[Danberg]

Where I do my music listening is a "formal living room" , per my wife.  She is not willing for me to permanently hang any treatments on the walls.  I have read information offered in the "Acoustic Circle" regarding the differences that acoustic treatments make in a room.  However, I have never experimented with any, mainly to keep my wife happy.

Over the years I have experimented with changes in equipment, cables, tweeks, etc. to achieve the "sound" that I find pleasing.  Unfortunately, I have never been close to being fully satisfied, regardless of the combinations of the above that I changed.

My wife went to visit a sister for several weeks and while she was gone I did do rudimentary experimentation, simply by diagonally hanging floor to ceiling thick bath towels in the two corners of the room directly behind my speakers.  Additionally, I hung a large towel on the wall, centered between the two speakers.  Also, I hung a couple of towels on the wall directly behind me, at my listening position.  I simply couldn't believe the sonic difference these made.

The fatiguing high frequency irritating sound that I simply could not remove no mater what combination of tweeks, equipment, cabling, etc. disappeared.  What I had put up with over the last 15 years was dramatically improved.  I was stunned.  Additionally, there was a positive improvement in my systems bass response (less smeared, less one note bass, etc.).  Clapping my hands in the room now no longer produced an audible echo (which had been lasting 3/4 to 1 second, I'd guess), as it always had in the past.

I guess a description of my listening space would be helpful.  Living & dining room are attached.  The dining room is at the narrow end (13'-6") of the living room.  The other 13'-6" wall consists of a 8' wide by 5'6" high window covered with sheer drape material.  Both rooms have 8' ceilings.  Both are stud wall construction with drywall.  Both floors are carpeted wall to wall.  Living room dimension: 15'-9" x 13'-6".  Speakers are in the corners, along the 15'-9" wall.  Listening couch is directly across and against the opposite 15'-9" wall.  The 13'-6" end of the living room opens up to our 11'-9" x 11'-9" dining room.  They are separated by a 3' tall 1/2 wall.

The speakers are floor standing and their  backs are approximately 12" from the back corners.

My solution to keeping my listening area as a formal living room, yet but easily  converted to an improved listening space, is by placing decorative, unobtrusive hooks in the walls, close to the ceiling, to hang some type of cloth similar to the thick terry cloth towels I experimented with, at the same locations that I hung the towels.  The cloth could be easily taken down & folded up and placed in my audio cabinet when not listening to my system.

Therefore, my question is, regarding sonic absorption.  Is there any specific type of cloth that you would recommend, or should I just use a cloth that brought me such pleasing results as with the towels?  Secondly, would a fiberfill backing (3/4" to 2") to the towel material, diagonally hung in the corners, behind the speakers (floor to ceiling), help in any way regarding the sound absorption.  Remember, I would only consider a fiberfill thickness that would allow for convenient folding / storage of the cloth material.  Would that possible 3/4" to 2" fiberfill backing make any improvement in the sonic absorption?  Would it be a waste of money & time to attempt to apply that to the cloth, for any sonic gain?

[Rob Babcock]

It's amazing, isn't it?  So many guys spend years 'chasing the dragon', blowing thousands of dollars on ICs, cables and other tweaks, and trying speaker after speaker, amp after amp...all without addressing the most important part of the playback system:  the room itself!  I'd much rather have a $2,500 audio system in a well treated room than a $25,000 rig in a very live, untreated room

What you describe is reminiscent of the (sadly now defunct) 8th Nerve Response treatments.  They incorporated a strip of rigid fiberglass (IIRC) with a reflective front and absorbtive back, enclosed in fabric.  You could certainly make something similar without too much trouble.  Acoustic treatments are generally covered with burlap or fabrics very much like it.  Burlap is a loose weave and won't reflect the sound back out like tighter weaves.

I would suggest Owens Corning 703 /705 rigid fiberglass or rock wool batts instead of terry cloth or towels; it's a much more effective absorber.    You do need to wrap the batts to make sure the glass fibres don't come out- quilt batting works well for this.  Ethan & Bryan can probably explain in more detail but thicker is better.  You want some broadband absorption that extends into the bass range but without killing all the highs; you need a fair amount of material to do this.  Obviously I realize you are looking for a compromise, and the larger & more effective the panels the less easily you'll be able to hang and remove them quickly.  I have had pretty good results with the more advanced 8th Nerve Adapt line, and that's led me to theorize that where the treatments are placed is ultimately more important than the sheer size of the treatment.  Trihedral corners are the most in need, followed by the junctions of the walls/ceilings and walls/floors.  As you've discovered, straddling the corners with some absorption makes a huge difference.

If you can do it, my suggestion would be to get some mineral wool or 'glass batts.  Cut them to whatever width you can work into you room (at least 1' wide is a good idea, wider if you can).  Make them at least 2" thick, either by using one piece or stacking two x 1" pieces. Wrap the batts with some quilt batting which you can buy very cheaply at Wal-Mart. Cut a strip of plastic (either a heavy Hefty bag or a heavy plastic dropcloth like painters use) the exact size of the batts and lay it on top.  Then wrap the whole thing with your choice of cloth.  Velour works reasonably well, but Burlap or other loose cotton weave is ideal.  Best would be to stitch it, making something akin to a large sock, but you can probably glue it if you need to.  A frame improves the trap but makes it heavier and less portable, and it will work well without it.  One nice touch is a small strip of wood inside the top back like a coathanger to keep it hanging straight without sagging.

