Mic cues & processing

[Roly Botha]

Hey all

Working on a show which requires some light vocal processing of a handheld microphone (filters, delay, reverb, etc) which I’ve previously been running via ableton, controlled via MIDI from QLab. 

We’re taking the show to Edinburgh and looks like Ableton won’t be an option as we’ll be using the house machine for playback and it’s fairly unlikely we’ll be able to take a separate machine ourselves. 

Just wondering how folks have found using AUs on mic cues? I recall trying a few years ago and the latency being enough of a problem that I’ve steered clear ever since. Is this expected or do people usually find no issues?

Thanks!

All my best,

Roly (they/them)

--

Roly Botha

Actor and Composer

www.spotlight.com/9738-1272-3687 

www.rolybotha.co.uk

As a freelancer, I will sometimes send emails at unusual times. I never expect anyone to respond outside their own normal working hours.

[micpool]

I think, if my show was heavily reliant on live processing of sound, or was in any way complex, I would take my own computer to use in Edinburgh. There are so many problems that can crop up with shared QLab computers in the anarchy and mayhem of a smaller fringe venue that are best avoided. 

Having said that, if you are setting up your own machine, or decide to try and successfully negotiate installing your show on a venue computer, you still need to understand a few basic things 

The common myth is that QLab has more latency than other software, e.g., Mainstage or Ableton.

Out of the box, that is the case because the default buffer size in QLab  is set to 512 samples in and out (1024 round trip), and in Mainstage it is 128 (256 round trip)

QLab defaults to a higher buffer for a practical reason - to accommodate the frequent need for it to play numerous audio tracks asynchronously. These tracks may have different starting times, mismatched audio formats, and require the processing of scripts, high-bandwidth asynchronous video content, and various other CPU-intensive tasks.

If your playback requirements are simpler you may well be able to use a smaller buffer size. Here is a table of buffer sizes vs latency at 48K. However if you set the buffer too small your audio can rapidly become unreliable and sound dreadful.

In QLab Buffer size is set in QLab preferences (not settings) hardware

This is another area, like not imposing any limits on the number of simultaneous audio tracks you can attempt to play back, where it is up to the user to determine the capabilities of any particular QLab /mac configuration , through thorough testing.

In your case, where you are going to be using a QLab computer in a venue that will host performances by many different companies every day, there is potentially a real danger of messing up someone else's show, if you were to set a lower buffer size, particularly as there may be a huge variation in technical knowledge across all users of the sound system, and you probably don't want to be the person responsible for causing this, or worse having people with limited technical knowledge spending hours trying to track down why their show, that ran perfectly yesterday, is now glitchy, because I can almost guarantee that if they don't know about the buffer sizes in preferences now, they won't when they are in a blind panic in a twenty minute turn around between shows.

There is a technique which, in theory, enables small buffers for microphone cues while still allowing large buffers for audio playback. I have tested this reasonably thoroughly in the studio, but again I urge caution, as I haven't used it on a major show, or in a multi-company venue.

If you look at my audio device list you will see that as well as an Octacapture there is also an Octacapture aggregate. This is quite simply an aggregate device, created in Audio MIDI setup which just uses a single device.

This may work for you

Beyond this, I would stick to the simplest AU Plug-ins available. (The current Apple AU's installed on every Mac are eminently useable) this gets around the problem of installing and authorising complex plugins on a shared computer,

You may find some useful information about plug-ins here, although it is somewhat out of date, particularly in relation to AU's in QLab 5.

https://qlab.app/cookbook/a-plug-in-primer

Good Luck!

Mic

[Roly Botha]

Thank you Mic for, as always, coming through with the most comprehensive and helpful advice. 

Really useful - thanks so much!

All my best,

Roly (they/them)

--

Roly Botha

Actor and Composer

www.spotlight.com/9738-1272-3687 

www.rolybotha.co.uk

As a freelancer, I will sometimes send emails at unusual times. I never expect anyone to respond outside their own normal working hours.

