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Lexicon VR4 EQ with Revel Speakers Demo

by January 09, 2005
Filed under: Loudspeakers

Talking about speaker designers who understand room acoustics, take a look of the four shots of the Lexicon/Revel suite. In the first shot the Lexicon electronics sit atop a wooden cabinet to the left of the left-center-right speakers. Note that the wood cabinet's front face is completely blocked by two ~20"W x ~4.5'H x 1"-2"D absorptive panels. That takes care of first order reflections from the left-front speaker. (Note also the odd size of these panels. This indicates that Revel had the room checked out a head of time and figured the exact size panels they needed for their demo, which would allow the Lexicon electronics to be mounted atop the cabinet. This layout was planned and cleverly so.)

In the second photo you see new Revel C12 center channel speaker (2 x 6.5" woofers, 4" midrange, 1" tweeter, $500), Revel F12 right-left tower speakers (2 x 6.5" woofer, 5.25" midrange and 1" tweeter, $1200/pair) and the Revel B12 subwoofer (10 woofer w/650W amplifiers, $1000).

Not shown in the photo but rounding out this new "CONCERT a " line for Revel are the M12 (6.5" two-way, $600/pair) and the S12 surround speaker (2 x 5.25" mid-woofers, 2 x 1" dome w/waveguide tweeters, $500 each).

[DAY1_074] Note the absorptive panels just behind the left and right front speakers, slightly offset toward the center. The listening position(s) were almost exactly 2/3rds the way back into the room and consisted of a stuffed, cloth-covered sofa where about four Lexicon/Revel dealers could sit comfortably. To the left and right of the sofa and slightly behind were the M12 6.5" two-ways which most times were blocked by other listeners in the room who stood behind the sofa. Come to think of it, those standing listeners along with the two panels behind the front-left and front-right main speakers probably made for an excellent slap-echo killer.

The third photo shows the right side of the listening space. The spacing of other members of the Revel family of speakers serves to break up upper bass region waves and the light but folded drapes do a decent job of attenuating the mid-high to high frequencies. Regarding further room correction that had taken place, Jeremy Frost, Lexicon's newly promoted Product Manager noted that the room had had a significant bass peak which had been removed via the single-band parametric equalizer on the B12 subwoofer. There is a manual toggle switch on the B12 subwoofer with toggle used to switch the single band of room correction in or out. So because Jeremy wanted to be a ble to switch from EQ-in to EQ-out electronically via the MC12 prepro, the single band parametric stayed in circuit (correcting the worst offending peak) at all times.

[DAY1_076] It was time for the demonstration of the V4 EQ room equalization module available as a retrofit for Lexicon's MC12 prepro at $2995. Jeremy started out "As you can see this room is not exactly ideal for listening. We'll start out with Logic 7 two-channel music (from CD) ." He then proceeded to play " Fever " by a male vocalist. After playing the sparsely orchestrated cut which featured slow finger snapping, a string bass and the male vocal Jeremy explained a bit more a bout Lexicon's purist approach to room correction." The V4 EQ uses seven bands of equalization which cover the frequency range from 19Hz to 250Hz. Above that frequency we recommend the more traditional approach to room correction which usually involves proper placement of absorptive panels such as you see around the room. We have four settings 'low, medium, hi and max'. We're using the medium setting which seems to be the best compromise in this room."

I asked "You're using FIR filters on these, right? " Jeremy answers " We can set up to seven filters per channel for all 10 channels that the MC12 has. That includes left, center, right, two side speakers, two surround speakers and a complement of up to three subwoofers. The V4 EQ actually measures beyond the 250Hz range to make sure we aren't missing any broad Q resonances that extend beyond that range but we're only actually doing the correction below 250Hz. "

[DAY1_077] And the frequency resolution accuracy? "We're measuring to 0.73Hz." I asked "How do you handle the subwoofer (.1) splice to the full range speakers? " And Jeremy replies " It looks at the system as if there were no crossovers in place. So even if you have resonances below the crossover it will act as if that crossover isn't there and still place the filter. We've found that we usually don't use more than 3 or 4 filters per speaker because it's based on audibility and that's based on several things; the frequency, the Q and how audible that is. So we only put filters on those resonances which are audible."

"And multiple subwoofers are just fine with the system?" Jeremy, "Sure, using multiple subs is always recommended. That would give you smoother response to begin with. Especially if you place 'em right. This man's shaking his head, but I disagree." A listener on the right side of the sofa just in front of where I'm standing adds his experience, "I've done over a dozen rooms and multiple subs are almost always most problematic. I've done the half wall thing, the (Floyd) Toole (Todd Welti) recommended procedure and at least in my room it makes a significant worsening of over all (low bass) frequency response at multiple listening positions ." Jeremy responds, "I would argue that the best locations probably were not chosen for the placement of subwoofers in those rooms."

I then ask about the set-up procedure for the V4 EQ and Jeremy talks about the four microphone "every-seat-a-good-seat " averaging technique (as espoused by John Dahl of THX in Part 2 of The CEDIA seminars. "The system actually works completely automatically. With all 10 speakers hooked up you turn it on and it takes 13 or 14 minutes to complete its calibration."

We then went back to listening to a couple more music selections. I was standing to the right of center and about 2 1/2 feet above the best listening angle so I knelt down behind the sofa to put my ears between the plane of the midrange and tweeter drivers on the left-right Revel F12 three-ways. There was very little difference to be heard with the system in or out!

One got the impression that most of the assembled dealers were a bit under whelmed with the V4 EQ demonstration. Your author on the other hand was quite impressed. I realized what the Lexicon/Revel team had accomplished with passive room treatment, excellent, flat-response speakers (especially above 250Hz), and finally, when all was set up properly, the application of electronic room correction. The V4 EQ room correction system is a purist set-up which will do its job best in a painstakingly set-up listening room or home theater. It will most probably not imposeanoticeably negative sonic signature on such an installation. And that is the purpose for which it was designed. We look forward to reviewing the best priced Revel speakers ever and possibly the V4 EQ room correction. www.harmanspecialtygroup.com .

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Gene manages this organization, establishes relations with manufacturers and keeps Audioholics a well oiled machine. His goal is to educate about home theater and develop more standards in the industry to eliminate consumer confusion clouded by industry snake oil.

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