Who uses room treatments?

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  • 10-14-2004, 11:54 AM
    topspeed
    Who uses room treatments?
    I'm of the belief that speakers and speaker placement/room interaction are the two most important elements for quality sound in any system, regardless of price. The latest TAS brought this to mind as it seemed like most of the issue was dedicated to room interaction and treatments. Of course, this also meant it read like an AES Journal (or at least what I'd imagine one to be like). Unfortunately, most of the corrective devices mentioned also seemed to be startlingly expensive. Is $3000 really necessary for a decent digital eq? Sheesh :rolleyes:

    Personally, I use curtains to absorb first order reflections and as my listening room (aka Living Room) is carpeted, I've never worried about reflections off the floor. The speaker drivers are not equidistant from the side and back walls and are slightly tilted in to focus the center image. I have tall, bushy plants in the corners behind the speakers but don't use bass traps or suchlike although I probably should.

    So who uses treatments and/or equalisation and what has been your experience? Good? Bad? Work in progress? What measures have you taken to maximize your speaker placement? Is WAF a big factor?
  • 10-14-2004, 02:45 PM
    Worf101
    I do use a few..
    Just drapes and hangings but they were/are strategically placed. Most of the advice for these I got from a post I did a few months ago. Folks here were most helpful.

    Da Worfster :D
  • 10-14-2004, 03:20 PM
    Lord_Magnepan
    I use room treatments to cancel "flattering echos" etc... its important since my speakers creates huge waves. Fortunatly Maggies have very little trouble with room nodes, since they act on the entire room very balanced. But my room is still "work in progress"
  • 10-15-2004, 05:08 AM
    hifimaster
    IMO, one of the most overlooked room treatments is the ceiling. It was one of the most impactful acoustic treatments in my room. It cleared up any center channel inteligibility problems and added depth to two channel listening. I use an absorptive panel at the first reflection points of the center and mains.

    James
  • 10-15-2004, 09:24 AM
    BillB
    My room is a work-in-progress. It is featured in the November issue of Home Theater Magazine in an article dealing with room acoustics.

    I've added one Michael Green RoomTune Kit that includes 4 treatments for corner/ceiling locations, 4 treatments for corners (sidewalls) meet, and 2 treatments for the wall/ceiling locations.

    I need to add two more of the wall/ceiling treatments for the front and rear walls.

    I am also going to tackle the front wall of my room. Currently I am considering 1"-1.5" thick 100% wool rugs hung on the wall.

    In the article they recommend a door of the entranceway but it's not worth it to me at this point in this house. My problem with the area was with echo coming back into the room. It's been tamed to a large extent with floor-to-ceiling drapes over the area. I used thick velvet drapes and doubled up for a total of 4 panels across the 3' area. This results in heavy pleating and has proved quite effective in reducing the echo.

    I've begun hanging pictures on all of the walls to break up the flat surfaces as well as other small objects.

    Hifimaster mentioned the ceiling and that was one of the biggest recommendations in the crtique of my system and one that I hadn't considered. While my room is a dedicated room I still have the Mrs. to deal with so searching out acceptable treatments for the ceiling will have to be done.

    Her and I are both against the addition of a second subwoofer like they recommended in this house. I'm not sure I want to delve into the EQ arena yet either.

    I've also experimented quite a bit more with placement of my front L&R speakers to tweak their response when run full-range. Tweaking my sub's phase control and level has also yielded better results when all speakers are set to small.

    I opened up my room to critique because I felt it was time for me to address this "final frontier" issue of room acoustics. I have noticed a difference with the changes made already. While I might not achieve an "A" in this room, I'll have a lot to take with me to my next house!

    Bill
  • 10-15-2004, 10:16 AM
    Sir Terrence the Terrible
    I use room treatments and eq extensively in my listening room. I have thick pad under the carpet, acoustical panels on the side walls, and a acoustical cloud(diffusion panels) on the ceiling. Whatever cannot be correct acoustically, I have three 1/3.octave eq's for each of the six channels that deal with the remaining problems electronically. At the listening position(center seat on a leather sofa) the overall frequency response deviates no more than 1.5db. To the left and right, no more than 2.5db. My room looks like a recording studio, but I don't really care. I have no wife to worry about those things.
  • 10-15-2004, 11:46 AM
    BillB
    Terrance,

    What tools did you use to calibrate your EQ? What ceiling tiles are you using?

