DIY Tube Traps

[jmierzur]

With the completion of my basement (which included a dedicated HT room) almost three years ago, I have been experimenting with acoustical treatment methods. I started with furniture, progressed to DIY fiberglass wall panels and have ended with constructing DIY “tube traps”. This is a quick note on my results to date.

I now have seven tube traps for my room in various states of completion. The traps were constructed using the Jon Risch method. This project was broken into several phases and has taken over two years to reach this stage due to having a one-year-old daughter and a two-year-old son.

The first phase consisted of constructing three 16” diameter x 48” tall tube traps. These were placed in three corners of the room. The forth corner has a fireplace so a larger trap was not constructed. The improvement in acoustics for this trial was encouraging enough to continue with a phase two of the project.

Phase two saw the construction of three 13” x 60” and one 13” x 72” tube traps. Two 60” tall traps are placed against the side walls one third of the distance from the front wall, also in the path of the side wall first reflection point. One 60” tall trap was placed against the left side wall one third of the distance from the rear wall (no corresponding trap was placed along the right wall as this is the start of the fireplace). The 72” tall trap was placed in the right rear corner with the fireplace.

The acoustic improvements achieved at this point are breath taking and have surpassed all expectations. I can now hear additional details in recordings I did not know were present. The dynamic range of the room/system has significantly increased. The soundstage is deeper, it now envelops you and the spatial detail has greatly improved.

At this point, I will now complete construction of the 13” diameter traps. The three 16” diameter traps will be rebuilt into two 16” x 72” traps for the front corners. I am also envisioning a phase three that will see the construction of several traps that can be used around the fireplace. The traps will be built using “pipe insulation” as per the Jon Gale method as it is called. These will be smaller in diameter as well as portable so they can be stored when not required (fire place on in winter).

With the experimentation I have completed, I can not stress the importance of treating the acoustical environment. I now realize that the room is just as, and quite possibly, more important than the reproduction system.

If anyone is interested, further information on tube traps can be found at the ASC web site. There are many documents describing the theory, benefits and placement.

Till next tweak.

[madmax]

We need pics! :)

madmax

[jmierzur]

Originally posted by madmax
We need pics! :)

madmax

The wife wanted a 35mm SLR, I wanted digital. She won this time. I would like to have taken pictures of the construction process and post these somewhere, but that might have pushed the wife over the edge. Sorry, no pics at this point.

I have an older picture we had transfered to digital in the System Showcase. This picture was taken for insurance purposes and shows the two 48" tube traps in the corners behind the subs. The wall unit has also been replaced with Sanus stands.

Edit...

Just looked at the Showcase pic; room does not have all the junk in it any more.

This is a site that has good pics of the Gale method.

[jmierzur]

Originally posted by madmax
We need pics! :)

madmax

As requested, I updated the System Showcase with pics from a digital camera I borrowed.

Edit: The 13" tube traps in the pictures have a temp covering of the thinnest weed barrier I could find. I will be making 'socks' using black speaker grill cloth to slide over the traps in the near future. Wood caps will then be attached to the ends.

[jmierzur]

I now have 11 tube traps for the HT room in various states of completion. Four are built using the “Risch” fabrication method, while the remaining seven use the “Gale” fabrication method.

From the front of the room proceeding to the rear along the left and right side walls, the tube traps I have include:


16” x 72” (L+R front corners; Gale method)
11” x 60” (L+R positioned at ¼ room length; Gale method)
13” x 60” (L+R positioned at ½ room length; Risch method)
11” x 60” (L+R positioned at ¾ room length; Gale method)
13” x 72” (left rear corner; Risch method), 13” x 60” (right rear corner; Risch method)
12” x 72” (rear center; Gale method)


The four “Risch” tube traps can permanently reside in the HT room, but still require speaker cloth to replace landscape fabric as a cover and decorative end caps. The seven new “Gale” tube traps are not ready for permanent residence within the room. They still require polyester batting, half side of diffusion material (limp plastic) and outer cover of speaker cloth with decorative end caps. However, I did conduct a trial listening evaluation last night to determine if this will be the final configuration I will proceed with.

Once all the traps were in place, I noticed the reverberation time was remarkably reduced. The comments I noted in my initial post were further improved on, especially the depth of the soundstage. In addition, the system sounded “different” from what I am accustomed to hearing. It may be that having the seven incomplete traps caused the acoustic environment to be too dead.

But I have determined that this will be the final configuration and will proceed to complete the seven traps for permanent residence within the room. Once the diffusion material is in place, I will be able to tune the room acoustics to my tastes by rotating the traps to expose or conceal the diffusion material.

I will post a conclusion to this saga at a future date when the traps have been completed.

[Meeks32]

Question, these arent the same as "bass traps" are they? Do you think it would be worth the time to build 4 tall ones to go at each corner from floor to ceiling? I live with 3 roommates that dont quite share my same love for audio so I doubt they would want them all over the walls like that guy has.

[jmierzur]

If the “bass traps” you are referring to are cylindrical in shape, then the “tube traps” I mention are the same beast. If the “bass traps” you are referring to are panels, then no, we are referring to two different items with the same ultimate purpose.

Technically speaking, tube traps are broad band absorbers. Bass is one of the effective frequency bands of the design. The larger the diameter, the lower the starting effective frequency.

