Film-Tech Forum ARCHIVE: IMAX Point Source DSP w/Center Height

This is topic IMAX Point Source DSP w/Center Height in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Andrew Carr (Member # 9264) on 12-20-2018, 11:42 AM:

Question about giant screen audio...

I was asked about a refurb project we are looking at.
Theater currently has a 6.1 system, basically 5.1 with a center height channel. Custom film being produced for this system.

Just curious if anyone knows of an audio DSP unit that would be recommended for this setup. Specifically when it comes to the eq and calibration of the speakers with the Center Height involved.

Personally, I've only had hands on experience with JSD's and Ovations so I thought I'd ask here before trying to send an Lsr channel to the Center Height speaker, which may just be the answer...

Posted by Mark Gulbrandsen (Member # 72) on 12-20-2018, 11:55 AM:

I have done a number of Giant Screen Iwerks cinemas that had the high center channel and I used my R-2 to do it. We kept the same configuration when we converted those sites to digital some years back. Today you'd use a D-2 to do the same task. The D-2 does an average response using 4 calibrated mics that also takes into account the room itself. You would get very good results. I have used them in hundreds of cinema setups and always got consistently good results.

https://www.acoustx.us/D2_Acoustical_Measurement_System.html

Posted by Sean McKinnon (Member # 612) on 12-21-2018, 11:41 AM:

I assume this is for a digital system? I am partial to QSC and Q-Sys. You did not indicate how you would be getting the audio to the DSP but if you are using a traditional 16 channel AES output from an IMB/IMS or server then either a core 510c with an AES input card or a core 110c and an DCIO provide the inputs you would need. If you are using QSC Dataport amplifiers you could use the 510c (or a I/O Frame) with dataport cards to keep everything nice and tidy on dataports. If its a completely new system I like the DPA-Q series network amplifiers though the S/N ration is not as good as the DCA series however I cannot really say I have noticed it outside of a direct A/B comparison.

Software wise you can program routing easily and graphically and make as many formats, presets, or "Snapshots" as you wish. You could have a snapshot for traditional 5.1, 5.1 with center height, PA, L/R Stereo etc... the sky is really the limit.

I have started using Q-Sys as my DSP and control system in my multipurpose and performing arts center installs including their conferencing and camera options. I use the Q-Sys to do everything from house light control, and masking control, to video control, and more. They are also releasing a Q-Sys compatible version of their IMS next year which should make it a snap to integrate server control. They also support Dante and other digital audio networking platforms which I find quite handy.

As you can tell I am a fan! You can use q Q-Sys core and DCIO as a complete standalone system or you can pair it with a cp850, trinnov, or AP-20/25. I have recently done a Q-Sys system with a cp-650 for optical film, SR*D, and 70mm Mag including outboard noise reduction frames and an MPU. The Q-Sys handles all of the routing, switching, and logic.

So to sum it all up if I was looking for a DSP platform to build a custom cinema sound format on I would hands down pick Q-Sys. My second would be Symetrix (which we used a lot before Q-Sys) but at this point its a very very distant second.

Posted by Steve Guttag (Member # 268) on 12-21-2018, 05:40 PM:

I'm also a QSYS fan. It really is up to one's imagination as to what you want to do with it. We aren't doing any video with it but some control and definitely audio.

Sean, how's your LUA scripting coming? [Big Grin]

Posted by Sean McKinnon (Member # 612) on 12-21-2018, 08:26 PM:

Steve, I am really just beginning with LUA. So far I have been able to do everything I've needed with logic components, command buttons, and the block controller it's not the most elegant or most efficient but it works. Once I get off the road and back in the shop I'll send you some examples.

I want to clarify that q-says doesn't handle video yet per say but they can control video and offer a bridge for streaming. I use crestron DM matrices for video and use the q-sys to control the routing.