Surround Mixing in a Non-Standards World (Part 2 of 2)

One of my favorite scenes from Jurassic Park is when Samuel L Jackson's character says "Hold on to your butts" with a cigarette butt hanging out of his mouth. What was about to unfold was a wild ride. Sometimes, I feel that way about this blog.

With all the standards surrounding surround sound (say that ten times really fast), the only consistency is the lack of one. I think standards are suppose to establish consistency. Unfortunately, everyone thinks their method is better and therefore, should be the "new" standard. The P&E Wing of NARAS have some excellent guidelines for surround mixing. They aren't trying to establish a single standard. However, the guidelines do help establish consistency.

Recently, I'd been asked to mix a music DVD in surround. The project was Leftover Salmon's New Year's Eve show at the Boulder Theater. It also happened to be their 20th anniversary show. A blue moon that evening added to the mysticism. Thankfully, I knew how it was tracked since I helped set up the recording rig.

When thinking about how to approach the project, I wanted to plan out my Pro Tools session for efficiency as well as creating the framework for down mixing. For those unfamiliar with down mixing, it is the way of creating a stereo or two-channel mix from the surround six-channel mix while minimizing phase issues, low-frequency buildup and other anomalies. We do it all the time in stereo mixing by listening in mono. If any instrument disappears, we have a problem.

I thought it best to start with a stereo mix and expand my astage from there. To start, I needed to build a series of sub masters. I created a 5.1 auxiliary return, a quad return, and two mono returns. The 5.1 return was for the reverb. The quad return is for everything and incorporated a low-cut filter. One mono return was the center channel and the other for the LFE (Low Frequency Effects) channel. The center channel had a low-cut filter. The LFE channel had a low-pass filter. Any track I wanted to be heard would be bussed through these sub masters. The sub masters in turn, were sent directly through the 5.1 master fader.

I know the Dolby Digital standard requires the crossover frequency for the LFE channel to be 110Hz. The DTS standard calls for 80Hz. See, already there's a conflict. Personally, I like the DTS standard. 80Hz still seems high to me. I can localize frequencies down to around 50Hz. But, I wanted my mixes to translate to as many playback systems as possible. Therefore, I chose 80Hz.

Now for the LFE decision. According ITU and SMPTE, the recommendation is to turn up the LFE 10dB. Most playback systems in people's homes follow this idea. It's the equivalent of the smiley face eq curve or leaving the "loudness" button on. Most people think it just "sounds better that way". At first, my thought was to leave the LFE channel alone. But, after playing some early mixes back on various systems, I decided to turn the LFE down 10dB to compensate for this bump. The only instruments I wanted in the LFE were the kick drum and bass guitar. So, I bussed the their signals through send outputs on their respective channels.

Now the center channel quandary. What to put in the center channel and how much? If I were mixing for myself, I'd have all the vocals in the center channel. Maybe a pinch of bass guitar and snare added for flavor. That's because I have a center speaker and it works. It works well. Apparently, I'm the black sheep. Most people either don't have a center speakers or if they do, is misplaced, misused or miscalibrated (not a real word, I know, but you get the point).

If the goal is to have these mixes play well on as many systems as possible, I needed to account for the mishandling of the center speaker on most environments. So, I opted for adding in just touch of the vocals and even less of bass guitar and snare. This effectively, tightened those instruments to the center. The vocals were brought up to about 10dB below the level sent to the front stereo pair. Bass and snare were around 25dB below.

The next order of business were the audience mics. At the show, there were two mics placed inconspicuously on the stage facing the audience. They were not placed in the back of the room. Okay, fine. I sent those tracks to the rear of the quad sub master. Initially, this sounded very cool, but quickly became tiring and distracting. I then moved those channels in between the front and the rears, favoring the rear slightly and turned them down a little. This added the "live" element and helped set the stage without detracting from what's happening on stage.

I then focused my attention on the stereo mix and was careful to not go crazy with panning and effects. I did bring the outside instruments further beyond the regular stereo field. This adds to the coolness factor of surround while maintaining phase coherency and down mixing compatibility.

The end result is a surround mix that sounds good in stereo too. By listening to just the left and right channels alone, I was able to gauge how it would sound on a stereo system. The room I used has GRace 906 monitoring system. This is extremely desirable for surround mixing. I could solo or mute any of the 5.1 channels. Now, if Blu-ray's 7.1 format ever takes off on the consumer level, I'll have to remix it. But, at least it will be close.

Next up for this blog; Over-compression and over-limiting. How do we fight back?