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Positive Feedback ISSUE 2
august/september 2002


echo busters

Acoustical Room Treatments

as reviewed by Dave Clark, Francisco Duran, and Victor Chavira


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Bass Busters





Reimer Wind River.

Clayton Audio M70 monoblock amplifiers. E.A.R. 834P phono stage. Blue Circle BC3 preamp w/Amperex BB tubes, and BCG3.1 power supply.
Taddeo Digital Antidote Two and the HRS unit.

EAD T1000 transport and 1000 Series II DAC with Audient Technologies’ Tactic and Audit, Nordost Moonglo digital cable. Linn Axiss turntable with K9 cartridge and Basik Plus arm.

Nordost Blue Heaven and SPM interconnects, and SPM or Hovland Nine Line bi-wired speaker cables. Sahuaro, Blue Circle, Custom House, and Clayton Audio AC cables.

Homebrewed ac conditioner for sources and the Coherent Systems Electraclear EAU-1 parallel conditioner. Dedicated 15 amp ac circuit for sources and 20 amp ac circuit for amplifiers. Mondo racks, BDR cones and board, DH cones, Vibrapods, various hard woods, etc. And a bottle of Rancho Sisquoc Merlot.


 one.jpg (6551 bytes)If you are not familiar with Echo Busters, they make several products, of which Echo Busters and Bass Busters are the ones I am reviewing here. The Echo Buster is a panel designed to absorb echoes or reflected sounds over a relatively wide frequency range, from about 125Hz to approximately 8kHz. The quarter-round Bass Busters act as Heimholtz resonators to address standing bass waves. Both are covered in cloth available in various muted colors, and are not unattractive. They look considerably better than the Room Tunes we had been using prior to their arrival. Whether you need products like these is a function of several parameters. Is your room easily excited by standing waves? That is, does the room have an echoey sound, as heard when you are talking or clapping your hands? Rooms can be lively or relatively dead. Which is better is a matter of what your speakers may demand and your musical preference. Too much reverberant energy, though, can cause listener fatigue and poor imaging, and wreak tonal havoc on your music. Too dead a room can suck the life out of your music, making everything dull and boring as well as affecting the frequency response. It is best to attain some happy medium.

Before you do anything, it is best to lay down a good foundation for a sonically decent room. Make sure that your speakers are in their optimum positions, as far out into the room and away from side walls as is practical, and toed so that you get the best imaging without forgoing a deep and wide soundstage. The idea is to place the speakers where the bass and lower midrange sounds the smoothest, neither too lean nor too full and boomy. Positioning them away from side and rear walls means more direct and less reflected sound. You hear more of the speaker and less of the room. Not to be overlooked is making sure the speakers are level, with the drivers firing at the listener rather than over their head or at their feet. There are several in-depth articles available on setting up speakers. Try the Cardas Golden Ratio or the method suggested by Immedia. Both are excellent starting points.

Even with the speakers in acceptable locations, the room will still affect the sound. Carpet and drapes go a long way in helping, as does furniture and other items. Plants, bookcases, record and CD cabinets, tables, etc. will help to break up the sound bouncing around the room. Try placing these in corners and along walls that are next to or behind the speakers. While this will help, the corners will still load bass frequencies and the walls will still reflect sound, and this is where the Echo Buster products come in. I have heard rooms in which the Echo Busters made a major improvement. In my room, with two Bass Busters in the corners behind the speakers and two Echo Busters a third of the way up the wall, also behind the speakers, I hear a greater sense of the ebb and flow of the musical line due to less smearing. Deeper, faster and cleaner bass, with an increase in slam and drive due to a decrease in bass standing waves. Cleaner, tighter images that are more dimensional and palpable. Greater articulation and overall improvement in transparency from the midrange through the treble. Fortunately, I am blessed with a decent room, so these are not night and day differences, though I did end up buying these to replace the Room Tunes and some homebrewed MDF/concrete corner plant stands I had been using. The Echo Buster products just made things better. Your mileage will vary, depending on what you start with.

Are they worth the money? As a final step in an audiophile system, they are a must. We spend countless hours and dollars buying this or that, tweaking here and there, seldom paying attention to the room, which may have the greatest effect on what we hear. The Echo Busters take that step, and work as promised. Dave Clark





ProAc Response 2s.

Reference Line Preeminence IA passive. Monarchy Sm70 amplifier.

EAD DSP 1000 III DAC, Pioneer DP 54 as a transport, and Musical Concepts DV414 DVD player.

Kimber Hero interconnects, Acrotec 1050 speaker cables, and LAT digital cable.

