September 2005 Reviewed by Anthony Di Marco	Polk Audio RM7400T / RM7302 / RM6901 / PSW505 Home-Theater Speaker System

Description Model: RM7400T floorstanding speaker Price: $574.95 USD each Dimensions: 36.5"H x 5.8"W x 6.63"D Weight: 19.60 pounds each Model: RM7302 center-channel speaker Price: $459.95 USD Dimensions: 24"W x 5.19"H x 6.63"D Weight: 12.25 pounds Model: RM6901 surround speaker Price: $199.95 USD each Dimensions: 12.5"H x 4.5"W x 5.06"D Weight: 5.20 pounds each Model: PSW505 powered Subwoofer Price: $589.95 USD Dimensions: 16.13"H x 15.13"W x 18.19"D Weight: 48 pounds System Price: $2599.70 USD Warranty: Five years parts and labor on speakers, three years on subwoofer.

Features Aluminum enclosures (RM7400T, RM7302, RM6901) MDF construction, including 1"-thick front baffle (PSW505) Power Port bass vents (RM7400T, RM7302, RM6901) Broad-dispersion design Dual 3.25" or 4.5" mineral-filled polymer Dynamic Balance midrange drivers (RM7400T, RM7302, RM6901) 1" or 0.75" Dynamic Balance silk/polymer-composite dome tweeters (RM7400T, RM7302, RM6901) 12" long-throw cone (PSW505) Real wood veneer (PSW505) Slot-loaded venting (PSW505) Hi-Roll woofer surround for longer excursion (PSW505) High-current, manufacturer-rated 300W continuous, 460W dynamic power amplifier (PSW505) Adjustable low-pass crossover, phase switch, and volume control (PSW505) Auto on/off circuit (PSW505) Unfiltered LFE input (PSW505) Pro-grade five-way binding posts, speaker inputs and outputs (PSW505) Magnetically shielded (all)

Interior decorating is all about synergy. The style of a chair has to work with the kitchen table, and the paint on the wall has to complement the colors in your sofa and carpet. The same can be true for audio and video components -- especially when it comes to peacefully coexisting with your significant other. Low-profile plasma and LCD displays have presented a challenge to loudspeakers designers. These TVs have the advantage of being able to be mounted flat against a wall, while most loudspeakers need to be positioned away from a wall. Placing a speaker too close to a wall typically results in muddy, congested sound.

Many mass-market speaker manufacturers are satisfied with simply selling product. However, Polk Audio, of Baltimore, Maryland, has succeeded as both an innovator and a brand name by mixing engineering prowess with strong marketing. The company’s RM series is designed to offer good sound in a slim-line package that complements the newer display technologies. I reviewed the $2599.70 RM7400T-based home-theater speaker system.

Titanium color, aluminum skin

The lightweight RM series are well assembled. Each aluminum speaker enclosure has a rigid, silvery-gray baffle of high-impact polystyrene, and a grille that wraps around the top (and the bottom of the RM6901 surround and RM7302 center). At the top of each enclosure is one of Polk’s patented Power Port bass vents, which allegedly improves the lower-midrange frequency response while allowing the speaker to sit in close proximity to surrounding walls.

According to Polk, the RMs’ curved shapes and internally ribbed, aluminum skins not only provide a rigid structure but also reduce internal standing waves. Rapping on the side of the RM7400T main and RM7302 center enclosures revealed a slightly hollow sound. The smaller RM6901 surround exhibited less of this behavior.

Each speaker has two midrange drivers flanking a single tweeter in what Polk says is a true D’Appolito arrangement and crossover design. The midrange drivers use a mineral-filled polymer cone, while the silk-dome tweeters are impregnated with polymer for increased strength. The RM7400T main and RM7302 center use 4.5" midrange drivers and a 1" tweeter, the RM6901 surround a 3.25" midrange and a 0.75" tweeter.

The PSW505 powered subwoofer gave a very good first impression. This solid, well-built, medium-sized sub’s 12", high-excursion cone has a huge surround and is driven by a 300W amplifier. According to Polk, a slot on the lower rear lessens air turbulence for more controlled bass, with none of the chuffing of traditional round ports.

Nearly "invisible" placement

In my room, the PSW505 subwoofer had to be placed in plain sight, next to a sectional sofa. And although its silver baffle looked better with the grille off, its black wood-grain finish won it no admirers. On more than one occasion, visitors would comment on the attractive looks of the RM series while politely denouncing the PSW505.

To begin, I placed the RM7400T main speakers about 20" from my front and sidewalls, and Polk’s largest RM-series surround speakers, the RM6901s, to the sides of my listening position. Like all center-channel speakers, the large RM7302 took up residence atop my Mitsubishi WT-46809 display. Over the course of the review I moved the Polk surrounds within 5" of the back wall, and toed the main speakers in about 15 degrees.

Connecting the RMs proved somewhat aggravating. Their plastic binding posts belied the speakers’ good looks -- the shiny, slippery nuts were difficult to tighten and always seemed a little loose. I used both bare wire and high-quality spades, but neither seemed to make a difference.

One design choice I question involved an aspect of the RM6901 surround’s classy and very functional stand. The miniature stand can be affixed to the rear of the 6901 with two Phillips screws, but once installed, the stand blocks the 6901’s binding posts. (This was done so that the speaker wire could be hidden inside the stand’s hollow pole.) During the review I had to remove the stands to retighten the slipping posts -- it would have made more sense to use spring clips. It would also help if the stands’ mounting screws were permanently affixed in their holes with lock washers. Not only that, but installing the stand required running the speaker cable through the pole, connecting the wires to the binding screws, placing the speaker, sans grille, on its baffle (taking care that nothing poked the now exposed tweeter), and holding the bottom-heavy stand steady while aligning the screws and removing any slack from the speaker cable. It required three hands to do this job effectively.

