There are widely varying opinions about acoustic room treatments. Some say it is very important, while it never crosses the minds of others. There are also differing opinions about which types of room treatment, absorbers or diffusers, are most effective. As with everything in life, one size does not fit all. The answer is, It depends -- on your room’s size, layout, and furnishings, the type of speakers you have, and your personal preferences. With all of the room-treatment products out there, it’s daunting to figure out how much is enough, and what you should buy.
Primacoustic, a division of Radial Engineering, Ltd., based in Port Coquitlam, a suburb of Vancouver, British Columbia, in Canada, thinks that their solutions will help many of the music-listening and home-theater rooms out there. Their bread and butter has been providing acoustic treatments for commercial markets and recording studios; most recently, they’ve begun to make inroads into the residential market. Their product offerings range from bass traps, absorbers, and diffusers to speaker isolation and ceiling diffusers.
I stumbled on Primacoustic by accident. A local audio representative, Len Gerling, of Gerling Ventures, asked if I’d be interested in trying out one of the Primacoustic kits, which are packaged for recording studios but can be adapted for use in homes. Being of the it-never-crossed-my-mind camp, I eagerly said yes. I gave Primacoustic my room dimensions and they offered the London 10, which sells for an affordable $499.99 USD.
The London 10 is one of four kits offered by Primacoustic, which range from the London 8 ($199.99) to the London 16 ($1499.99). Each kit is made for a different size of room, the London 10 being appropriate for a space of 100 square feet. Although my room is larger than that, its L-shape and layout make this kit suitable. The kit consists of 20 panels -- 8 Control Columns, each measuring 48” x 12” x 2”, and 12 Scatter Blocks (12” x 12” x 1”) -- as well as 20 Surface Impalers for mounting, and drywall screws and anchors.
The Control Column is made of six-pounds-per-square-foot glass wool, which is fully encapsulated with a mesh. The edges are resin-hardened so that the wool won’t fray or come apart, then covered in acoustically transparent cloth in one of three cloth colors: black, gray, or beige. The Columns have beveled edges for a more attractive appearance. The Scatter Blocks are made up of the same materials, except that the glass wool is 1” rather than 2” thick. The edges of these panels are also resin hardened, but not beveled.
The claimed sound-absorption coefficient of the Control Columns is 1.0 from 4000Hz down to 400Hz, dropping to 0.34 at 100Hz. This means that 100% of the sound that hits the product is absorbed in the frequency range of 400Hz-4000Hz, but only 34% of the sound at 100Hz is absorbed. These numbers compare favorably with products from other makers of acoustical panels made with other materials, such as rock wool. For lower frequencies, you’d need thicker panels.
How room reflections affect sound quality
For listening to music at home, buying the right gear is only half the battle. The other half is your room, which greatly influences how your speakers will sound. The room’s effect can be minimal to huge, depending on how your speakers were designed. Some highly directional speakers have a narrow sweet spot where the soundwaves from each speaker intersect, your room’s sidewalls having less influence on the sound. Most speakers, however, produce ample room reflections from the wall behind the speaker (i.e., the room’s front wall) and the sidewalls. From Floyd E. Toole’s book Sound Reproduction: Loudspeakers and Rooms, I learned that room reflections affect sound quality in many ways: localization, spaciousness, timbre, and intelligibility of speech.
Room reflections can negatively affect localization. If the reflected sound is loud enough, as in a room with glass walls, you’d have a difficult time figuring out where the sound was intended to come from. If, however, reflections are loud enough and delayed enough compared to the direct sound, your ears will hear the reflections as a separate event -- it will sound like an echo. Nor is getting rid of all room reflections a good thing, as they are what give recordings a sense of spaciousness, and the vast majority of listeners desire some spaciousness. Reflections can affect timbre both negatively and positively. The pitch of a musical note can be fundamentally changed by room reflections. On the other hand, according to Toole, reflective spaces enhance our ability to hear resonances, which makes instrumental sounds richer and more interesting. The intelligibility of speech is also enhanced by the proper amount of room reflections.
The key to better sound is to have a satisfying balance of direct sound and reflected sound that is sufficiently but not overly damped. As a contrast to a lively room with glass walls all around, in which there is a great deal of reflected sound, think of listening to music in an anechoic (literally, an echoless) chamber. I can attest to how undesirable the latter is -- I’ve been in the anechoic chamber of Paradigm, near Toronto. A room that reflects no sound is great for measuring speakers, but it gives you an eerie feeling for listening to music or speech. In fact, it takes a lot of concentration to understand the speech of anyone speaking inside such a space.