If I was to apply a minimum configuration of tube traps within a room, I would place three along the rear wall; one in each corner and one in the center. Next would be two traps at the mid point of the side walls…

Yes, it would be worth the time and effort to construct or buy any room treatment items. I should add that there are also DIY designs for wall mounted broad band panels. These would be easier to construct and might be more roommate friendly. I am required to use tube traps because if you look at my pictures in the system showcase, I do not have any placement options along the right side of the room for wall mounted items. The tube traps rest on the floor, eliminating wall placement conflicts.

[jmierzur]

We finally have a digital camera!

I posted new pictures of the room in the Showcase with all but one tube trap in place. The latest traps are "white" in color as they do not have a fabric covering. That will be the next step in the coming weeks.

[jmierzur]

With the renewed interest in dedicated listing rooms and acoustical treatments, I thought this might be a good time to update this thread. The room size is 15’ x 13’ x 8’.

I have completed sewing and have installed fabric covers for the tube traps. I am happy to report that the visual appeal of the room has greatly improved. The final step will be to sand/stain/clear-coat the caps for the traps to give them a professional presentation.

Here are some interim pictures I shot this morning that will give you an idea of what I have done for the room.

Edit

Please refer to my Showcase for pictures of the audio environment.

[RuSsMaN]

Sick man. That's my next step for the front listening room.

[jmierzur]

Sick man. That's my next step for the front listening room.

Yes, I have a lot of problems that I am starting to resolve.

[dorokusai]

Just make sure you don't overthink the whole project. You can easily overdamp a room as easily as you can tweak it.

[jmierzur]

You can say that I over thought the whole project; I ended up with about five inches of double sided printed pages after I finished researching room acoustics.

You are correct; one can over dampen a room. With tube traps, it is recommended to place one approximately every three feet around the perimeter of the room leaving the remaining walls bare. As far as my room is concerned, I have not reached that point nor will I be constructing more traps due to forces beyond my control.

The hardest part will be listening, rotating each tube trap to dial in the room acoustics and then re-listening...

[jmierzur]

The functional aspects of the 11 tube traps have been completed and have been covered with a ‘sock’ made of speaker grill fabric. The remaining tasks are the sanding, application of a clear coat finish and mounting of the decorative end caps. This will need to wait for warmer weather for the application of the clear coat finish in the garage.

After experimenting with placement options of the tube traps, I have decided on an alternate arrangement than the one initially envisioned. The final placement option is as follows:

16” x 72” (L+R front corners)
11” x 60” (front center; two channel listening only)

11” x 60” (L+R positioned at ¼ room length)
13” x 60” (L+R positioned at ½ room length)
11” x 60” (L positioned at ¾ room length)

13” x 72” (left rear corner), 13” x 60” (right rear corner)
12” x 72” (rear center)

The 11” x 60” trap destined for the right side ¾ room length will now be located at the front center position for two channel listening.

While I listen to two-channel music 95% of the time while in the room, I also enjoy watching a movie on the large screen while being immersed within the surround sound experience. Wanting the best of both two-channel and multi-channel environments, I am required to make a compromise by having a RPTV (plasma was out of budget at time of purchase) and additional multi-channel components placed between the L+R speakers.

Having the 11” x 60” tube trap located ¾ room length on the right side of the room at the outside fireplace corner yielded little improvement in the room’s overall sonic characteristics. Additionally, I do not think a tube trap is effectively utilized on a 270 degree corner.

Looking around the room, I started theorizing alternate placement scenarios for the rogue tube trap. My initial thought was it would be most effective along the rear wall of the room. But placing the trap along this wall would require construction of an additional 11” x 60” trap for placement in the corresponding opposite location. As I have permanently closed my tube trap acoustical treatments construction company, I am not able to build any additional tube traps. Reflecting on the fact that most of my time I am listening to two-channel music, I tried placing the rogue tube trap centered between the L+R speakers.

The changes to the acoustical properties of the room were immediately apparent. The soundstage with 10 of the 11 tube traps positioned as pictured in a prior post is both wide (enveloping) and fairly deep with very good layering. All frequencies are well articulated and have precise spatial locations. I had hoped that the soundstage would have been deeper with all the treatment in place but knew the components between the speakers would be a limiting factor. With the tube trap in place between the speakers, the sound stage depth deepened further with more layering.

Tube traps have dual characteristics; one half is a broad band frequency absorber with the other half absorbing the lower frequencies and diffusing (reflecting) high frequencies. After experimenting with these dual characteristics, I determined having the high frequency diffusing side facing the listing room produced the results I most enjoyed.

As a result of these placement changes, I do not have to construct another tube trap for the room. Having lost the right side ¾ room length tube trap to the front center position, I may need to construct another type of acoustic treatment for the protruding fire place corner. At this point, I think it’s safe to say that I can now close this DIY Tube Trap thread. It has been interesting to learn about the acoustical properties of rooms and the methods of controlling these characteristics.

Overall, this has been a very rewarding project; there have been many high points as well as low points during the project life cycle. At many times throughout the construction process, I wondered if it was worth the effort to construct this type of acoustical treatment. Preliminary results continued my desire to complete the project. Component upgrades during the project provided additional fuel to the fire to reach project completion.

If you are able, I highly recommend adding any acoustical treatment to your audio environment. This is a very important complement to your hardware that is too often ignored.


Till next tweak,


JM

[jm1]

The project has taken longer than I initially anticipated, but the tube traps have finally been completed. I think I can attribute the extra time to my reluctance of removing myself from the listening position to complete the remaining tasks.

Attached are pictures of the room with the final destinations of the traps. One front pictures depicts HT use while the other depicts two-channel listening.

The remaining task for the room is to relocate the artwork along the left side of the room and acquire a horizontal piece for placement above the side tube traps.

JM