Hooking up the subwoofer was simple. The PSW505 comes equipped with all the standard hookups and adjustments expected in a subwoofer at its price. Controls for crossover point, subwoofer volume, and phase take up the top portion of the rear panel, alongside the line- and speaker-level connections. A welcome feature is a separate LFE input that bypasses the PSW505’s variable crossover. The PSW505’s five-way binding posts felt slightly more substantial than those used on the RM series.

Sound

At first listening to the RM speakers on their own, I found their bass response wanting, despite Polk’s Power Ports. Moving the speakers closer to the walls improved their midbass performance a bit, but switching in the PSW505 sub yielded the best results. Without the PSW505, the lower midrange sounded withdrawn. Dialogue-heavy films such as Sideways sounded thin and recessed, while the chaos of chapters 19-21 of Matrix Revolutions lacked midbass punch. The PSW505 corrected this, laying down a foundation of bass that gave weight to voices and punch to drums. In my setup I chose 80Hz for the crossover point, which helped flatten out my room’s 60Hz bump.

The PSW505 didn’t try to trick the brain into thinking it was going lower by boosting a specific frequency, and did a very nice job of conveying the deep bass produced by the explosions in chapter 17 of The Core. Such solid bass tightens up imaging and provides a foundation for the higher frequencies. During the opening of Disney’s Atlantis, the Atlantian fighters shook the floor.

Like other speakers I’ve heard in their price range, the Polks favored a warmer, less extended treble response. The cling and clang of swords during the exciting "Battle of Pelennor Fields," in chapter 37 of The Lord of the Rings: The Return of the King, didn’t have those last bits of bite and refined sparkle. Instead, the Polks added a slight euphonic quality that contributed a bit of sugar to the sound that may benefit some soundtracks. The overall timbre was pleasant if not absolutely resolving. These polite high frequencies took a little away from the tension and mood of chapter 9 of Signs.

The Polks handled surround sound and voices competently when supported by the PSW505 sub. Panned effects cast wide, deep images in my room, while voices remained rock steady and intelligible, even in chaotic scenes. The F5 tornado at the end of Twister felt tangible enough to cause goose bumps, and the flying vampires in chapter 5 of Van Helsing seemed to be diving for me. These examples made it apparent that the RM7400T, RM7302, and RM6901 were all cut from the same sonic cloth.

The RM7400Ts’ polite sound made them unable to handle all music effectively on their own. Jesse Cooke’s Gravity [CD, Narada 63037] sounded clean and quick, with slightly sweetened guitars, but Cooke’s guitar didn’t have the effervescence I hear through systems with more high-frequency resolution.

Many speakers in the Polks’ price range tend to compress dynamics, but most good speakers have no problem playing back the limited dynamic range of pop and rock music. Things get dicey when you ask these same speakers to handle crescendos from the likes of Mahler and Bruckner. The Polks didn’t lose their composure, however. Although they didn’t possess all the weight and slam I’ve come to expect from Leonard Bernstein’s excellent late recording of Mahler’s Symphony No.3 [CD, Deutsche Grammophon 427 328-2], their reproduction of it was engaging.

The RM series offered good lateral imaging. On BT’s "Lullaby for Gaia," from ESCM [CD, Reprise 46799], the swirling tapestry of synthesizers and samples floated between the loudspeakers. The Polks sounded fine as long as they were anchored by the PSW505’s tightly controlled bass.

Other choices

Although RBH’s AC Series System 2 loudspeakers ($1759) target the same buyer as the Polks, the designs are quite different. The AC enclosures are made of "composite-reinforced MDF," not the RM series’ aluminum and high-impact polystyrene. The RBH speakers are more traditional two- and three-way designs that use a round front port for bass reinforcement, while the Polk’s two-way D’Appolito design and Power Ports are a bit less usual. While the Polks’ lighter-weight aluminum cabinets may look classier and more cutting-edge, the weight and solidity of the ACs made me feel more confident. Add some killer binding posts and clean fit’n’finish, and the RBH system betters the Polks in terms of apparent solidity.

The RBH AC-5T tower speakers throw a full image and deliver tight bass without the help of a sub. The RBH AC system also sounded more cohesive and seamless than the Polk RM. Image density, overall sound quality, and price all point to the RBH system as one of the best values around.

However, Polk outguns RBH with the PSW505 subwoofer. Yes, the PSW505 is a larger subwoofer than the RBH A-10S, but for the money, it easily compares with the likes of Hsu Research’s outstanding VTF-4. The RBH AC-10S is simply outclassed by the Polk when it comes to tightness and output capability.

Looks and sound

LCD and plasma monitors are flying off the shelves, many of them becoming parts of high-quality home-theater systems. Polk’s RM system will look great next to one of these. The system will appeal to those seeking the sleek look of their aluminum enclosures, though more traditionally constructed speakers that I compared them with seem to have an absolute performance advantage. You’ll have to decide what’s most important to you and what tradeoffs you can live with. Polk Audio offers some alternatives that might fit your sonic priorities better. Then again, the RMs’ looks are pure next-generation and their sound is quite respectable, and that might fit your bill perfectly.

Manufacturer contact information:

Polk Audio
5601 Metro Drive
Baltimore, MD 21215
Phone: (800) 377-7655

E-mail: polkcs@polkaudio.com
Website: www.polkaudio.com

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