|
Setting up for Surround
Have you been out to the movies recently, maybe to see one of this summer’s latest blockbusters? If you have, you must have noticed the incredible surround sound complimenting the cutting edge CG visuals. A long time standard in the audio post-production industry, surround sound mixing and Pro Tools have been synonymous for nearly a decade. In the spirit of all things Hollywood, this week at the Pro Tools Corner I want to show you how to set up your system for a basic surround workflow. In the first half of this two-part article, I will breakdown the basic hardware required for a surround mixing setup and introduce you to a cool plug-in that helps Pro Tools LE/M-powered users mix in surround.
Getting Started: Surround Hardware Requirements
Interface:
First things first, to mix in surround you are going to need an interface that supports more than 2 analog audio outputs (sorry Mbox users). In fact, if you want to mix in the most common surround format (5.1), you will need at least 6 discrete outputs, one for each of the 5 satellite speakers and 1 for the subwoofer or “LFE” channel. The following Pro Tools compatible interfaces will provide enough analog outputs for a proper 5.1 mixing setup:
Digidesign interfaces: 002, 003 (rack or CS versions), and Mbox 2 Pro.
M-audio interfaces: Firewire 410, Pro Fire 2626, Fast Track Ultra Series, Delta 66 and Delta 1010.
While the Digi 001 would technically work, it is not supported with Pro Tools 7, which makes it incompatible with the Mix51 plug-in I’m about to show you. Most Pro Tools HD interfaces support at least 8 outs, and I am sure if you own one you know its IO capabilities.
Surround Monitoring:
Of course for surround sound monitoring you are going to need more than 2 speakers. Forget about using a cheap consumer “home theater in a box” setup, as most of these amp/speaker combos are designed to accept only pre-encoded digital streams of Dolby or DTS (we’ll cover these formats next week) and unless they have a way of accessing the discrete analog inputs of each channel, they aren’t going to cut it. Fortunately there are dozens of affordable satellite + subwoofer options available these days and you don’t necessarily have to use matching rear and center channel speakers, especially if you have already invested a significant amount in your stereo monitoring set-up. Many monitor companies are selling their speakers individually these days, making it easy to purchase additional satellites and a subwoofer, building on your existing setup.
Volume Control:
On top of additional monitors, you will also need some sort of surround capable monitor controller, to act as a master volume knob. Most DAW interfaces only provide stereo master volume control built in. Remember, the Pro Tools master fader is not designed as a volume control, as this needs to be done at the analog stage after the D/A. Using the software mixer to control listening levels can seriously affect output resolution and is a major no-no in the DAW world. Many all-in-one surround sound solutions (like the ones from Blue Sky come with remotes, but there are plenty of companies that make a la carte surround monitoring controllers including SPL, Grace, and Dangerous Audio, among others. These tend to be super pricy, but the candidates currently up for the most affordable surround volume control are SPL’s “Volume 8 Controller” ($649 MSRP) and A-Designs “ATTY’2D” ($585 MSRP). I am sure creative mixers on a budget can come up with some additional “home-brew” solutions (I’ve heard of some people using the Behringer Ultralink Pro).
Surround Mixing in Pro Tools LE/M-powered with Mix51:
While you can easily set a channels output to any interface output, Pro Tools LE/M-powered does not feature built in support for surround panning inside the software. Because of this, Neyrinck audio has created a very clever plug-in solution called Mix51, which allows LE ad M-powered users to easily take their mixes into surround (providing you have the aforementioned hardware for surround mixing). At a list price of $189, Mix51 is a bargain and combining this with Digidesign’s DV Toolkit 2, you could have a pretty serious post-production rig on your hands.
How Mix51 works:
To get Mix51 to work, Neyrinck cleverly uses the same software API that multi-out virtual instruments use to send discrete audio streams to multiple aux return tracks (e.g., BFD, Kontakt, Battery, Structure, etc). Once mono or stereo audio is routed into the plug-in, Mix51 takes care of all the surround panning, surround effects sends and Center/LFE levels internally. After setting surround pans and levels within the plug-in, Mix51 automatically calculates the amount of signal it needs to send out to each of the 3 stereo (or 6 mono) aux return tracks that are in turn feeding your 6 surround speakers (L,C,R,Ls,Rs,LFE). Mix51 provides 3 main 5.1 busses and 3 quad FX send busses, for a totally of 30 discrete routing destinations. Sound complicated? It is really not that bad. Let me show you a basic workflow.