Good luck your designs!

[lonewolfny42]

This was a nice DIY project thread by PeteG....

http://www.audiocircle.com/index.php?topic=17771.msg155457#msg155457

And the finished look....very nice.

[oneinthepipe]

You can use stand-mounted panels that can be easily moved both for musical and storage purposes, and these panels will give you much higher broadband absorption coefficients and, concomitantly, much better sound than bath towels and fiberfill.  You will be amazed by the improvement.  I promise.  Seriously.  Treating your room is as important, if not more important, that buying a better pair of speakers.   And you never know, your wife might mind the room treatment  too much, especially if she also likes music and you buy her that three stone ring or take her on that cruise that she always wanted to take, and maybe you won't need to move them that frequently.  (One of my wife's law clerks visited our home and thought that the panels hanging from the walls and ceiling comprised an art display.  She wanted some for her room, and when I asked her what type of system she had, she appeared very confused.)

Both GIK and Real Traps produce several products that are stand-mountable, and I pasted a couple of links below that have images of the stands.  Even if you don't use stand mounted panels, you can merely lean the panels against a wall.  If you have to forgo the ceiling panels, use that to show you wife that you are amenable to compromise. 

The difference in the sound with room treatments is enormous.  Whether you DIY or purchase from a vendor here, these will be some of the best audio dollars that you ever spend, and the acoustic treatments will improve every system that you ever own.  Even though I have thirty-five years experience with audio (no one here would ever believe that for a second), I was an acoustic treatment neophyte when the good people on the AVA forum told me that my room was messed up and I didn't need a new pair of speakers (but I bought those anyway, and I bought a pair of Salk HT2-TL.  Whoa hoa!).  One last piece of advice.  Do it right the first time.  Don't install panels that are too thin, then later realize that your treatments are insufficient or imbalanced.  Buy or build the 4" thick panels and 6" thick panels now, so you don't need to start over later, which I did at much greater total expense.  "When you buy quality, you cry only once."  Good luck.  You will be happy.

http://www.gikacoustics.com/products.html

http://www.realtraps.com/p_stand.htm

[Ethan Winer]

Is there any specific type of cloth that you would recommend, or should I just use a cloth that brought me such pleasing results as with the towels?

As Rob said, you really should consider more suitable materials. A towel might help a little, but in the end it's not a good solution. The proplem with thin materials is they absorb only high frequencies, leaving the bass boomy and ill-defined. Treating only high frequencies is in some ways worse than no treatment at all, because it makes the bass problems even more pronounced by comparison.

If you are unable to treat your room permanently, you can buy or build traps with stands to be portable. Then to can bring them out of the closet for serious listening, and put them away when company visits.

--Ethan

[Danberg]

Is there any specific type of cloth that you would recommend, or should I just use a cloth that brought me such pleasing results as with the towels?

As Rob said, you really should consider more suitable materials. A towel might help a little, but in the end it's not a good solution. The problem with thin materials is they absorb only high frequencies, leaving the bass boomy and ill-defined. Treating only high frequencies is in some ways worse than no treatment at all, because it makes the bass problems even more pronounced by comparison.

If you are unable to treat your room permanently, you can buy or build traps with stands to be portable. Then to can bring them out of the closet for serious listening, and put them away when company visits.

--Ethan

After getting such great responses I guess I should be more definitive in my question.  I have a real concern about using fiberglass as an absorber.  Maybe an irrational fear, but the thought of fiberglass fibers coming loose (or only being held in place by porous cloth) and in a living space, is a real concern of mine.

Will 4" of poly-fil accomplish the same thing as the fiberglass regarding absorption?  Any tech wizards out there?

[JoshK]

You might look into Bonded Logic.

http://www.bondedlogic.com/ultratouch-cotton.htm

[bpape]

Polyfill isn't going to have the density you'd like to have, much less be something that you could easily cover and make look nice.  I have access to some 3lb density acoustical cotton that does an excellent job, is fire and smoke rated, comes in various colors, is LEED certified 'green', and actually performs slightly better in the bottom end inch for inch than 703.

Bryan

[Ethan Winer]

Maybe an irrational fear, but the thought of fiberglass fibers coming loose (or only being held in place by porous cloth) and in a living space, is a real concern of mine.

As Josh and Bryan already told you, cotton is a suitable substitute for rigid fiberglass. But it's more difficult to work with when making portable bass traps because it's very floppy. Further, fiberglass is not dangerous. See this:

American Lung Association

I've owned and spent much time in recording studios with simple burlap over rigid fiberglass since the 1970s and I'm still alive.

--Ethan

[Danberg]

Thanks Ethan for that link to the American Lung Association.  I appears I have had an irrational fear of fiberglass for years! 

I appreciate everyone's help!  Now onward with my sound absorption project! 

[oneinthepipe]

Thanks Ethan for that link to the American Lung Association.  I appears I have had an irrational fear of fiberglass for years! 

Don't breathe a lot of MDF dust, however.