Engineers Compare Notes on Monitoring for Surround

WITH THE SUCCESS OF HOME THEATER SYSTEMS AND DVD-VIDEO, AS WELL AS THE UPCOMING LAUNCH OF DVD-AUDIO, there's no doubt that surround sound is a hot topic
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WITH THE SUCCESS OF HOME THEATER SYSTEMS AND DVD-VIDEO, AS WELL AS THE UPCOMING LAUNCH OF DVD-AUDIO, there's no doubt that surround sound is a hot topic in audio right now. As usual in our gear-crazy industry, much of the discussion has focused on the equipment that makes professional surround mixing possible-items such as consoles, recorders and outboard gear. But one of the fundamental (and unfortunately frequently overlooked) truths in recording is that the monitoring environment is the foundation on which the success of the mix rests. Good surround mixing starts with good surround monitoring.

Since surround sound is still quite new to the record industry, there remains much to learn about effective surround monitoring for music applications. As in much of audio, theories only take us so far; to find out the real scoop we need to turn to those brave few who are already in the front lines. Mix asked the following four engineers about creating the right conditions for surround mixing while avoiding potential pitfalls.

Michael Bishop, whose 25-year career in orchestral, jazz, blues and pop recording includes winning the 1997 Grammy Award for Best Engineered Classical Recording, is recording engineer and director of new technology at audiophile label Telarc Records in Cleveland.

Gary Myerberg-Lauter is a consultant on private studio setup for the likes of Bruce Springsteen, Trevor Horn and Bob Clearmountain, and co-designer of the 5.1 channel rebuild of A&M's Studio C in Hollywood, California, where he was chief engineer/director of technical operations.

Bobby Owsinski is a partner at Surround Associates in Studio City, California. His recent surround music credits include Pat Benatar, Cheap Trick, Tuck & Patti, Jimi Hendrix, and the Firesign Theater.

Michael Verdick is an engineer, producer and studio owner whose projects in the past 25 years have racked up sales of more than 30 million records. Currently head of A&R and chief engineer at Unitone Recordings in Glendale, California, Verdick's recent work includes a number of 5.1 channel DTS CDs.

Give an overview of the monitoring setup that you normally use (speakers/electronics, placement, room characteristics) for mixing 5.1 channel projects, and how it differs from the monitoring setup you use for stereo mixing.

Bishop: If I'm working a typical jazz or blues session in a studio control room, I use either five Paradigm Active 20s with the Paradigm Servo 15 subwoofer, or five Genelec 1031s with Genelec's Subwoofer. Classical sessions are usually monitored through a custom-made surround system from Waveform Inc., of Brighton, Ontario. It has integrated subwoofers and is powered by Threshold Class A amplifiers.

I use an L/C/R setup in an equidistant arc in front. It's important to me to have the center front at the same distance as the L/R speakers for time coherency. In my orchestral sessions there is a dedicated center front microphone that depends on the proper time coherency in playback or there will be image smearing. L/R speakers usually end up at around 60 degrees and the L/R surround speakers at 110 degrees, but actual positioning is determined by careful listening.

The control rooms I work in for orchestral sessions are pretty rough-often converted prop rooms, ladies rooms, green rooms, or lobbies. But most studio control rooms are actually more difficult to get a good surround setup in, since they often don't have enough room for proper spacing of the surround speakers. In fact, very few facilities have the right acoustics or space for a proper surround setup, so I always feel like I'm "winging it." I always have to keep myself rooted to my reference point to keep the mix in perspective.

Myerberg-Lauter: The theory we had at A&M was that the methods and practices established through years of record production should not change for surround. With that in mind, it's a must to provide switchable main and "mini" monitors. Our mains were designed in-house to be used as either 5.1 or stereo. They consisted of five identical dual concentric 15-inch speakers with a dual 15-inch subwoofer. In stereo mode the sub would reconfigure as a derivative L/R stereo pair. A 6-channel monitor matrix system was built in-house and provided the playback A/B switching, individual mutes and dim, and a fixed 85dB selector. The main monitors were focused at approximately 18 inches in front and behind the engineer's head in a diamond pattern. The mini system would be set up to the client's specification.

