Devamp Cues

[Alastair Gavin]

Hello

Could someone kindly offer me some advice on setting up devamp cues?

The attached screen grab shows my attempt to loop two elements of the 'Gloria 1' group: 'Gloria 1 click' (sent just to the musicians) and 'Gloria 1 mambo cowbell' (sent to the FOH desk) - I wanted this to vamp til ready and then within any point in the 2 bar loop to trigger the devamp cues to run to the end of the loops and then to immediately enter the next group 'Gloria 2'.

The looping is working fine but I cannot get the loops to devamp without a small delay in the click - post wait times would then appear in that column even though I set them to zero. I first tried with just one devamp cue which would leave the cowbell loop running and still glitch into the click, alternatively with two devamp cues I couldn't make a smooth transition into the next group. All the next group targets start dead on the beat so there shouldn't be any delay.

If my setup doesn't make any sense, alternatively can anyone point me to a tutorial for setting up devamps? The PDF documentation is very sketchy on these.

Any help much appreciated. Thank you!

[Chris Ashworth]

Hi Alastair,

On May 8, 2012, at 7:01 AM, Alastair Gavin wrote:
>
> The looping is working fine but I cannot get the loops to devamp without a small delay in the click - post wait times would then appear in that column even though I set them to zero.

The Devamp cues automatically set the post wait time when they are fired. The time matches the amount of time left in the loop on the target cue.

Are the following audio cues set to "guarantee sync"? If so this may be the source of the glitch at the top of the click, as the way QLab is currently designed it must sometimes shave a few samples off the top of the file when guaranteed sync is enabled.

Best,
Chris

[Dave "luckydave" Memory]

Hi Alistair.

It's also worth looking at whether the cue following the devamps is loaded. If not, it's having to load before it can play, which can introduce a little moment of lag. Since the auto-continue and post-wait only show up while the Devamp is working, the cues after Devamp cues don't automatically load. Add a Load cue to the Devamp sequence, targeted at the following cue sequence, and that will set you up for smoother playback.

-- 

luck...@figure53.com

[Chris Bakos]

I have also found that devamping from one group to another does not provide a reliably "musical" playback and often introduces a slight stutter at the "devamp and move to the next group" position for the playhead. It is better to have all of your audio in a single, or set of files that are grouped to "fire at once" and are looped via qlab and simply devamp into themselves (if that makes sence) Like this

Cue A (Fire all children at once group Syncronization ON)

   Track 1a Intro-Track1b loop point - Track 1c continuation after devamp

   Track 2a Intro-Track2b loop point - Track 2c continuation after devamp

Cue B (Fire all children at once)

   Devamp Track 1

   Devamp Track 2

This has alway provided seamless playback for me on all systems

That being said, I would love to see some more in-depth tutorials for the devamp que as I believe it is a very powerful tool that I only partially understand. 

[Alastair Gavin]

Hi Chris

Your method of devamping into the same cue has worked perfectly for a single vamp. Thanks for the valuable assistance!

Any thoughts on how I can set up more than one vamp in a cue? Previous posts in this group have indicated that multiple vamps are not possible but then I think these have been referring to previous versions of QLab and I'm wondering whether in V2 this is now possible. Logically one would have thought it would be possible to set up different cues for different sections in a song but then we're back to the original issue I posted where there's a stutter when you move to the next cues. I thought maybe there'd be a way of setting up vamps within the sections ie not at the end or beginning of cues so that you move from one unlooped section into another unlooped section in the next cue and arrive at the loop later, if that makes sense. We are running click tracks for the band as well as audio for FOH so we do need the transition to be absolutely seamless, and I guess this is where we're stuck at the moment, and being relatively new to QLab I've butted up against my knowledge threshold!

This is for a show in the West End, London so is a serious enquiry in need of a solution!

Thanks again for any suggestions.

Alastair

[Rich Walsh]

On 11 May 2012, at 10:41, Alastair Gavin wrote:

> Any thoughts on how I can set up more than one vamp in a cue? Previous posts in this group have indicated that multiple vamps are not possible but then I think these have been referring to previous versions of QLab and I'm wondering whether in V2 this is now possible. Logically one would have thought it would be possible to set up different cues for different sections in a song but then we're back to the original issue I posted where there's a stutter when you move to the next cues. I thought maybe there'd be a way of setting up vamps within the sections ie not at the end or beginning of cues so that you move from one unlooped section into another unlooped section in the next cue and arrive at the loop later, if that makes sense. We are running click tracks for the band as well as audio for FOH so we do need the transition to be absolutely seamless, and I guess this is where we're stuck at the moment, and being relatively new to QLab I've butted up against my knowledge threshold!
>
> This is for a show in the West End, London so is a serious enquiry in need of a solution!

