Mic Cue Latency (8 inputs)

[Nick Williams]

Hi All,

This is my first post here...

I'm working on a small scale musical at the moment. I have a soundcard with 8 inputs (Behringer Ultragain Pro 8). If I create a qlab file in which I programme mic cues on/off with wet/dry FX for all eight inputs (all microphones), will I encounter latency issues? I see back in 2013 there was discussion on this forum regarding mic-latency, have these issues been resolved. I'm running Qlab version 3.1.13 (but notes on other version regarding latency are also welcome).

Latency is a big problem given that the performers need to keep in time with one another so this is a deal-breaker for me whether or not I use Qlab for my mic cues.

Many thanks for all of your help, in advance. 

Cheers,

Nick

[Chris Ashworth]

Nick,

Welcome to the list! 

The latency mentioned on this list from very early versions of QLab 3 was resolved.

If you add effects you will add latency. 

I’d recommend trying it out and seeing how it goes.  You can enable demo mode via “QLab” —> “Start Demo Mode…”

Others on the list will probably have deeper wisdom on the subject, but that’s a start.

-C

[Nick Williams]

Thanks Chris,

I already own 3.1.13 so I have that going for me! 

When I plug one mic in at home via my MOTU soundcard (i.e. not the soundcard I will be using next week) I get no noticable latency even when applying EQ and delay to the input through Qlab. So I guess I'm wondering if running more mics, creating more cues, and applying more effects to those extra inputs will increase the likelihood of/or overall latency OR if there's no latency now there won't be any more later?

You may have already guessed but I'm wondering whether to invest the time now in creating all my mic cues in Qlab (something I had a digital desk doing last time out) or if that would be a waste of time as I'll just experience issues when I get to run it with all the mics next week. I don't have the mics/soundcard I will be using until next week (day of the show, gulp).

Thoughts welcome!

Nick

[Chris Ashworth]

Hi Nick,

Ah, makes sense.

Creating more cues or running more mics through the same physical device won’t add latency. It’ll add processing requirements, so you could hit dropouts if you’re hitting the limits of the machine, but it won’t add latency.

The device will be a factor in the final latency; for example the buffer size it is using. 

In terms of prepping for the day of the show, that gets outside my area of expertise a bit, and others on the list will have better answers.  Many folks prefer to use a dedicated desk if they have it, since there are advantages to having physical faders you can use, among other things.  But depending on your needs it may make sense to set up mic cues in QLab to have them available if you want them.

-C

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[Nick Williams]

Thanks again, Chris.

Yes, two weeks ago all my mic cues were sequenced on a Yamaha LS9 digital desk, easy-peezy one button to nudge to the next mix. Last night I programmed 50 Mute Groups on an old Allen and Heath analogue GL4000, had to ride the faders throughout the show but my mic ons/offs were all there (had to compromise a little on the FX). Next week though I have to hand the show over to VERY inexperienced operators (first-timers) so, ideally, am aiming to make the sound cues and mic cues all merge into one beautifully crafted Qlab file so they just have to press space at the correct time and they're golden. Just that niggly feeling that the whole system will collapse once it's up and running and I'll have wasted a day or two programming mic cues. Feeling a little more confident after your response, let's see what else comes into this thread...

Anyone else have reassuring opinions (or not so reassuring opinions)??

Nick

[micpool]

Microphone cues are great for the odd mic cue in a play, but I don't really think you can mix a musical with them with no additional hardware. And if you have additional hardware then you might as well have a digital desk.

The other thing about Microphone cues is that the latency you get will depend on the buffer settings of your interface in QLab preferences on the Qlab menu (not settings on the gear icon) 

By default this is 512 which gives you a round trip latency of somewhere around 40ms, which is OK to a bit on the long side.

If you are only using a few simple sound cues with the microphones you may be able to reduce the buffer to 256 to give you  around 22ms or even 128 for 14ms if you have a powerful mac. But you will get dropouts if you play anything that taxes the CPU like video or complex sound sequences or effects.

One other possibility is running MainStage on the same Mac as Qlab which can give you a more easily accessible interface which you can control on the IAC bus from QLab using MIDI Program changes and control changes. 

If you only have an analogue board and you want to add mute automation using Qlab then you could patch the Analogue channel inserts in and out on your  QLab interface

But unless you have to, or you enjoy having a miserable time, get  a proper desk.

Mic

[Daniel Perelstein]

Are you back on an ls9 with the inexperienced ops, or still on the GL4000?

I don't have anything to offer re programming a musical using qlabs mic cues (except to say that it isn't standard yet in the biz, from what I can tell from my vantage point)... BUT, based on what you've written here, it seems like you may be able to meet your goals regardless.

If you're on a desk that can automate the parameters you need, and responds to midi, it's quite easy to program your playback cues and a series of midi cues recalling console presets integrated into the same sort of cue list you're envisioning.

That said, on the gl4000, it won't keep your ops from having to do the work you're trying to avoid asking of them. Your ls9 would do fine though.

Sorry that that's off topic from your ACTUAL question.

Dan

[Nick Williams]

Thanks Dan, 

Nope, the LS9 and GL4000 are now history, the show will go to Edinburgh for a run on a MixWizard (10ins, no MIDI as far as I can tell). I'm gutted as the venue had to choose between a digital or analogue desk, they chose the analogue and my design went up in smoke!

So, I'm trying to simplify or find a workaround.

Cheers for the input,

Nick

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[Rich Walsh]

Don't forget that the latency is also a function of the sample rate.

Does the Behringer have an internal virtual mixer? You could do a fairly good job of turning channels on and off with very little latency by MIDI controlling RME's TotalMix, for example: the audio doesn't need to get to the computer and back.

Rich

[Jevans]

An A&H MixWizard is a totally different league of desk to an LS9 or GL4000 (in the wrong direction - not that there's anything wrong with it for what it is); given that it's a small analogue mini mixer it's not possible to mix a musical in the same way as on a full VCA console. With only 8 mics and inexperienced ops I'd say just board mix it without the VCA cues.

I've put my VCA recalls and QLab cues on a single stack before (QLab wasn't in control of the VCAs, it just fired the desk scenes via MSC) and I never did it again. I found it was just too annoying in tech and easy to make a mistake - if an inexperienced op panicked and either double fires or misfires a cuestack it's one thing; it's even worse if they can stuff up the board and play extraneous playbacks at the same time. I'd also say that in the average fringe venue they're not going to have enough time to make sure this works every time unless you're touring your own kit - and if you're doing that you could pick your console! I'd keep it simple - better to have dull unexciting sound where everything's audible than be ambitious and fail.

YMMV, just my tuppence.

Thanks,

John