Owsinski: I'm often asked to try out surround monitor systems, so I've used just about every one on the market. The one I use most often is a Tannoy AMS-8 system, with a Martinsound MultiMaxx monitor controller and an M&K LFE-4 bass manager. For a sub I use a Tannoy PS115, although I also use an M&K when in a larger room.

Verdick: For surround mixing I like to use Genelec 1032s, with treble tilt set to -4. In terms of position, the distance between the left and right tweeters equals the distance from each tweeter to the mixer position, which creates an hourglass. The speakers are on their sides, with the tweeters as close to ear level as possible. The distance out from the mixer is dependent on the rear of the room, but ideally I like about six feet from the mixer position, especially if the console is not too large.

For surround mixing I don't like the room too dampened, and if possible not too much use of rear trapping or compression ceilings. If the room is too dead it sounds unrealistic and dry for me. It requires too much amplification, and can often result in an overuse of high frequency EQ compensation in the mix.

In stereo mixing I use an "on-the-console" speaker distance of about three feet. I use Genelec 1031s, because I don't require the bottom that gets lost when speakers are moved out three more feet.

What role do you think standard surround setup practices that were developed for theatrical film mixing (overall level, placement of rears, subwoofer level, etc.) have in determining surround setup for music projects?

Bishop: Like it or not, most home listeners will be listening to our material on a typical THX-certified home theater system. As KK Profitt recently told me, "Who's going to move their speakers after viewing Terminator just to listen to some music?" It's just not practical to assume anyone is going to do anything special to accommodate our recordings properly at home. That usually means dipoles on the sides or in the rear, so I have to keep in mind that anything I place in rear channels may not work as well in home playback as it does for me on my monitors.

Myerberg-Lauter: Although I generally agree with the film people on levels, I diverge from them regarding the rear speakers. I feel strongly that there must be five identical speakers in the array. No omni rears, and no bass management.

Owsinski: Many film practices for surround don't translate very well to music, which is what I mostly do. The 85dB standard doesn't apply because most music mixers listen at a variety of levels through the course of developing a mix. Also, in film you have focused panning, where panning to the center sends the sound to the center channel rather than to the middle of the soundfield. That usually doesn't work too well for music, which usually requires divergence panning to do what most mixers want to do. Film-style placement of the surrounds doesn't lend itself very well to music either. After all, they're restricted by the screen and we aren't. We don't mix music in stereo using film techniques, so why should we do that in surround?

Verdick: The single biggest difference in surround mixing for music projects is that to get the bottom response we need the same full range speakers for all positions. We also probably monitor at higher levels, because we are creating a complete room canvas. And since music projects involve constant sound rather than effects, which are more forgiving, we need a clearer, more defined subwoofer response. I think most music mixers are standardizing on a cutoff frequency for the subwoofer in the area of 75 to 85 Hz tops.

When mixing for 5.1, are you monitoring on five equal speakers (plus the subwoofer), or are the center and surround speakers smaller, as they are in many home theater systems? If all speakers are equal, do you take any measures in your mixing to accommodate listeners with smaller center/rear setups?

Bishop: All five main speakers are directional and equal, but I'm always considering the effect of perhaps deficient center or rear speakers when deciding what to put on those channels. I will usually place a source on left- and right-front channels in addition to the center-front channel, just in case the listener's center is a 3-inch speaker under a TV set. I can't help but feel I'm compromising the mix in accommodating what may be inadequate center or rear speakers, but that's the reality of what our material may be played on.

Myerberg-Lauter: We use the same methodology as we do in record production. The engineer using a large and a small system will be able to arrive at the best compromise that should translate well for most consumer systems.