If the show's an Autograph show, I think should you contact Tim Middleton and get his help – he's one of the best QLab programmers who's passed through the NT in the last few years…

You can't set multiple loops in QLab (at present), and although you could adjust them on the fly with scripts the audio drops out briefly whenever you change one of the cue times. However, I've just done a quick test and it is possible to get QLab to move seamlessly between a sequence of separate looping cues via devamp, provided each cue is loaded before it is fired and guaranteed sync is turned off. For a single transition, a Devamp Cue does exactly what you want (ie: come out of a loop and move to a coda – or another looping cue) if you pre-load the next cue and don't have guaranteed sync on. You can them extrapolate from that to construct any sequence you want.

If the sequence you're trying to achieve is very complicated though, you may be better off using Ableton Live in the background to deliver the musical content – particularly if you're also working with multiple stems.

Are you sure the stutters aren't due to the editing of the audio files? Do they transition cleanly when laid out end-to-end in a DAW? Is the click interleaved into a single multi-channel file with the FOH part? This would help a lot, and simplify the programming. Looking at your screenshot, I guess not – and trying to deliver 13+ audio files simultaneously in sync is going to require a certain amount of optimisation off your machine. You might like to take Skype and Dropbox offline for a start – and install those 2 updates from Adobe and not expect QLab to deliver stutter-free audio while iSync is syncing!

Rich

[Alastair Gavin]

Thank you very much Rich, kind of you to supply such a detailed response. I will pass this on to our sound guys.

My audio files are edited on the nose so do transition cleanly in my DAW but also appreciate that my laptop shouldn't be trying to achieve other stuff in the background! I have been mainly working at home to research the possibilities in QLab. On a recent tryout gig everything else was certainly turned off, but a main factor I'm sure will be my rudimentary knowledge of the software...

Reassuring though that you are confident that we should be able pass seamlessly between looping cues.

Kind regards,

Alastair

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[Chris Ashworth]

One more idea to add to Rich's excellent advice:

If you really have trouble getting a clean transition between two files, you could always do a brief crossfade between two clips to help ensure no glitches. (Give the second cue a small amount of time to get up and running, then cross fade the two.)

As Rich noted, constructing multiple devamp sequences is on the list for improvement, since the above technique can get especially unwieldy in terms of number of cues.

-Chris

[Chris Bakos]

"As Rich noted, constructing multiple devamp sequences is on the list for improvement, since the above technique can get especially unwieldy in terms of number of cues. "

Or even multiple loop points within a single file/effect would be desired. I often find I have a song that has 2 or 3 viable loop points that would work as vamps, but since the current build only allows a single loop point, I cannot do that. To get around this, I will often run 2 or 3 files side by side, each with it's own different loop point,  fired all at once(with synchronization)  with the crossfade trick. It can work but often still reveals the crossfade a little. Maybe not enough for anyone but me to notice, but I still hear it every time. 

[Chris Ashworth]

On May 11, 2012, at 1:36 PM, Chris Bakos wrote:

> "As Rich noted, constructing multiple devamp sequences is on the list for improvement, since the above technique can get especially unwieldy in terms of number of cues. "
>
> Or even multiple loop points within a single file/effect would be desired.

Stay tuned. :-)

-C

[Jeremy Lee]

All of this is very possible, but the more complex the vamp iterations are, the more complex and situation specific the programming becomes.  But, no, QLab doesn't allow you to simply change the loop times on a cue in the middle of a show or to have multiple loop points in a single cue.  You just have to set it up in a way that works with its logic.

This doesn't mean that you have to do all of the editing externally- you can use the Start, Stop and Loop points in different iterations easily.  Just make sure that all of your loop points are totally clean.  And be smart about pre-loading cues as well as the vamp/ devamp.  Never use Guaranteed Sync.

On 11 May 2012, at 10:41, Alastair Gavin wrote:

Any thoughts on how I can set up more than one vamp in a cue? Previous posts in this group have indicated that multiple vamps are not possible but then I think these have been referring to previous versions of QLab and I'm wondering whether in V2 this is now possible. Logically one would have thought it would be possible to set up different cues for different sections in a song but then we're back to the original issue I posted where there's a stutter when you move to the next cues. I thought maybe there'd be a way of setting up vamps within the sections ie not at the end or beginning of cues so that you move from one unlooped section into another unlooped section in the next cue and arrive at the loop later, if that makes sense. We are running click tracks for the band as well as audio for FOH so we do need the transition to be absolutely seamless, and I guess this is where we're stuck at the moment, and being relatively new to QLab I've butted up against my knowledge threshold!

This is for a show in the West End, London so is a serious enquiry in need of a solution!

-- 

Jeremy Lee

    Sound Designer, NYC - USA 829

        http://www.jjlee.com