On 11 Jul 2023, at 12:08, micpool <m...@micpool.com> wrote:

I think, if my show was heavily reliant on live processing of sound, or was in any way complex, I would take my own computer to use in Edinburgh. There are so many problems that can crop up with shared QLab computers in the anarchy and mayhem of a smaller fringe venue that are best avoided. 

Having said that, if you are setting up your own machine, or decide to try and successfully negotiate installing your show on a venue computer, you still need to understand a few basic things 

The common myth is that QLab has more latency than other software, e.g., Mainstage or Ableton.

Out of the box, that is the case because the default buffer size in QLab  is set to 512 samples in and out (1024 round trip), and in Mainstage it is 128 (256 round trip)

QLab defaults to a higher buffer for a practical reason - to accommodate the frequent need for it to play numerous audio tracks asynchronously. These tracks may have different starting times, mismatched audio formats, and require the processing of scripts, high-bandwidth asynchronous video content, and various other CPU-intensive tasks.

If your playback requirements are simpler you may well be able to use a smaller buffer size. Here is a table of buffer sizes vs latency at 48K. However if you set the buffer too small your audio can rapidly become unreliable and sound dreadful.

<Screenshot 2023-07-11 at 11.05.36.png>

In QLab Buffer size is set in QLab preferences (not settings) hardware

<Screenshot 2023-07-11 at 11.24.03.png>

This is another area, like not imposing any limits on the number of simultaneous audio tracks you can attempt to play back, where it is up to the user to determine the capabilities of any particular QLab /mac configuration , through thorough testing.

In your case, where you are going to be using a QLab computer in a venue that will host performances by many different companies every day, there is potentially a real danger of messing up someone else's show, if you were to set a lower buffer size, particularly as there may be a huge variation in technical knowledge across all users of the sound system, and you probably don't want to be the person responsible for causing this, or worse having people with limited technical knowledge spending hours trying to track down why their show, that ran perfectly yesterday, is now glitchy, because I can almost guarantee that if they don't know about the buffer sizes in preferences now, they won't when they are in a blind panic in a twenty minute turn around between shows.

There is a technique which, in theory, enables small buffers for microphone cues while still allowing large buffers for audio playback. I have tested this reasonably thoroughly in the studio, but again I urge caution, as I haven't used it on a major show, or in a multi-company venue.

If you look at my audio device list you will see that as well as an Octacapture there is also an Octacapture aggregate. This is quite simply an aggregate device, created in Audio MIDI setup which just uses a single device.

<Screenshot 2023-07-11 at 11.46.13.png>

This may work for you

Beyond this, I would stick to the simplest AU Plug-ins available. (The current Apple AU's installed on every Mac are eminently useable) this gets around the problem of installing and authorising complex plugins on a shared computer,

You may find some useful information about plug-ins here, although it is somewhat out of date, particularly in relation to AU's in QLab 5.

https://qlab.app/cookbook/a-plug-in-primer

Good Luck!

Mic

On Tuesday, July 11, 2023 at 9:53:28 AM UTC+1 Roly Botha wrote:

Hey all

Working on a show which requires some light vocal processing of a handheld microphone (filters, delay, reverb, etc) which I’ve previously been running via ableton, controlled via MIDI from QLab. 

We’re taking the show to Edinburgh and looks like Ableton won’t be an option as we’ll be using the house machine for playback and it’s fairly unlikely we’ll be able to take a separate machine ourselves. 

Just wondering how folks have found using AUs on mic cues? I recall trying a few years ago and the latency being enough of a problem that I’ve steered clear ever since. Is this expected or do people usually find no issues?

Thanks!

All my best,

Roly (they/them)

--

Roly Botha

Actor and Composer

www.spotlight.com/9738-1272-3687 

www.rolybotha.co.uk

As a freelancer, I will sometimes send emails at unusual times. I never expect anyone to respond outside their own normal working hours.

--
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