Owsinski: I always use five equal speakers unless someone sends me a set to try that is otherwise-although I strongly encourage them to send all identical. If you're only sending ambience to the rears, then smaller or different monitors will suffice, but all the best mixes I've participated in had a lot of strong source material in the surrounds and were just plain loud. However, I do listen on an alternative set of small surround monitors-usually NHT M-00s-to hear what it will be like on a smaller, less powerful system.

Verdick: Where the unequal speakers will fail most is in the 90 to 160Hz range, the heart of most fundamental bottom for music. The problem of unequal speakers should be addressed at the consumer level, because unfortunately it simply doesn't work to compensate in the mixing stage for home systems with unequal speakers. If you try to fill more in the subwoofer-which has a different sound, effect and phase response-instruments such as bass will have one note too loud and another completely gone, and the mix will not sound good in any environment.

What role does the "near-field" concept play in your surround monitoring, and what distance do you prefer the speakers to be from the mixing position? Are you most comfortable with a situation in which the speakers are all built into the room (like the typical "mains" in a stereo room), or free standing?

Bishop: I much prefer free-standing monitors. I need the flexibility of positioning the speakers to my liking, and it is easier to adjust the acoustics of a control room with free-standing speakers. Getting a control room to be well behaved on all planes can be pretty difficult, considering the reflections set up by five main sound sources in a room.

Myerberg-Lauter: A well-designed room with soffitt-mounted "Rock 'n' Roll" monitors is best. That leaves plenty of room for an alternative mid/mini set.

Owsinski: I've been in situations where the soundfield was very large, and some that were very small. It's very difficult in the large situations to get sufficient level and headroom to fill up the room unless you have some pretty hefty monitors and power. I'm most comfortable at five to six feet.

The studio I'm doing most of my work in lately is Front Page Recorders. They have a ground-up 5.1 room with soffitt monitors that sound great. In this case, I use their soffitts not so much for the low end, but for a quick check, and to move some air for fun. But most of the work is done on the near-fields.

Verdick: I find that near-fields offer a more reliable and realistic environment. They're also very appropriate for the many home or small production studios that will start mixing in surround.

When mixing a project that will be released both stereo and 5.1, are you frequently switching back and forth between monitoring configurations when mixing? If so, are the stereo and surround monitoring setups completely separate? Do you use any particular technique to balance the monitoring setups for a smooth transition between monitoring modes?

Bishop: Telarc's orchestral sessions are always recorded directly to 2-track and 6-track for surround. So I frequently switch back and forth from stereo to surround monitoring. Luckily, a lot of those sessions don't require much active mixing. Once I get a sound and mix, things stay put pretty much for the duration of the session. An exception would be our Cincinnati Pops sessions that have a full orchestra plus rhythm section, soloists, keyboards, singers and more. On those sessions it gets a bit hairy to balance the stereo and surround mixes simultaneously.

The stereo and surround mixes may not have the same components making up the mix. For instance, some microphones used for surround may not be used for the stereo mix. For this very reason I am opposed to relying on a DVD player to do a downmix to stereo from our 5.1 mix. We have to supply a proper stereo and 5.1 mix for the release.

To keep the monitoring consistent between the two configurations, we calibrate the acoustic output of the two systems to be equal. However, once the artist hears the surround mix, they often don't want to hear the stereo monitors anymore.

Myerberg-Lauter: I find that the stereo process is done first and then the 5.1. EQ, dynamics and effects for each process require a completely different approach, so usually a serious 5.1/stereo mix will be exclusive and not derivative.

Owsinski: Stereo mixes and surround mixes are like apples and oranges and should be done separately. It goes the fastest when the surround mix is based on the stereo mix, however, so the stereo mix should come first. I'll listen on a pair of NS-10s and the main soffitt monitors before panning everything out.

While doing the surround mix, I listen quite frequently in both stereo and mono, which is easy to do thanks to a couple of switches on the MultiMaxx. If you calibrate all systems to the same level then the transition is always smooth. Most people don't know how to correctly calibrate a surround system-especially the sub and LFE portion-and that's where they get into trouble.

