Automatically speed up audio

[Weaselspoon]

Hello,

I've only given this ten minutes of scratching, but I can't see an easy way to do it, so I ask the brilliant people of this list if anyone has a good method for this.

I've got a short audio sting that fires an indeterminate number of times. What I'd love is if every time it finishes playing it fires a cue that slightly increases the rate, so as the show goes on it gets more frantic, but also burns less time.

It doesn't look from the applescript dictionary that GetRate and SetRate are a thing.

Any ideas of how to do this?

Cheers,

Robert

[Roly Botha]

Rate I believe is get/settable using AppleScript as a property of cues: https://qlab.app/docs/v5/scripting/applescript-dictionary-v5/#cue

You can also use OSC to affect the “live” rate of cues, which I’ve thought about in the past as being like a relative fade, referenced here https://qlab.app/docs/v5/scripting/osc-dictionary-v5/#how-to-read-this-dictionary

Without scripting, depending on how indeterminate the number of times the cue fires is, there’s a world where you have a separate list populated with the audio cue at incrementally faster rates. Off the top of my head a start cue targeting the list would fire the cues in sequence. If that doesn’t work maybe a start cue targeting a “play first and enter into group” would?

Though i suppose manually setting the rates of 10-20 cues may or may not be too time intensive for what you’re after, and for sure isn’t quite as fun as scripting…

Thanks!
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Roly Botha (they/she)

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On 23 Jun 2026, at 15:38, Weaselspoon <wease...@gmail.com> wrote:

Hello,

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[Roly Botha]



[micpool]

Set therate to rate of cue “x”

Set rate of cue “x”  to (therate + 0.1)

[micpool]

If you use a script you will have to reset the playback rate of the cue when you start it. QLab Applescript does not have a live rate property. QLab OSC does.

[Weaselspoon]

Thank you so much, Mic and Roly.

Sorted.

Reminder to self: QLab's documentation is really good if you read it properly, which I very much did not.

Cheers,

Robert

[Weaselspoon]

I've just realised that if I use:

Set rate of cue “x”  to (therate * 1.05946309436)

It'll rise by a semitone every time. Obviously too many decimal places there, but some approximation of 2^(1/12).

Very satisfying.

Robert

[Rich Walsh]

This form is perfectly valid in AppleScript:

set rate of theCue to (rate of theCue) * (2 ^ (1 / 12))

Rich

[Paul]

You could put these OSC messages in two Network cues in a group to increment the rate each time it is run

/cue/5/rate/+ 0.2

/cue/5/start

Put a Start cue in a Cue Cart for unscripted triggering.

Adjust the value 0.2 to suit. You may need a small pre wait (0.1s) on the first cue. You may want to check Preserve Pitch on the audio cue. 

[Rich Walsh]

You realise of course that OSC increments and decrements are arithmetic not geometric? Adding 0.2 to the rate each time is not the same as multiplying it by a fixed ratio.

You can amuse yourself reading about the Weber-Fechner law and how perception is generally logarithmic: the short version of which is that increasing the tempo of something in a linear fashion becomes increasingly less noticeable; accelerandos are generally geometric in nature.

Rich