Setting up the London 10 in my listening room
Primacoustic claims that its London 10 kit achieves a balance of reflected to attenuated soundwaves by incorporating the concept of Live End Dead End (LEDE) from music mixing studios. The Live End is the area behind your listening seat. This is where the direct sounds from your main speakers hit the wall after they’ve hit your ears. The idea is to use the Scatter Blocks to diffuse this sound, to prevent flutter echoes: i.e., sounds bouncing back and forth between parallel walls. The Dead End is the area around your front speakers. The sounds reflected off these walls are attenuated using the Control Columns.
My home-theater room has an L-shape; its longest wall is 24’ long. My projection screen is on the right half of this long wall. My listening-viewing seat is 14’ away from the screen, with the back wall 16’ from the front wall. The back wall, parallel to the longest, front wall, is 14’ long, and includes a 4’-wide doorway to the next room.
Primacoustic’s James Wright came to my house to set up the London 10. He set up two Control Columns on either side of my projection screen, to attenuate the front-wall soundwaves. Along the right wall, three Control Columns were placed to attenuate the first reflections, and areas slightly forward of and behind the first-reflection point. With the opposite wall 24’ away from the right wall, I didn’t think it would matter to have these sidewalls attenuated, but Wright placed two Control Columns on the far, left wall, and another on the closer wall. On the back wall behind my listening seat, the Scatter Blocks were placed in a checkerboard pattern, alternating with blank spaces. All of the panels were installed using the included Impalers, but rather than screw these into my walls, Wright used 3M Command strips to secure the Impalers to my walls, so that the panels could be easily taken down after the audition without permanent damage to my walls.
The setup took no more than an hour, and the placement was surprisingly unscientific. Wright took no measurements, neither with a measuring tape nor with any sound-measuring devices. His long experience with these panels guided him to the best locations for them, with lots of hand claps, then listening for reflections of those claps.
Performance with music
I had always known that my home-theater room was reverberant and lively. The walls are stark, the ceiling is T-bar with hard surface panels, the floor is cork, and the furnishings consist of a few bookshelves. The only plush, sound-absorbing features are a sofa and a loveseat. There are problems in the bass -- audible peaks and valleys as I walk around the room. Despite these problems, the room’s sound is bearable, which I attribute to two things: my ears and room correction. No, my ears aren’t better than yours, but I’ve gotten used to the space over the years. At some high ear/brain level, I’m able to partially mask or ignore some of the reverberation. One way in which the liveliness of the room is manifested is in listener fatigue. This is why I prefer mellower speakers for long listening sessions. Some of the reverberation can be reduced by adjusting the frequency response with Audyssey’s MultEQ XT32 program, which is included in my Integra DHC-80.3 A/V processor.
Having optimized my system before the installation of the London 10 kit, I expected to hear only a small improvement in sound quality. I couldn’t have been more wrong -- the improvement was huge. Even as James Wright pulled the panels from the box and leaned them against the walls, I could hear the reverberation decreasing -- no music was playing, but as we talked, our voices grew clearer and easier to understand. And when I settled in to watch movies and listen to music, it was clear that the many improvements spanned all facets of sound quality.
For two-channel listening, one of the biggest improvements was in imaging focus, which I noted when listening to “Bye Bye Blackbird,” from Patricia Barber’s Nightclub (SACD/CD, Premonition/Blue Note/Mobile Fidelity Sound Lab B0000634I5). This recording has a minimalist arrangement: voice, piano, bass, drums. Normally, I hear a larger, more diffuse image of Barber’s voice between the speakers, which causes me to move my head in search of the sweet spot. With the London 10 in place, her voice was solidly equidistant from my two main speakers. The image of the piano during Barber’s forceful solo was razor sharp -- I could follow the movements of Barber’s hands. This wasn’t nearly as evident during listening sessions before the London 10 was in place.
Another improvement was eliminating my room’s high-frequency resonances. This hadn’t been obvious before I had the Primacoustic kit installed, but it was quite apparent afterward. It’s one of those problems that you don’t think you have, but its absence can be glaring. With this resonance, any long, sustained high-frequency notes cause excess high-frequency energy in the room, resulting in listener fatigue. For example, I listened to “Sopping the Biscuit,” from the Roy Hargrove Quintet’s With the Tenors of Our Time (16-bit/44.1kHz FLAC, Columbia). This features Hargrove on trumpet, with a variety of tenor saxophone players weighing in. All of those high frequencies can easily overwhelm my room unless the speakers, room correction, and electronics are carefully matched to reduce the brightness. This system matching wasn’t as critical with the London 10, and made already good-sounding speakers sound that much better.
A third improvement was in the upper bass, which surprised me -- according to Primacoustic, this is where the London 10 panels are less effective. But I heard a tightening of the bass -- or perhaps it was the bass harmonic frequencies that became tighter. Nevertheless, when I listened to jazz with double bass -- for example, Super Bass 2 (SACD, Telarc SACD 63483) -- the bass notes from Ray Brown, John Clayton, and Christian McBride were more distinct across the front soundstage. This album can sound muddy and vague when all three are playing, but the London 10 sharpened up the imaging by reducing the resonance through my room.
