Virtual faders don't keep up with fast Fader Controller movements

G

geneticfunk

New member
When I control virtual faders using my BCF2000, the virtual faders don't keep up with fast Fader Controller movements. If the Controller fader movements are fast enough, sometimes most of the movement is missed by the virtual faders. This seems to have something do with Nyquist's sampling frequency rule, for those who know what that is about.

I've talked to various people about this, and I've heard that it could also have do with the smoothing between MIDI values that occurs in the BCF, similar to the "Smoother" modules in Reaktor.

I've tested other Control Surface faders, and some of them seem to keep up with the virtual faders better than with the BCF, but I've never seen both control surfaces run on the same system so it's tough to compare with any sort of certainty. However, even this more responsive behavior that I've observed on certain setups leaves a lot to be desired.


I was at the point of saying "maybe technology just isn't able to do this at this point in time," but then I saw an incontrovertible counterproof to this notion. That counterproof is: If you use the mouse to click on a control knob in Reaktor, and then move the mouse up and down in a very fast and complicated pattern, the knob's movements follow the mouse's movements perfectly.

So, the technology is out there to accomplish what I'm talking about. It just seems like none of the big brilliant companies out there have chosen to implement it yet... or more likely that they can make more profit by not implementing it at this point in time.

Many people say with some sort of disdain, "ooh, why would you want to move the fader fast, that's stupid," but I think that these people lack imagination. Fast fader movements can make for amazing control patterns and live performance possibilities. Anyone who has seen scratch dj's like Qbert or Dstyles knows better... and what Qbert and Dstyles do only scratches the surface of what responsive fader based control is capable of.

Any thoughts, insights?
 
I suspect what is happening is a screen redraw issue, not an audio issue. You describe the faders visually but not how they are functioning as far as the audio itself. Of course, the audio is really all that matters.

The DAW I use prioritizes audio ahead of screen redraws, so if there's a lot of data you might see jerkiness on the screen or redraws get behind, much as you describe. However, I've never had it happen that the audio itself was affected negatively.

I don't see how this screen redraw issue has anything to do with the Nyquist theory. Perhaps the midi data gets backed up a little, but if you are hearing audio and there are no glitches, then the lagging faders have absolutely nothing to do with Nyquist or anything else in the signal path.
 
geneticfunk said:
Nyquist's sampling frequency rule, for those who know what that is about.

Any thoughts, insights?
Click to expand...
I've got both a thought AND an insight.

The insight is that you should keep your precious, pretentious twaddle to yourself and not bother us with it.

The thought is that Sonic Albert has already set you straight regarding your clumsy involking of 'Nyquists sampling frequency rule' in a context in which it does not apply.

But just in case you misunderstood let me make it perfectly clear --- you can pretend to know more than you do in front of your significant other and your non-technicial buddies, but when you try to bullshit a group of various audio professionals who are donating their time to help people of all ages and experience levels get a grip on what they need to do to get started with or improve their home recording skills you'll get called on it every time.

I rarely do this, but I'm going to dock your reputation for this --- it's THAT serious in my eyes.


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Thanks for the response sonicalbert. The audio wasn't keeping up with the controller fader's movements either.

I wasn't thinking about the audio sampling frequency in relation to Nyquist, I was thinking about the fader position sampling frequency. Nyquist applies to any sort of sampling frequency, not just audio sampling frequency. Believe me, I know Nyquist, I was a Chem major and math minor, and I almost have a physics minor.

I wasn't trying to be pretentious by saying "for those that know," I was trying to encourage people who don't know Nyquist but who may still have useful information related to the problem to not be turned away from responding by my mentioning of something foreign. I can understand how it could be misunderstood, internet forums tend to be a hotbed of pretentiousness.

But I figured out why I'm having the problem. The BCF2000's faders (and all other motorized faders that I've tried) simply aren't made to handle fast fader movements. If I use a nonmotorized fader, the audio and the screen image keep up with my controller fader's movements fine.
 
The audio was probably keeping up with the fader movements, but the faders moves were probably slow due to the BCF2000. The audio didn't know you wanted it to change faster, it only responded to what it saw from the BCF.

Same actually would hold true of the screen redraws. What you saw on the screen was in response to input from the BCF. Since it keeps up with the faster non-motorized fader, then the CPU/DAW is not the culprit.

It appears from your post that the BCF2000 is the cause of the slow fader response. My understanding at this point is that you would move the faders quickly on the BCF, but the slowness in response was within the BCF or on the BCF midi outputs, not further down the chain.

Midi lag is another explanation. If there was a lot of midi data going down the pipe, that could get backed up and cause those kinds of lags.
 
This has nothing to do with Nyquist at all. What it has to do with is cheap implementation of motorized faders. This is very common until you get into things like Uptown Automation and Neve Flying Faders. Then again, those are WAY more expensive than anything Behringer, and given the BCF2000's price point I think it easily outperforms its cost, even if it is extremely unintuitive and a royal pain to program.
 
But you have to question its value if it doesn't track moves well. That's what mixing is all about. Apparently the problem is obvious with fast moves, but it would still be there on medium speed moves and slow moves, just less apparent to the operator.
 
SonicAlbert said:
The audio was probably keeping up with the fader movements, but the faders moves were probably slow due to the BCF2000. The audio didn't know you wanted it to change faster, it only responded to what it saw from the BCF.
Click to expand...

Yep, this is what was happening.
 
I had one briefly and no problems like the ones mentioned here, but I never tried any lightning fast fades either. Once I finally got the stupid thing up and working properly it did what it was supposed to, just wasn't very nice. On the other hand, the Yamaha 01V96 that I just picked up works INCREDIBLY well with Cubase at least. MUCH better than any of the other controllers I have seen.
 
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