In The Design Layer, TLS Productions

Hello everyone!

Due to some scheduling conflicts, the stage & production management entry will be pushed to a later post.

For this post, I would like to share with you a big project I’ve been working on in QLab*.

I have always wanted to be able to project a piano on stage and have the keys light up based on which note is being played or heard on stage.

There have been a few shows in the past where a director has asked for a “ghost piano” or another music based interactive projection and until recently I either did it the very hard way, or told them it just wasn’t possible.

Recently though I had a theatre troupe contact me about a very similar project they’d like to accomplish and I was ready to tell them that they didn’t have the time, or that is just wasn’t possible, until i had a small epiphany.

MIDI Triggers & Record Cue Timing…

If I could meticulously build 88 Video Cues with 88 individual PNG files of each key “lit up” in red, and 88 associated Stop Cues, bundled together in nice Group Cues for Organization…I could use triggers and record any sequence of keys playing back that I want.

That being said, it wasn’t as simple as capturing the MIDI note in the inspector once and then being able to trigger that re key at will.

QLab pays very close attention to velocity, and if I didn’t hit the key with the same velocity each time, the cue would not fire.

Digging into QLab’s trigger settings on their website I found I could use symbols and variables in the velocity box like “<“, “>” & “ANY” to allow for the cue to trigger no matter how hard I hit the keys.

A red key cue would have a velocity of “>1” and the stop cue would be “<1” allowing for it to be lit red for the duration the physical key is held, and stopped as soon as it is released.

Once I built my cue list with all the key video cues and stops, nested in group cues for organization, I created a second cue list to create my recorded cue sequence.

I started the recording process and plucked away at the keys on my midi controller and watched the cues trigger one after the other matching my fingers on the keys.

I clicked stop, and low and behold, the start cues in the sequence played back perfectly.

I’m sure if you wanted to also have GarageBand or Logic recording in the back ground to then create an audio file to go along with the playing, it would be simple enough and allow for a seamless cue on stage to add to the production.

All in all it took just over 264 cues to program the red keys, their stop cues and the group cues they both lived in to get this all functioning properly.

I’m excited to use this in a production someday, if not just utilize it as a learning tool when not only showing the power of QLab, but as a way to show people who may be trying to learn a song or melody and give them a visual of every key as it flies by on the keyboard.

Reach out to me if you’d like the Bundled Workspace to play around with and make your own for your next production or just a fun programming day in QLab!

Please feel free to Contact Dustin D. Miller and send over your questions for next month’s entry, comments on this month’s entry and any and all follows ups on my reviews, tutorials and other content.

Design & Conquer My Friends,


*QLab is a registered trademark of Figure 53, LLC. Dustin D. Miller is not affiliated in any way with Figure 53, he just really likes their software.

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