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Line6 M9 - tremolo going out of sync

Meehaw

Meehaw

Jun 11, 2003
171
1
41
Gdynia, Poland
#1
Hi,

I've encountered a problem with my M9. When I use the opto tremolo or bias tremolo and I manually set the tempo for example for quarter notes in 120bpm and I hit the tap tempo button to resync with the beat/metronome I find that it steadily goes out of sync. This happens with all metronomes (I've checked 3 types). The pattern tremolo and delays seem to sync ok though. Has anyone encountered the same problem? Am I doing something wrong?

:help:
 
#2
Hi. I think this is normal. For something to be synced up in perfect time with a metronome you need to have it connect to a midi word clock of some sort. I've tried using my looping pedal along with a drum machine and have the same problem, it would be fine for the first few seconds and then it would slowly get off time.
 
#4
pedalguy1 said:
Hi. I think this is normal. For something to be synced up in perfect time with a metronome you need to have it connect to a midi word clock of some sort. I've tried using my looping pedal along with a drum machine and have the same problem, it would be fine for the first few seconds and then it would slowly get off time.
Click to expand...

That would be my guess too. It's really hard to get a tap tempo perfectly synced with a precise beat without midi.
 
#5
cheapbasslovin: I've set volsens on zero. Does it still mess up the sync?

pedalguy1 & Jumbotron: I've set the tempo manually to 120bpm - I did not use tap tempo. I only hit tap tempo once to reset the pattern on the beginning of the beat (this doesn't change the bpm count).
 
#6
It's been my experience that a minimum setting doesn't turn it off, just makes it less sensitive. Lower settings actually seem to make the voltage sensitivity more dynamic, I believe because the unit is designed for lower output guitars. When I juice my bass volume and voltage sensitivity I actually get more consistent results from the tremolo. When I play a note it goes right to maximum speed and it doesn't drop from that unless I let it sustain for a really long time. I don't have my unit around right now to test my memory, though.

Good luck.
 
#7
Hi guys,

This is actually a well studied problem. All tremolos with tap tempo will do this to some degree or another, which is one reason why you don't see many tap trems.

It has something to do with how the tremolo is created, as compared to how a digital delay is created.

I'm trying to find the article now so I'll post when I do.

Update:
Ok, I think I found it. A digital delay is not inherently oscillator based(Well all digital circuits are, but the delay creation is not). It is essentially register moving with a very sharp decay. Thus, if the tempo is off slightly, it won't matter, it disappears quickly and then the delay starts again. All tremolos, analog and digital, are based around a low frequency oscillator. This oscillator is always running, and if it is off even slightly, the small error compounds through each cycle and grows slightly out of sync.

Either run it via a midi clock(if the band uses a click) or every once and a while retap the trem.

Hope this helps
 
#9
Don't know exactly what the pattern tremolo is. If it is what I'm thinking, the oscillator may be based on a pseudo random number generator. It may use a sample and hold, which behaves quite a bit differently than the oscillator based tremolo.

I cant be certain unless I saw the code, but that is how I'd do it.
 
#10
The pattern trem is based on the goatkeeper, but with a little less control. It has four time sections, divided equally. Within each time section you assign a number of tremolo cycles from 1 to 16. So the pattern could go '4 cycles' '2 cycles' '1 cycles' '12 cycles' and then would restart.

I would think if it was just a problem of being slightly out of sync that it would affect the pattern trem, and when I've tried looping that has been the case. If I understand the OP right, he is able to sync the pattern trem using bpm.
 
#11
Interesting. I'm not sure than. My only guess is there is a round off error within the programming that compiles. When programs are written in the digital domain, they are often written in what is called fixed point architectures. Easier to process, but some numbers(quite a few actually) can not be actually reached, only get very close. If not careful, these round off errors can cause unexpected results with the program over time.

I'm not entirely sure whats going on unless I saw Line 6's programming.:)
 

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