Verdick: I prefer to mix the stereo version first, then expand on what I've created for surround. They are such different experiences, mindsets and setups. So trying to do simultaneous mixes would be difficult for me. And folding down 5.1 for stereo doesn't work. Usually I've found that listening to the stereo mix is very unsatisfying after the surround version is available.

What observations do you have on subwoofer placement and level? Are you assigning to the sub channel much while mixing, or are you leaving it up to bass management to derive subwoofer material from the other five channels during playback?

Bishop: Ideally I like to have two subwoofers. The level is carefully set from listening to our reference recordings after basic alignment. I tend to have the subwoofers set 3 to 4 dB higher than the rest of the system. I'll usually assign sources to the sub channel while keeping in mind what a bass management system may do to the balance. I always assign some special effects to the sub channel on the sound-effects portions of our Cincinnati Pops releases.

Myerberg-Lauter: I always run dual subs, even on the mini system, and I place them between the center and L/R. With all 5 speakers at 85 dB, the sub is set to 92 dB. I am not a supporter of bass management in a 5.1 music scenario. In my view the engineer is the bass manager!

Owsinski: I've found that the actual placement of the sub in the room was only important in situations when I couldn't get enough level or headroom. As long as it's calibrated correctly at the mixer's position, then the placement doesn't seem to be too critical.

As far as assigning to the sub, if the mix requires it I'm not afraid to use a lot of LFE in addition to the low end stuff that gets automatically redirected to it. In fact, most of the best mixes that I've been involved in or heard used a great deal of LFE. The trick is what to send there so it doesn't get too muddy.

Verdick: In a live environment it can be difficult to set the subwoofer level with static tones. So I use my ears, with the dinosaurs from the DTS demo disc as a reference. Many matrixes cut off the response of the subwoofer channel to 85 Hz. If mixers don't listen through a matrix, and turn up the subwoofer to 150 Hz while mixing-which would really cause directionality problems-they could be in for a shock with their final release. This is why if you're listening straight through to the subwoofer, you should set its response no higher than 85 Hz.

I only assign music to the subwoofer that benefits from its frequency response. Since the phase and directionality is quite different, I paint or orchestrate with it for what it does best, not to compensate for what I can't hear somewhere else.

How do you see the design of control rooms changing over the next few years as surround sound becomes an increasingly important aspect of mixing music projects? Do you think stereo and surround mixing environments can happily coexist in the same room, or that separate rooms for surround-only are a better way to go?

Bishop: Of course we'll get better results with dedicated 5.1 or stereo mix rooms. I don't think one can really expect a room to behave properly for both systems at once. My best results have been from separately set-up control rooms. The only way to make a control room handle surround properly is to have a lot of cubic volume. Reflective surfaces need to be far enough removed from the speaker sources.

Myerberg-Lauter: Experience tells me to never build a room that is application specific. A&M Studio C worked equally well for both 5.1 and stereo production, and proved that coexistence is critical in a music studio if you want the room to remain booked.

Owsinski: The general trend I see in studio design has more to do with routing digital around the studio than worrying about 5.1, although there are a lot more 5.1 rooms springing up all of a sudden. Personally, I don't find the made-for-5.1 rooms that I've worked in to be dramatically different from normal stereo rooms, except for the fact that they naturally accommodate surround mixing requirements more easily. Stereo in a surround studio is a lot easier than surround in a stereo room, but it's not too much of a stretch either way if you know how to do it. Most quality surround monitoring systems give you at least as good a result in terms of extended frequency response as many studios' main monitors-though maybe that's not saying much for main monitors in general. The difference in facilities is more in the gear-consoles with surround panning and monitor systems, and multitrack machines such as Genex or DA-88-and the staff.

Verdick: The real issue isn't stereo vs. surround control-room designs. It's more whether a room is able to control the volume and response of large, built-in monitors, which require more trapping and design in specific areas. More mixers are ignoring large monitors and using near-field speakers, so the studios of the future will be designed for near-field, which by coincidence works for surround as well. Just don't get too large a couch, and leave room on the sides for speaker stands.