any particular position), then adjust the LFO reset parameter by telling the LFO to start modulating at 50% (e.g. 087f as 256/2 = 128 - 1 as 00 is also a value= 0x7f)

That’s the whole trick, the parameter settings should be set by the LFO if you involve an LFO to control it, the saved VSTI parameter will no longer be reliable in those cases.

LFO’s inside plugins makes stuff more complicated though, but those may also be easily set to a specific offset value if the plugin allows you to, but in that case you are always in the merciful hands of the plugin developer.

So, its still not completely clear to me.
I think i understand all things you are telling me, but…
Even though i reset the lfo all the time at the beginning of a pattern, it doesn’t make much difference. The lfo keeps altering the vsti parameter, even when the song is not playing (here in maybe lies a solution, will get back to this at the end of this message).
So when i save the project, in stop mode, it saves the patch as it is. With the filter modulated to 45% instead of the original patches’ 50%. Next time i open the song it loads the patch with 45% as it’s origin. Every time i save and reopen the project, the patch drifts away more and more. When i was doing this today, i used 3 different lfo’s on 3 different parameters of the plugin. So this is quite useless unless i bypass all lfo’s and go to the beginning of the track to let the automation lane do it’s work (where i right clicked the modulated parameters for ‘saving’ in the automation lane). Now the patch is back to the original form, and it’s safe to save. Alternatively i could load the patch every time i open the song. Both way’s are not ideal.
Inless i’m completely wrong, which could be cause i haven’t been in the studio since, a possible solution would be to stop the lfo’s when stopping the song, let the parameter get back to there original position and than save safely.
It could also be that it is a problem with this particular vsti, in which case i’m sorry to have bothered you guys so much. I’ll check this tomorrow as well.

If the LFO did handle everything relatively, then you’re quite correct in saying that songs, presets, etc., would all be ruined very quickly by this, because it would always be drifting away from the center values. This is definitely not the way we want to do things, and definitely not the way that Renoise handles it.

Let’s say that you have an LFO with an Offset of 50% and an Amplitude of 20%. In other words, the LFO is centered around 50% and will oscillate +/- 10% around that center value, from 40% to 60%. The LFO does this absolutely, not relatively. The current value of the target parameter is never taken into consideration by the LFO, and never factored into the calculation of its final output. The LFO does not care about the current value of the target parameter. It will always set the target parameter to a value that is somewhere between 40% and 60%, no matter what.

Now let’s say that you have a VSTi synth loaded in Renoise, and you’re automating its parameters with an Instrument Automation Device. You’ve decided to automate the synth’s filter cutoff frequency, so you have this filter cutoff mapped to a parameter in the Instrument Automation Device, and then you have your LFO connected to this parameter. For the sake of simplicity, let’s say that the LFO’s center point of 50% maps to a filter frequency of 2000 Hz, and the LFO’s amplitude of 20% maps to a range of +/- 1000 Hz, resulting in an LFO that oscillates from 1000 Hz to 3000 Hz.

No matter what you do, or when you decide to save the synth patch, or save your song, or anything else… the LFO will always be outputting its absolute value centered around 50% with an amplitude of 20%. This should always translate to a filter cutoff frequency ranging from 1000 Hz to 3000 Hz, because the LFO is setting this parameter absolutely, not relatively. It’s a totally one-way process: LFO → Instrument Automation Device → VSTi synth. If the LFO happens to output 57%, then it should always translate to a value of exactly 57% in the VSTi synth itself. The VSTi should never suddenly interpret the LFO’s 57% as really being 49%, or 65%, or anything else other than exactly 57%.

If the VSTi synth is somehow treating its parameter changes in a relative fashion, centered around whatever value it started with, then this is totally out of Renoise’s control, and it definitely sounds like buggy behaviour within the synth itself (or perhaps a valid feature that you have unintentionally enabled at some point).

You still did not mention the name of this thing, so that we could test it ourselves. Which plugin is it? :)

So i just tested it, and you guys are right offcourse. I really feel like a donkey right now :(
I should have tested it more before i posted this stuff. It’s just to easy when i have to turn off the studio and then to ask stuff on the forum with my phone when i should wait to double check it myself the next day… I think i made a mistake somewhere when i reassigned one of the parameters and lost the original patch. I now know i have to be careful with this, but it’s not a good thing i took up your time with it. It just show’s the renoise support is really great and i thank you for this!!