    Bill
  • 10-15-2004, 01:56 PM
    topspeed
    Bill, your question for SirTT was exactly what I was thinking. BTW, I've never heard of treatments for the ceiling/corner juncture. What are they, triangles you stuff into the corner?

    Just so I know, what brand of room treatments are you using? Echobusters? Tube Traps? DIY? Does it matter?
  • 10-15-2004, 02:39 PM
    Sir Terrence the Terrible
    Quote:

    Originally Posted by BillB
    Terrance,

    What tools did you use to calibrate your EQ? What ceiling tiles are you using?

    Bill

    I used a B&K 4133 lab grade microphone connected to a Dell laptop with a 6.1 24/192khz sound blaster sound card, and TrueRTA software which has 1/16 octave resolution. This software has such fine resolution that I can look at frequencies note by note coming out of my system. For ceiling tiles I am using Skyline by RPG attached to the ceiling using velcro so I can move them when I change my system configuration and setup. I use a goldline multiplexer so I can use up to three microphones, and average the response at three positions simultaneously. .
  • 10-15-2004, 03:48 PM
    Woochifer
    I also got the latest issue of TAS. They've run plenty of articles about room acoustics over the past couple of years, which I definitely appreciate given how oft-ignored this topic typically is. The nice thing about dealing with room acoustics is that you can do a lot more simple DIY options with inexpensive building materials than other system upgrades. TAS is obviously highlighting the expensive high end approaches, but there are plenty of effective approaches that cost very little. My first experiments with room acoustics cost only $16 for a box of ceiling panels, and guess what, it made an audible and measureable improvement to my system. Cables, interconnects, and a whole host of other far more expensive "upgrades" can't even touch that. Widescreen Review is another good source of articles on room acoustics.

    My room has reflective surfaces everywhere and tons of slap echo, so a combination of treatments were definitely in order. The dedicated room treatments that I use in my room consist of some homemade acoustic panels and a Behringer Feedback Destroyer for subwoofer equalization.

    I started tinkering with the room acoustics using a $16 box of 2'x4' acoustic ceiling panels. I lined them up behind my main speakers and was startled at how much they tightened up the imaging and smoothed out the overall sound. (The room where I had my system before had a large picture window behind) I think it was especially beneficial with my speakers because they have rear firing ports.

    Unfortunately, just lining up the acoustic panels along the front wall looked unsightly. So, with a gluegun and some fabric, I dressed them up and hung them up on the wall using picture molding hooks (see pic below). (My wife and I installed the picture moldings so that we could also hang up pictures without having to nail or screw any hooks into the wall.)

    The Behringer Feedback Destroyer has been recommended by a lot of people on this board as a parametric equalizer for subwoofers. IMO, it's the single most crucial component you can add to your system if you use a subwoofer. Without the BFD, the bass response from my subwoofer has a pair of room-induced 10 db+ peaks that make the lows unbearably boomy. I have limited flexibility with the subwoofer placement (again, a WAF compromise), so the BFD allowed me to level out the response curve, even with less than ideal placement.

    The BFD costs $120 and people who've tried it out with main speakers say that it has audible noise and tonal abnormalities if you try using it with the midrange and highs. But, in the low frequencies, those issues don't matter and are not audible. And that's why some digital EQs cost more than others, because they were designed for maximum resolution over a wider frequency range. The $120 BFD is not the best EQ for the mains, but that doesn't matter if the main use is with the subwoofer.

    The drawback to equalization is that it's most effective at the listening position. Listening from other locations within the room, any corrections that you make might not be as effective. And that's the reasoning to go with bass traps or other room treatments, because they are equally effective at all locations within the room.

    Other things that helped the overall sound of the room included a large area rug, and moving the sofa into the room. So long as I got things like a buffet cabinet next to the subwoofer and a couple of other hollow pieces of furniture in the room, the acoustics won't be perfect, but at least it's now much better than it sounded at the outset.

