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In Reply to: RE: Tube Bass Traps. posted by rosendds@frontiernet.net on October 20, 2016 at 06:28:33
I built 67 of these for my sound room. Forget the brand, but it was simiar to Knauf. Believe the place was Pacific Insulation here in Portland. ASC is 2 hours away, in Eugene. The ware-houseman said they had "a guy" from Eugene that bought the same stuff. I didn't fill them with anything, but I did put a circle of fiberboard 1/3rd of the way inside the tube, with a 1/4" airhole in the middle. I cantered it slightly to break up resonances. The hole is for pressure equalization. Used drummel-cut 1/2 inch pressboard for the ends, liquid nails as adhesive. My recommendations:
* experiment with the thickness of plastic for diffusion on 1/2
* A 4 ft height is much more useful=1 unit would be over ear height
* They hold up for years, but the chicken wire ASC uses adds stability
* Find a shop that will cut the circles for you ! (Pain to do by hand)
They make a huge difference in bass and imaging. Map out your room nodes and consider the lowest frequency that your speakers put out and ear can hear. I initially built 2 helmoltz resonators to address my 22hz fundamental. My Maggie6L's don't go much below 60hz and my ears lose 40 and below. Oops.
"I see sound waves"
Follow Ups:
Is this "blueprint" based on taking an ASC tube apart?
Hey there. One thing I can't quite visualize here is how to get the material attached? Staple to the top of the wood discs? But seems like that would give a real unfinished appearance. Also is there a preferred material for this that would allow the sound to pass thru ?
Thanks tim
Check out my picture, above. I glued the end circles to the fiberglass tube. I then stapled the 1/2 plastic diffusion material, then the speaker cloth covering. The white pvc (patio-door slats) on the top, sticking above the top of the tube about 1 inch. I also put PVC strips on the bottom, flush with the floor. These covered up all the staples to give a finished look. Of course, the tubes with the bottom pvc could only be used as bottoms: they wouldn't fit inside the pvc on the "tops".
"I see sound waves"
The DIY instructions on the web advises covering 1/2 of the fiberglass tube with 2ml plastic using staples into the fiberglass.I used spray adhesive on 4 of the 3' traps that I built.On the last two traps,I removed 1/2 of the coated foil rather than removing all of it & going back with 2ml plastic.I found that the coated foil works well as a difusser.My next step will be to cover the traps with muslin or other inexpensive fabric.
I saw the 'remove half of the foil' - and either place it in front for diffusion - or back for absorption..... Trying to figure if the 2mil plastic would have any detrimental effects?
Btw - thanks .... I didn't think of spray adhesive... I have also seen this seam glue .... which could work as well....
It seems like creating the round cutouts would be the most difficult task here....
They say to remove all of the foil and replace 1/2 of it with the plastic.I did not experiment with the units that I removed all of the foil and did the 1/2 plastic,but the unit that I left 1/2 of the foil certainly acted as a diffuser when the foil side faced out into the room.
I experimented with a variety of clear plastic thicknesses for the diffusion. Opted for a thinner one than the 2 mil, but I don't recall what I settled on. Have to disagree with leaving the foil on the fiberglass tubes: it's way too thick. The original tube traps use a clear plastic with a number of different holes in it: presumably to absorb / diffuse different frequencies. On my DIY, I used the clear plastic as a solid peace on 1/2 side of the tube.Stapled it to the presseboard-circle ends. It's okay if it flops around the length of the tube. You still want the bass pressure waves to get to the fiberglass. I bought speaker fabric from Joannes fabrics:4 ft wide. Rolled the tube slowly as I stapled the fabric to the pressboard circles on each end. Once the fabric totally encircled the tube, I folded the final 2-3 inches extra fabric under itself, then used fabric-glue along the length to seal it. I ensured that the glued seam was on the NON-diffuse wide of the tube. Also place a brass upholstery tack in the fiberboard circle, on the side of the diffusor (opposite the seam-side). This was done, AFTER affixing the white PVC end to the top only: used with upholstery tacks for that. Remember to leave about 1 inch of the PVC strips extended on the top of the tube, to hold a 2nd tube stacked on top.
"I see sound waves"
Good work making the tube traps.Cutting the circles is a PITA huh?How do you know that the ASC traps have perforations in the diffusing plastic layer?I have two 3' 20" traps stacked in the rt corner of my front wall that I left 1/2 of the foil on.I have 3/4 of the foil layer facing into the room.I know that the foil is thick,but the room sounds nice,vocals are right in the center,bass well defined & less bloat.I have two more stacked in the corners of the rear wall absorptive side out.I'm only using one stack on the front wall rt.corner since the wall rounds on the left & there is a utility room door.I'm thinking that the room sucks up some bass.
I have Qty 6 of the 16 inch ASC tube traps. I discovered the chicken wire (hardware cloth) and the plastic diffusor when I took one apart. The holes are not perforations. They are actually 'random' holes from 1 inch to about 4 inches in diameter. I suspect that they create a more random diffusion because the hole diameters would expose different wavelengths to the absorptive fiberglass underneath. On my DIY units a used a solid piece of plastic to cover 1/2 of the unit. Works well.
"I see sound waves"
Wow,67 is a lot of tube traps! did you join 36" segments into a longer tube,or did you put end caps on each 36" segments and stack them?I'm thinking that making 36" segments would make moving them easier.
