A/V RoomService “Metu” Acoustic Panels (TAS 199)

 

Room treatments are, in my experience, mixed bags. There is a thin line between damping resonances and overdamping the entire musical presentation. The trouble is that most traps and wall panels damp or diffuse more or less everything equally above and below certain frequencies—they act like shotguns in situations in which you need pea-shooters. Up until now I’ve preferred to mix non-traditional items, like the Shakti Hallographs (which dramatically change soundstaging, timbre, and dynamics without much of a concomitant dampening effect), with a smattering of diffusors like RPG Skylines or Abfusors, which do provide some dampening of specular highlights (and are excellent when used behind the listening position or behind speakers or both).

My mix of Hallographs and RPG items has worked just swell in my upstairs listening room, but recently I turned my downstairs study into a second listening room and though it is virtually the same size as the room above it (albeit with slightly taller ceilings) it sounds more alive and echoic. Enter Norm Varney of A/V RoomService, Ltd.

Norm is the guy who designed the whole-room acoustical treatment that Robert Harley uses. Of course, the panels and traps that Robert uses are built into his walls and ceilings and took a tremendous amount of computer-modeling to perfect. I didn’t want the whole enchilada. I wanted something that would tame the first reflections of the CLXes (which, unlike most dipoles, do project sound toward the side walls because their panels are curved) and also handle a particularly irksome 100Hz bass node.

A/V RoomService Ltd. is the wholly independent company that Norm and Harry Alter (Senior Engineer at Owens Corning Science & Technology Center) started. Both Norm and Harry are highly educated, highly experienced acousticians. Their products aren’t playthings and they don’t install them willy-nilly. I was asked to send Norm a to-scale drawing of my study, with all the dimensions carefully recorded, and to supplement this with photographs that illustrated unusual architectural features (like a built-in bookcase in one corner or a fireplace along one wall). From these data Norm generated an acoustic model of my space—and its primary resonances.

I was interested in something portable—something I could freely move around (or remove if I didn’t like its effect). Happily, AVRS had just introduced its “Metu” Acoustic Panel products—wall-hanging acoustic panels designed to “blend into” listening rooms rather than to give them the decorated-with-egg-crates-look of most acoustic panels, as if your interior decorator were Tyson Farms. The Metu products can be painted to precisely match walls or can be made to look like framed photographs, posters, or prints (of your choosing). Covered in a porous fabric and/or capable of accepting drum-scanned artwork, the Metus’ 1.25" high-frequency-equalizing acoustic panels (and their backerboards) provide reactive and diaphragmatic absorption from about 100Hz to above 8kHz—perfect for first reflections, while their 1.25"-thick, tuned, bass-equalizing corner traps work the same trick from about 50Hz to above 8kHz. (Some assembly is required with each item.) Both are said to achieve an average “noise reduction coefficient” of 1.00 (whatever that means).

The panels can be had in various sizes and, of course, finishes (and so can the wood backerboards). After a bit of computer-modeling based on the data I’d sent him, Norm recommended a “starter kit” for my study, consisting of four wall/ceiling Metu panels and four corner traps.

Frankly, on the basis of past experience, I wasn’t sure I was going to like the effect of AVRS Metus, but I did. They seemed (and seem) to precisely solve the problems I was having with first reflections and midbass resonance, without softening dynamics or desaturating timbres. On the contrary, dynamics were improved and so were density of tone color, imaging, and soundstaging. Pretty damn impressive. Downside? I can’t say this was problem for me, but as with all room treatments it is possible, I’d guess, that too many of the very effective Metus might overdamp a space, so stick with Varney’s recommendations and don’t overdo it.

Comments

lateralgs (not verified) -- Thu, 02/04/2010 - 11:42

Perhaps this isn't the place or time, but since they were mentioned....

I fully comprehend the proof is in the listening, and sometimes this must "simply be enough" of an explanation, since, after all, listening is the point of the whole hobby. But as an engineer, I am continually compelled to ask the simple question, "How does this work?"

I have read many differing opinions about the Hallographs. I understand there are many variables potentially affecting any efficacy they may have. Nonetheless, from a pure physics standpoint, I cannot get my head around WHY they should have ANY impact at all.

I would love to be illuminated from a purely scientific perspective as to why they can and do have the effects some people claim for them, especially given the price of entry. Is it possible it is purely down to psychoacoustics?

It is much easier for me to comprehend the potential effects of reflection dampening and other physical dampening materials and techniques. But I just don't "get" the Hallographs. In fairness, I have never experienced them.

brion -- Fri, 02/05/2010 - 22:29

....as I understood it, the person who "did" Harley's room was originally with ASC, the originators of room-taming devices, Tube Traps. It would seem the mechanics of all the room taming devices is similar.
While Jonathan finds most devices to overdamp or underdamp, I find Tube Traps to be quite effective -- if one realizes that they must be moved down walls in tiny, TINY increments. Once in the right position, they must then be turned in equally tiny movements to the the right or left. I've had them for 20 years, and I still find myself adjusting them each time I move the speaker position.
As for the Hallographs, they really are terrific devices. I used them and they focus images extremely well, better than Tube Traps. But the 'Traps work extremely well.
I'm sure there are many devices that work well, but I find most people simply plop them down and don't spend enough time putting them into EXACTLY the right position. Tiresome? Yes. But note that JV had to send exact dimensions of his room, including bookcases and fireplace positions. There's no free lunch in room acoustics. Positioning is EVERYTHING.

Philly (not verified) -- Fri, 02/19/2010 - 14:44

Great points. Anything you stick in a room will have some impact on the sound. Put four apples under a cd player and the sound will change, as the apples rotten and soften the sound will change. Same affect with cables, all have impedences that will work better with some gear than others. Not snake oil because you will hear a change, but for the cost of somes wires (as much as a car), and the rest...pure greed and BS to sell it, spin and half baked truth both mixed with fact and fiction or theory as they call it.

The audio press years ago brought into it and sold on the public, today you do not see much on power cords and wires from the press, because it is and always was a crap shoot on how they would interact within a system. Like a good poltican they spun then covered their butts after developing a new industry in audio...the $1,000 a meter wire, and that is cheap compared to some.

The room though is a big part of the final sound though so care must be taken to improve it and it is worth the final cost if done properly. But that is the hard part, know what your doing or hiring someone who does.