Panamax PLC.


two.jpg (6646 bytes)So, you have read reviews of room treatments, and what you have read is mostly positive, but you still haven’t bothered to do anything about that bass node or the slap echo in your listening room. Me too, but what do you think I did? I made my own room treatments. Although they certainly were cheaper than buying commercial products, they were something of a pain to put together, and now I know that they don’t work as well as the gen-u-ine items. Although my homemade treatments did work to a degree, and my wife thought they looked okay, the bass still loaded up in one corner of my room and I still had slap echo by my sliding glass door. Time passed, and a few weeks after CES I found out that Dave Clark, our resident tweaker, had brought back a slew of room acoustic devices from Echo Busters.

I ended up with three Double Busters, which are designed with both diffusive and absorptive materials, two Echo Busters, which are absorption-only panels, and lastly, two Bass Busters to handle the lower frequencies. According to the info sheet, Bass Busters absorb sound in the critical 6 to 225 Hz frequency range. When bass-heavy music is played, the Bass Busters’ resonant frequency is excited and they vibrate sympathetically, wicking off some of the bass energy from the room. I have to admit that it was fun placing the panels in the room at various positions and listening to the changes. It was sure easier than changing interconnects or lifting heavy speakers and amps.

I tried the Echo Busters first. Their recommended placement is the center of the wall behind the speakers and at the side walls, where the first sound reflection hits. After experimenting with various positions, I found that this was where the Echo Busters sounded best. It is also where I had my homemade jobs. With the Echo Busters, there was less smearing of detail. The music was a little more solidly placed in space, and the trailing edges of the music were more intact and less distorted. The slap echo that I mentioned earlier was reduced a great deal. It was nice to sit at my listening seat and not hear an echo of the music behind and to the left of me. At the same time, however, the Echo Busters shaved a little too much sparkle from the top end, so I switched to the Double Busters. Since the Double Busters both absorb and reflect, I wanted to see if they would work better. Sure enough, the sparkle was restored and the slap echo was still tamed. Also, using one Echo Buster in the middle of the back wall and off the ground by a few feet really solidified the imaging of my system.

With the addition of the Bass Busters, which are four feet high and shaped to be placed in a corner, I could address the low end of the music. What I heard with the Bass Busters was immediate and positive. Bass notes now sounded more defined and less smeared. Boy, what you don’t know ‘til you know it! The bass was not being reduced. Instead, it was cleaned up and sounded smoother. From the mid-bass to the midrange, images were more locked in place (this was with the other panels taken out).

We all know that our listening rooms can be problematic. There are a number of products that can help tame a bad-sounding room. The Echo Buster products help, and they are aesthetically pleasing, affordable, and work very well. I bought a pair of the Bass Busters and soon hope to buy some Double and Echo Busters. Francisco Duran

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Double Busters





Magneplanar .5.

Sonic Frontiers Anthem 1 amplifier.

Audio Electronics CD1 player.

Kimber PBJ interconnects and Tara Labs RSC Prime Bi-wire speaker cable.


three.jpg (8484 bytes)Question: What’s the quickest and easiest way to improve your sound? Align your speakers to the North Pole? Rub Vitamin E on your CDs? What about room treatments? You know, those fancy pillows and panels that attenuate and absorb detrimental room reflections. Well, I’ve tried the North Pole thing and the Vitamin E thing, and neither made as great an improvement as hanging one Echo Buster panel.

Echo Buster panels are 18" x 48" frames covered in decor-friendly fabrics. The frames contain either slats for diffusing sound, soft wadding for attenuating, or, in the case of the Double Busters, both. Magnepan users often struggle with the concept of room treatments. We like the idea of sound bouncing all over the place. However, just as in life, too much of a good thing is definitely bad. This was true of the wall behind my speakers, home to three lovely glass-framed lithographs of Hispanic art. Each is about two feet by three feet, so I had about 18 square feet of reflective glass directly behind my speakers.

Thank goodness the Double Buster came along, because I had become very tired of taking down the pictures every time I listened to music. Replacing the central picture with a Double Buster transformed my room. The Double Buster remedied the smearing effects of slap-back echo that I had accepted as part of the dipole experience. Images became more focused and detailed. The soundspace sounded more defined. Center image, already a Magneplanar hallmark, was even more tangible. Needless to say, the Double Buster is now indispensable, and one lithograph has found a new wall to decorate. Double Busters are enthusiastically recommended. If you’re a panel speaker owner, they’re a must. Victor Chavira

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Echo Busters




Retail prices vary based on size.
Bass Busters: $429 to $689 (pair)
Echo Busters: $105 to $235 (each)
Double Busters: $150 to $345 (each)

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