Using Mix51
First off, Neyrinck provides a great surround demo session with copious track comments that really breaks the process down quite well. But for starters you will need to first connect your monitors to the correct outputs on your interface. For Mix51, I recommend connecting the Left and Right mains to analog outputs 1-2, the Center and LFE (Sub) to outputs 3-4, and the Left Surround and Right Surround to outputs 5-6. Alternatively, you can set this up any way you’d like in IO setup, just remember how you connected your speakers.
For this simple demonstration I am only going to use a single surround bus and no surround send effects, again check out the great demo from Neyrinck for a more advanced usage example. I start by creating 3 new stereo aux tracks, and 3 new stereo master faders to act as my master bus outputs. After naming these tracks, I will also rename the outputs pairs to “L-R,” “C-LFE,” and “Ls-Rs.” To rename an IO path, simply right click on it and choose “Rename.”
I now create an additional dummy aux track labeled “srdmixer” and place the Mix51 Surround Mixer plug-in on it. The surround mixer plug-in can go on any existing track (except for the master bus aux and master fader tracks), as it doesn’t process any audio inline. After inserting the surround mixer plug-in, I now have access to the Mix51 audio busses from the inputs of my master bus aux tracks I just created. All I need to do now is set the inputs of my 3 stereo aux tracks to the appropriate stem feeds from Mix51, see the screen shot for a better explanation.
I then group these 6 tracks into 2 separate mix groups (on for aux and on for master faders) by selecting the tracks and choosing Track>Group. Grouping the tracks allows me to easily control the track’s level using a single fader.
Now that I have my surround bus masters and have inserted the master surround mixer plug-in, I can simply create audio tracks and add the Mix51 Panner as the last insert in the chain. Remember any audio fed into the Mix51 panner plug-in will not pass through to the track’s direct output, audio is captured by the plug-in and routed accordingly to your surround master aux returns. In other words, be sure to put any plug-in processing BEFORE the Mix51 panner, hence the “add it as the last insert” bit.
Because audio track inserts are pre-fader and the Mix51 plug-in steals the signal, if I want traditional fader level control on a track I can first route the audio track into an additional aux track via a bus, and then add the Mix51 panner to the aux track (making the panner post-fader in respect to original audio track’s signal). If you are concerned about wasting precious bus resources, you may opt to use the level control inside the Mix51 panner and insert the plug-in directly on the audio track, which works quite well actually.
Use the Mix51 panner plug-ins internal panning matrix to control pan, divergence, center channel percentage and LFE mix. You can automate any parameter inside Mix51 using standard plug-in automation techniques (read this article for a primer on plug-in automation). You can continue to add the Mix51 panner to as many mono or stereo tracks as your system can support.
Tips for using Mix51
• Look at the demo session from Neyrinck, seriously. It explains the usage of surround effects sends and multi-layer surround mixing using the 3 available 5.1 master busses and quad sends.
• Remember, rarely are all tracks in a surround session floating around all of the speakers. Many tracks in your session should be static and can be routed directly to your stereo mains (output 1-2) or directly to your center channel (output 3) without using the Mix51 panner on the track. On these tracks you can use a send to you LFE output to blend in sub effects.
• You may wish to create separate mono, master fader tracks to control your center and LFE channel master outputs. It is common to treat your LFE channel with a low pass filter, and while you could do this with an unlinked multi-mono EQ plug-in, separating the tracks out is a bit more intuitive.
• Bypassing a Mix51 Panner will allow audio to pass through to the normal output set on the track.
• Mix51 Panner automation is Pro Tools HD compatible, you can copy and paste pan automation to integrate seamlessly with HD’s built in surround mixer. In fact, Mix51 is completely compatible with Pro Tools HD as is, so you can easily open a mix and play it back with no fuss.
• Use the Mix51 surround mixer window to view metering and control master surround bus and quad effects send levels.
Coming up in Part 2:
Stay tuned, in part two I will discuss surround implementation in Pro Tools HD as well as show you how to bounce all this multi-channel content out of the system and encode it into a useable format when you‘re finished.
Pro Tools Tidbits:
• Massey Plug-ins has released a brand new de-esser for TDM and RTAS
Pro Tools Corner on MacMusic:
The fine folks over at MacMusic/440 Network have made me a VIP Moderator of their PC and Mac Pro Tools forums. Come on over and join the community!
PC Pro Tools Forum
Mac Pro Tools Forum
If you have a Pro Tools related question that you would like me to take a shot at answering or have any feedback, please send it to brian@audioMIDI.com. I will do my best to select the questions that seem to stump the most people.
As always, stay tuned to the audioMIDI.com eNews for the latest reviews and new product info.
| 
