The Qlab Machine

As I was saying recently I was working on an amateur production of Footloose for dBS Solutions. The director at the eleventh hour decided to scrap the live band and go with a multi tracked band recording and playback solution (I won’t be into the MU ethics of this!). But in order for this to playback and work correctly we needed an audio playback system which could playback at least 16 channels of audio and more importantly have good redundancy. We turned to what we know and love best… Qlab.

We currently use Qlab for sound effects, stereo playback, basic video and MIDI routing and triggering. However we now had to up the ante. The plan was to develop a Qlab system to playback both the Multi-track band, Sound Effects and handle the MIDI routing. To do this we would need a dual mac machine, that would allow instant switch-over of at least 16 Channels of Audio and MIDI In and Out.

We began to look at several options. For the audio our original idea was to go the Dante card route. Something I talked about in my post from PLASA earlier this year. This system allows you to have 16 Channels of Audio sent out of a computer on cat5 straight into a Yamaha Desk (In this case an LS9-32). This system has a driver that installs on the system, and means the mac or PC see’s the Cat5 as a 16 I/O soundcard. Combine that with a network switch and another backup machine, you have a switchable dual 16 Channel system. Based around 2 Macbooks and the MIDI Solutions Switching equipment we had already. However due the fact the driver requires licensing on every use making using different machines difficult, we decided spending money on Dante as a solution wasn’t the best investment or solution for this problem.

So Chris found and got in touch with a company called Cue One. Who specialise in making playback machines. Originally based around SFX machines, but now they do Qlab machines! They had designed a system based around 2 Mac Mini’s with there own switching hardware, 2 KVM switchers and an ADAT Switcher. The system allows for a one button switch over of up to 32 Channels of Audio, MIDI I/O and 2 Video Outputs. While much more expensive as a solution, it offered a complete and tested solution in a very tidy package. So we decided to go with it!! 2 mac mini’s (With dual video outputs) were bought, the switching equipment from Cue One and a great flightcase from the nice guys at Blacka.

To get the audio out of the mac’s we bought 2 Presonus Firestudio Lightpipe. Which gives you 32 channels of ADAT out via Firewire. A great product! A few issues… Firstly was the fact our new Macs had Firewire 800 no 400, buying 2 new cables solved that! Next problem was that our new macs ran Snow Leopard, and there were issues with the supplied driver. A new BETA driver from Presonus however solved the issues. (More information here). We then following advice from Cue One went for an external clock to provide wordclock for the system. After some tweaking with the audio devices settings in Audio MIDI Settings, we were able to get the Presonus interfaces to clock to the external input. Once we got this working, they clocked to the external source quickly upon receiving power. Wordclock is also delivered to the LS9, with the availability to clock external pre amps as well (We often use Focusrite Octopre’s for Radio Mics).

For power we went for a UPS system to assure a good power supply to the whole system. We decided to power both macs, interfaces and the main switching systems off the UPS. The other options were to power the backup mac off the mains directly, so that if the UPS fails, a mac is still operating. But due to the switching equipment then failing we decided to go for all essential equipment on the UPS.

The result is a system which we have tested to run up to 20 simultaneous audio channels from the mac mini’s (Sub mixed in Qlab to 16 Outputs). But I thoroughly believe the system (maybe with the introduction of firewire hard drives) could handle 40 channels or maybe more submixed to the 32 outputs of the system. While we never had to switch to the backup machine during a show we tested the switching process and it was brilliant. A small blip in audio but you were straight back! Just what you need. The remote control worked really well, although i’d like to see a new design for the switchover button (where awaiting delivery of V2 of the Cue One switcher).

One of the best features of Qlab is it’s Devamp cues, which allow you to loop a section of the track until you tell the system to then carry on. This allowed the MD of the show to accurately recreate the score, and for spoken sections of the show where there were dialogue in-between singing, it made the whole show flow alot better and sound just like a real band reacting live. This was possible though due to us using multi channel waves, developed for us in film for the now multiple channel outputs (over stereo), its effectively just incorporating many mono files under one container file. We used Audacity to create the files (more information here). Audacity was great as it allowed easy matrixing of the files (which originated from Pro Tools). The only problem with multi channel waves were the time taken to create, bouncing stem mixes out of Pro Tools took time and if you wanted to make a change to one channel you had to recreate the entire multi channel file. The bonus however is that you had a tidy qlab file, make for easy file management and the use of the devamp and fade cues.

Overall though the system was fantastic, and didn’t fault during the entire run, which considering I had to finish building and preping it on site, was a great feat! There are some pictures below of it during construction and briefly the finished product. We are swaping some of the parts of it as they are demo parts from Cue One, and the Mac Mini’s are being rackmounted but otherwise the pictures show the completed system.

If your interested in more information about the system, how Qlab can work for you, or in hiring the system please get in touch!

Links
dBS Solutions
Cue One
Qlab
Audacity
Presonus
Blacka

Photos