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Letters to Mix, August 2008

DOES EQ MEASURE UP? As an acoustician who specializes in small rooms, Bob Hodas' article (Room Tuning In the Box) and Michael Cooper's roundup of auto-EQ


As an acoustician who specializes in small rooms, Bob Hodas’ article (“Room Tuning In the Box”) and Michael Cooper’s roundup of auto-EQ speakers (“Intelligent Studio Monitors”) in the June 2008 issue were interesting and enlightening. But I feel the limitations of room EQ were glossed over, putting a positive spin on a technology that does not work as well as the vendors would have us believe.

In my experience, one or more deep bass nulls are the most common problem in domestic-sized mix rooms and are often caused by reflections off the wall behind the mix position. Peaks in a room are usually 6 to 8 dB or less, but nulls can be 30 dB or even worse. Such deep nulls are common and responsible for mixes that sound good in your control room, but sound bassy and boomy elsewhere. Nor can EQ reduce modal ringing, which is at least as damaging as the peaks and nulls. Yet reading the breathless claims for room EQ products, you’d think they can flatten the response and eliminate ringing, and do so for multiple locations in a room.

I’m not opposed to all uses of room EQ. In my living room system, I use the 1-band, cut-only EQ built into my SVS subwoofer to reduce a 40Hz mode by 3 dB. Bass traps are not very effective at such low frequencies, so in that case EQ can be a reasonable Band-Aid. But it’s still a Band-Aid. In small rooms, EQ is inappropriate at frequencies higher than about 50 or 60 Hz, and is never a substitute for proper acoustic solutions.
Ethan Winer

First of all, my article was not a product review, but a survey of available products and the technologies behind them. While equalization to correct response at the mix position will likely worsen the response elsewhere in the room, this is of little concern to proponents of room EQ. I would rather have one trustworthy spot in the room — my mix position — than have no place in the room I can trust. For people who mix alone, this is a non-issue

When applied correctly, room EQ does reduce the severity of room modes and can improve the accuracy of a monitoring chain. You are a proponent of that, as evidenced by your use of corrective EQ in the living room system.

We both agree that EQ is never a substitute for proper acoustic treatment. However, bass traps also have limitations. In my room, the traps decreased the amplitude of room modes by only a couple dB, yet also broadened their Q, greatly improving the overall response. It was the combination of acoustic materials and corrective equalization, however, that finally made the room sound great.
— Michael Cooper


Your recent articles on sampling rates and self-aligning monitors raise the same interesting question regarding human perception: To what degree are our perceptions of sound influenced by our own preconceptions?

In a recent study, wine experts were asked to taste two wines — one labeled as costing $5; the other $100. All of these pros described the superiority of the $100 wine in glowing detail, despite the fact that both glasses contained the same $5 beverage. And all of us may be prone to making this same error in judging audio equipment.

The problem with self-aligning monitors? The processing algorithms tend to be proprietary and invisible, so you don’t really know what’s happening to the sound unless you undertake direct measurement, as Bob Hodas did. And if you don’t know what’s being done to the signal, beware! The manufacturers of self-aligning monitors should provide a SIM or RTA display so their processing is made apparent.

Any compensated signal should best be used as one of many playback references and should not necessarily be trusted to be absolutely perfect. Our attitudes toward the equipment will inevitably affect our opinions, and unknown compensation schemes should be fully understood before being added to the mix.
Tony Eldon


Because our June 2008 issue focused on studio design and acoustics, we asked, “Whether a project studio or a full-blown multiroom facility, what was the most artistic place in which you recorded and why?”

One of the best studios I’ve ever worked in is Nebula Zone Recording [Fox Chase, Penn.]. This place has that magic feel all artists need to create the best they can, in the same vein as an Abbey Road or Electric Ladyland. As a producer and artist, it is and will always be my Mecca.

GK Labs Mastering [Gainesville, Fla.] is one of the most impressive places I have ever mixed and mastered in. The room features dimensions where the height, width and length of the room are based on a triad of the Golden Ratio. This room lets us mix and master for extended periods of time with less ear fatigue than I have experienced with other rooms.
Curtis Howard

It would have to be Swing House [Hollywood]. Their dedication to the creative process and the overall quality of the facility are unmatched.
David Klein

The most “artistic” place I record is right in front of my DAW with a full set of Marshall stacks off to the side, but using a set of Beyer DT880 headphones, which are partially open. This lets me hear the “band” in the ‘phones while still hearing — and feeling — the stacks. I definitely play differently when I feel that amp pumping next to me. Having the amp head in a control room and the speaker cab located in a distant room doesn’t feel artistic or real.
Joe Davis

The location is not what sets the artistic mood for me. If everyone’s competent and in sync — working together toward making the best product — all of the other issues seem to work themselves out. I’ll record in a rundown bus-terminal bathroom if the end result is a great recording. I just have to remember to wash my hands afterward!
Eric Carlson

In the next issue, Mix checks in on what’s new in the portable, handheld field recorder market. What’s the coolest place — or thing — you’ve recorded while using one of these handy, on-the-go units? E-mail us at [email protected]