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Rebuilding My Music Room, Part 2

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Also read: Rebuilding My Music Room, Part 1

This is the second of a 2-part article describing the process and results of rebuilding my music room. The first part described the goals I had when I started. This part will describe issues that arose during the process, the choices I made, several unexpected problems and opportunities and the final result.

Controlling Bass Response Is the Most Difficult Part of Room Acoustics. It is almost impossible to have too much bass trapping in a room. Unless you have a very unique room with “ideal” dimensions (and it’s not very easy to get ideal dimensions even when building from scratch with a big budget – witness the various symphony halls in the world that struggle to get it right), you’re going to have some bass boom unless you use a lot of trapping or work with some type of room correction. However, there are two big problems with using a lot of bass traps: 1) they can look really lousy and 2) most bass traps absorb the full range of the audio spectrum. This second problem means that you might correct for all the bass boom in the room, but end up with a room where the music sounds lifeless (try listening in an anechoic chamber and see how it sounds). Most of the reputable acoustic treatment companies that make bass traps include materials that reflect the mid and upper octaves so that the absorption is concentrated in the lower frequencies. One way to do this is to put a layer of such reflective material over part of the trap. For example, some traps have reflective material on half of the round or on 2 sides of a column trap. This allows you to turn the trap so that the reflective material faces a direction that sounds best in the room. The problem with this is that the trap still looks like a bass trap, especially if it’s a column that is fully round or squared. Some of the visual effect can be minimized by use of triangular bass traps or the creation of ceiling soffits that look more like they’re part of the room.

In the past my listening room made use of the “deadwall/live wall” model. This involves a front wall (behind the speakers) that is absorptive and a rear wall that is reflective. Of course, this doesn’t mean that you want your front wall to be totally absorptive or your rear wall to be totally reflective. Room dimensions can affect the degree of reflectiveness and absorption needed, so you have to experiment. One of the reasons that it helps to put absorptive materials, especially bass absorption, at the front wall is that the front wall generally has the greatest amount of bass energy. Bass energy tends to build up in the corners, so it is very typical to see bass traps in the four corners of the room. However, the front two corners are usually more critical than the rear corners.

After the four corners of the room are addressed, you’ll most likely get the most bang for the buck by installing bass trapping soffits on the front wall, followed by soffits on the side walls. Two advantages of soffits are (1) they tend to be a bit less visually obtrusive and (2) they don’t take up floor space. Bass trapping also works in the floor, but usually you have limitations that prevent you from having openings in the floor (things fall in), and a floor-standing “soffit” would take up too much room.

I addressed these issues in four ways: 1) I refurbished my existing bass traps and installed them as soffits; 2) I built some bass trapping into the room walls and floors; 3) I used triangular corner bass traps that employed an attractive external wood finish; and 4) I had all of the traps built and stained with one consistent design and the same stain colors.

Refurbish Existing Bass Traps and Mount Them As A Soffit. I didn’t want to simply toss the ASC bass traps I already owned, so I decided to reupholster them and use them to make a soffit for the front wall of the listening room. The simplest and cheapest way to do that was to put a new acoustically-transparent fabric over the existing fabric, and then create new endcaps that would also operate as mounting brackets. I decided that the endcaps should be wood and match the other wood in the acoustic treatments I would be installing. I was lucky enough to have a creative carpenter/handyman who built and/or stained all of the acoustic and anti-vibration treatments that are in the room, as well as the custom shelving and rack. Here are pictures of the original ASC Cube Traps, how they looked after being recovered with the acoustic fabric, and how they ended up looking after being mounted as soffits with the new endcaps. This soffit was clearly the trickiest thing to accomplish in a visually appealing manner, but I was pretty happy with the outcome. More importantly for the audiophile in me, the soffit provides significant front-to-back and floor-to-ceiling bass control without taking up any floor space.

6 Responses to Rebuilding My Music Room, Part 2


  1. Demerara says:

    The thought and detail that went into consideration of all the elements is impressive. I may have missed your comment about it if you addressed it, but do you find the bank of windows without any apparent treatment creates any issues with the sound?

    • Ed Momkus says:

      Hi Demerara – I’m so sorry that I didn’t respond months ago to your inquiry. I failed to check the comments after posting this article. Yin short, the window bank in its configuration has very minimal effect of the room’s sound. It is well above the main listening zone of the room, and in addition, I have tuning dots on the fixed glass panes, and they have always worked for me to control glass reflections. However, I would never want a listening room to have regular windows or tall windows without having acoustic curtains in place. — Ed Momkus

  2. Ostap Nakoneczny says:

    I am also in the process of building a dedicated A/V room in my basement. I also have been thinking of the installing built- in bass traps. Can the traps be initially tuned to a particular frequency by first varying the size of the cavity along with the size of the opening in the wall? Would the damping material then be used to fine tune the trap? I’m starting with a decoupled room.

    • Ed Momkus says:

      Hi Ostap – I’m sorry about the delay in responding to your inquiry from when you first posted your question. I’m probably too late, but here goes. I’m not an acoustics expert by any means, but I have learned some basic principles. First, the thicker the absorptive material the more effective it will be. In my opinion, a 4 inch thickness is the MINIMUM, and 8 inches is much better. Second, the bigger the rear cavity the better – at least 12 inches in my opinion. This is already unacceptable in many rooms. There is a mathematical formula you can look up that calculates the ideal cavity size, and the size is huge – you would in effect have to build a room-within-a-room and lose four or more feet on every wall, and that doesn’t address floor-to-ceiling issues. Note that, conceptually, the sound waves pass through the absorptive material once, dissipate further as they traverse the cavity, hit the rear of the cavity and bounce back, then pass through the absorptive material a second time before returning into the open room. The lowest notes need more thickness/cavity size, so in this sense you can “tune” the bass tap, but really you’re just making it more effective in absorbing the entire bass frequency range. Remember that most of the available absorptive materials absorb full-spectrum (including everything above the bass range), so you also need some reflective material on the front to reflect minds and highs. Otherwise your room will be too “dead”. (Of course, this material must allow the bass to pass through.)– Ed

  3. Paul says:

    Really informative article. I have a question about the Legacy Wavelet and its ADC. Since I listen equally to digital and analog (VPI Classic 3, TriPlanar Mk VII Ultimate arm, Dynavector XV-1s cartridge, and Pass XP-15 phono), it’s important that the ADC is up to the task. Will the Wavelet be equally good for both formats?

    I’m also intrigued by your custom Jatoba rack. Where did you source the Jatoba shelves?

    • Ed Momkus says:

      Hi Paul,

      I have to first apologize for the delay in responding. I just submitted my review of the Wavelet, and it should be published soon. In a nutshell it is highly recommended.

      I need some clarification on your question about the “ADC”. I’m not aware of any Analog-to-Digital conversion done by the Wavelet. It has its own DAC, but a digital outboard device that has its own built-in DAC can be plugged into the analog inputs, and analog sources just get plugged in the analog inputs the same way.

      If your question is how the Wavelet sounds when using the analog inputs, it’s very good. I did not specifically do a critical-listening comparison of vinyl sources, but I did listen to digital devices that had their own DACs, and the sound of their analog output into the Wavelet’s analog inputs was quite good – IMO equally to very high quality analog preamps.

      As for the custom Jatoba racks, I had a carpenter select and make the shelves. He sourced the Jatoba slabs from a well-known local commercial lumber distributor – Oak Hardwood Lumber in Lombard IL.

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