One area in which the London 10 had no effect was the low bass. This was to be expected -- the kit contains no traps specific to bass frequencies, although such traps are available from the Primacoustic website. When listening to pipe-organ music, such as a transcription of Mussorgsky’s Pictures at an Exhibition (CD, Teldec B000001Q80), I moved around my room and noticed that the deep-bass response varied widely. Bass was especially strong in the right rear corner of the room. According to Primacoustic, to absorb the lower bass response, you’d need thicker panels, such as their FullTrap, which has a suspended diaphragm in addition to the acoustic insulation. Additionally, leaving an air gap between wall and panel increases the panel’s acoustic performance -- any soundwaves that get through the panel can be reabsorbed when they bounce off the wall.
During the course of this review, I received new speakers -- Definitive Technology’s BP8060ST towers. These feature what DefTech calls a Forward Focused Bipolar Array, which differs from conventional bipolar speakers in reducing the rear driver’s output by 6dB. Bipolar speakers of the past usually output the same SPL from the front and rear drivers. I was concerned how the BP8060ST would sound in an acoustically treated room, since bipolar speakers, more than other types of speakers, use the room walls to create their uniquely deep soundstages. My concerns weren’t warranted -- I tried them with and without the Primacoustic treatments in place, and they sounded better with the London 10. I found they sounded best with the Control Columns mounted on the front wall placed so that the output from the speakers’ rear drivers would partially hit the front wall and partially hit the Columns. With this placement, the BP8060STs weren’t lacking in soundstage depth, and the imaging was even better. When I listened to Amber Rubarth’s Sessions from the 17th Ward (24/96 FLAC, Chesky/HDtracks), the BP8060STs were able to capture the ambiance of the recording session behind Rubarth’s delicate, beautiful voice, which imaged solidly between the two main speakers.
Performance with movies
With movies, the overall improvement with the Primacoustic London 10 kit installed was in aural focus. This was immediately noticeable with voices through my center-channel: Dialogue intelligibility was better with the kit in place. Even though the space behind my center channel wasn’t treated, the Scatter Blocks behind my listening seat had the biggest effect, reducing flutter echoes through my room. The heavy Boston accents in Gone Baby Gone can sometimes be difficult for a Canadian to understand. I can’t say I understood every one of Amy Ryan’s lines, but the London 10 certainly helped me understand most of what she said.
With seven to 11 speakers aimed forward, sideways, and backward in a modern home theater, there are a lot of sounds reflecting off the room’s walls, ceiling, and floor. The London 10 helped immensely with taming the reflections in the room, cutting down on the ringing and letting the soundfields recorded on my Blu-rays come through. This was apparent when I watched Hugo; the film’s many different atmospheres were represented, such as the large, reverberant space of the train station and a smaller, more intimate living room. The surround envelopment was stronger and more realistic between each of my speakers with the acoustic treatments in place. Nor did the London 10 negatively affect discrete sounds, such as the train whistle to the far right side of the soundfield in chapter 4. This effect was even more palpable with the Primacoustic kit in place.
I have some older DVDs, recorded in Dolby Digital, that can sound screechy and unpleasant -- such as the original Star Wars. The London 10 made these movies more tolerable by reducing the high-frequency energy in my room. With explosions and other effects containing deep bass, the London 10 wasn’t effective at leveling the bass peaks and valleys, but this is only to be expected -- it wasn’t designed to do so.
I’ve made many changes to my home-theater system over the past year, all of them costing more than the $499.99 Primacoustic London 10. These have included a new power amplifier, a new processor, new speakers, and a new Blu-ray player. Outside of the speaker upgrade, installing the Primacoustic London 10 made the most dramatic difference in my room’s sound. The clarity and focus were improved immensely by reducing flutter echoes and absorbing excess wall reflections. The sound in my room is now so much better that there’s no way this kit is going back to Primacoustic. If you have a similar man cave with mostly bare walls and are looking to improve its sound, I urge you to give one of Primacoustic’s London kits a try before you upgrade your electronics. I’d bet it would make that upgrade unnecessary.
. . . Vince Hanada
- Preamplifier-processor -- Integra DHC-80.3
- Amplifier -- Integra DTA-70.1
- Speakers -- Definitive Technology (all): BP8060ST mains, CS8060HD center channel, Mythos Gem surrounds; ProCinema1000 home-theater package
- Sources -- Oppo BDP-95 Blu-ray player, Cambridge Audio Stream Magic 6
- Cables -- Analysis Plus Blue Oval in-wall speaker cable and Super Sub interconnects
Primacoustic London 10 Room Acoustic Kit
Price: $499.99 USD.
Warranty: 30 days parts and labor.
1588 Kebet Way
Port Coquitlam, British Columbia V3C 5M5
Phone: (604) 942-1001
Fax (604) 942-1010