I made them just as the fiberglass 'pipe insulation' came: in 36 inch sections. I then purchased some replacement PVC louvers from Lowes, made for vertical patio- door mini-blinds. These flexible plastic pieces were about 3 inches wide by 6-7ft tall. I affixed (staples) the white PVC encircling the top of each tube. I left half of the top portion (1.5 inches) raised above the top of the tube. When I stack two tubes, the upper tube fits into the PVC circle. Works well and is easy to move. Even two units together can be "hug-lifted" to place in another area.
Here's a picture. The gray tubes are real ASC tube traps. The others are mine. You can see how the whit PVC holds the top tube in place. I placed a brass thumbtack to show which side has the plastic diffusor on it. BTW : the diffusors work great ! But the ASC models are much better, but I couldn't afford more than 6 of them. Good luck !
"I see sound waves"
If this makes any sense. Here is a picture of a "map" I created of the tube traps. Arrows= the direction of the diffusors. It's modeled after the plans published by Peter Moncrieff http://www.acousticsciences.com/media/reviews/iar-optimizing-asc-tube-traps
"I see sound waves"
I have had ASC tube traps for 20 years and I couldn't be happier
with the results. Peter Moncrief convinced me about tube traps
and in my opinion was the best reviewer of audio around.
My room has 36 tube traps and other diffusors, as well.
Peter also convinced me of the Rotary Subwoofer!
Nice job and great room mapping !
"I see sound waves"
Super nice listening room!I'm trying to be satisfied with my six 3' 20" traps for now.I have all three 6' stacked traps on the rear wall with two in the corners & one in the center.
awesome thread. I love seeing all the effort of people building those rooms. Reminds me that I need to make more traps. I used the chicken wire and roxul method and just made 2. I couldn't imagine making 60+ of these! The cylindrical insulation would speed things up considerably though.
Making the tubes from flat panels must add a lot of work to the process.
Yup!
Can't figure out how to get more than 1 pic with my phone...
Nt
Nice set up Watts.Did you place traps in the corners of the back wall as well?Is the diffuser on the front wall DIY?
I have a couple of flat panels on the back walls; and a carpet. I should have more tube traps; like I said I need to make some more. The round insulation is what I will try next time. I want to make some triangular corner traps also. This room is 10.5 x 19.5 x 7, and with 3.6's and Mcintosh amps there is no lack of bass!
DIY RPG diffuser, actually 2 of them on top of each other, not sure what colour to paint it, so it remains primer red until I do. It is not random, each piece of wood is placed in a specific orientation according to a mathematical formula as researched by the BBC papers. This is not the source I remember seeing, but it looks the same:
http://audioundone.com/do-it-yourself-acoustical-treatments
Here is a closer picture of it
I might as well include a shot of the back of the speaker while I have the camera going.
I used Manville pipe insulation 20' which worked well.Nice job on the diffusors.In Jim Smith's 'Get Better Sound' book,he advises not placing the electronics between the speakers,but rather someplace on one of the side walls about 1/2 the distance between the speakers & the listening position.That isn't always possible,but you may want to consider it.
I have read something like that, but I think you don't want a huge piece of furniture taking up the space between the speakers, rather than the electronics themselves. Besides, at every hi-fi show this is exactly what they do; and they are attempting their best to impress others with the kit:
nt
I found that you can use a rack or anything else as a block to early reflections from the center front wall and center placed rack You place your rack or pile of junk ahead of the speakers.
I have a pile of CDs on top of a cart with equipment materials and audio rags and the vandy 2C - reaches higher than the listening seat and blocks some mid/tweeter output and early reflections. Improves imaging and detail vs. moving the cart and box speakers out of the way.
I am considering moving the racks to the middle ahead of the speakers.
I'm not sure what difference not having the rack between the speakers really makes,but I can tell you that adding bass traps took my system to a new level.The bass is more distinct with much less boom & hang.I think that the mid range is more articulate as well.
Agree on the bass traps and diffusion. Unfortunately for me the corners are occupied by other items that can't be moved (small closet and the dedicated AC).
As to the normal rack placement behind the speakers - it creates early backwave reflections from the face plates of the equipment that are really difficult to get rid of. People do this in order to cut down on the length of speaker or line level interconnect. I usually suggest people use a fake ficus or equivalent to diffuse the backwave before it hits the racks. For some people it is possible to get the dipole null aimed at the racks. Others have used their TV slightly ahead of the speakers to block the center reflections. The adjustment should result in pulling the center image forwards to where it aligns with the rest of the soundstage.
nt
Wow.Your listening room is a study in acoustical engineering. Just having 6 DIY 20" tube traps has made a big difference in the low base articulation in my room.I'm thinking that your listening room must sound very nice.Thanks for the information on the construction of ASC traps and the link to their set up articles.I may decide to build more traps after reading some of the articles.
Nice work on the tube traps.The PVC blind strips make for a nice finished look.Each 36" unit that you made has a wooden end cap on each end even when stacked with the PVC strips?How thick was the plastic sheeting that you covered 1/2 of the tubes with for diffusion?
The ends are made from 1/2" pressboard= low resonance, many speakers are made of this (don't get it wet!). The white PVC is attached with white upholstery tacks to the outside of this circle of pressboard, so the bottom of another trap (with no PVC on the bottom) fits neatly into it. NOTE: I cut these circles by hand with a drummel tool and compass. This was a pain. I would pay someone with a band saw to cut these. I don't recall the thickness of the diffuse plastic, but I did experiment with about 3 sizes. It was medium-sized, if that helps. Not a tarp.
"I see sound waves"
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