    Some triangular room treatments for the room junctions are available from Eighth Nerve. I've been thinking about trying them out since I have yet to do anything with the corners.

    http://www.eighthnerve.com/response.html

    This pic shows the dressed up acoustic ceiling panels. They are suspended from the picture molding above, and I now use three of them (originally, I lined up six unmodified panels sitting on the ground along the wall, but that was too much industrial look for my wife to stomach). The gallery link has links to some of the posts that I made as the room gradually came together (look in comment #2).

    http://members.aol.com/sfwooch/images/theater10.jpg

    http://gallery.audioreview.com/showp...sort=1&cat=500
  • 10-16-2004, 08:30 AM
    BillB
    topspeed,

    The treatments I use in the corner/ceiling juncture are triangles. The Eighth Nerve products Wochifer referred to are the same thing, a copy of Michael Green's product that I use:

    http://www.michaelgreenaudio.com/catalog/test.htm

    I bought the TunePak which looks to have gone up significantly in the 6 months since I bought it. I paid $200 for it and now it's nearly double! The 8th Nerve version may be more affordable now but Michael Green's a great guy to talk to if you're interested.

    I'm trying to sort out features on my new digital camera so that I can take better pictures of my room. For a diagram, see the article in the Nov issue of Home Theater Magazine.

    Bill
  • 10-16-2004, 08:31 AM
    BillB
    Woochifer,

    Are the ceiling panels you used the same panels that would be used in a drop ceiling?

    I think I might be able to talk the wife into those (not a full drop ceiling, just a few tiles) for use on the first reflection point of the ceiling.

    Bill
  • 10-17-2004, 08:13 AM
    E-Stat
    Quote:

    Originally Posted by topspeed
    So who uses treatments and/or equalisation and what has been your experience? Good? Bad? Work in progress? What measures have you taken to maximize your speaker placement? Is WAF a big factor?

    I've been using one form of room treatment or another for decades. Currently, I use 8 bass traps placed at the corners and mid points of each wall, 3 room lenses, and two sound panels. The bass traps are primarily there for controlling bass nodes although the mid wall units help imaging. Likewise, the lenses help with imaging as well. The absorptive panels control the primary reflection from the rear of my bipolar speakers.

    As for speaker placement, I have experimented widely with differing approaches. My current arrangement is a slight variation of the golden triangle method found on the Cardas website. That results with the panels being about 8' out from the back wall. Final placement and toe in was dermined with string and a laser pointer. I used the string to assure exact placement symmetry with respect to the center listening chair. The laser locked in a consistent toe in for both speakers. What remains is completing the DIY traps. That involves removing some of the reflective coating and covering them with grey material that matches the wall panels.

    As this is a dedicated basement listening room, it is WAF free. Overall, I think it will look ok once I cover the traps. The floor wiring would probably not pass muster though.

    <img src="http://home.comcast.net/~ralphwallace/images/audio/room1004.jpg">

    rw
  • 10-18-2004, 09:50 AM
    topspeed
    Question for RW,

    I thought part of the Maggie sound came from their bipolar design? With the diffusers on the back wall combined with the corner traps and room lenses, aren't you severely limiting the bipolar effect? It seems to the layman (that'd be me ;)) that you've turned your Maggies into a monopole.

    Another question regarding the room lenses. How do they affect sound considering their placement within your rig? Are they directing sound radiating towards the side walls, coming off the back wall, both? Just curious...
  • 10-18-2004, 10:13 AM
    Feanor
    I use rear wave deflectors with my MMGs
    Quote:

    Originally Posted by topspeed
    ...So who uses treatments and/or equalisation and what has been your experience? Good? Bad? Work in progress? What measures have you taken to maximize your speaker placement? Is WAF a big factor?

    I use rear wave deflectors behind my Magneplanar speaker. They ensure that early reflections are minimized despite that fact that the MMGs are only about 2.5 feet from the wall. They are made of ordinary ceiling tile stiffened with 1x4" boards -- very cheap.

    As for WAF, my wife is pretty easy-going anyway, but the baffles are pretty much hidden by the speakers themselfves, at least from the front.

    See pictures at http://gallery.audioasylum.com/cgi/v...erImages=20428
  • 10-18-2004, 11:16 AM
    Woochifer
    Quote:

    Originally Posted by BillB
    Woochifer,

    Are the ceiling panels you used the same panels that would be used in a drop ceiling?

    I think I might be able to talk the wife into those (not a full drop ceiling, just a few tiles) for use on the first reflection point of the ceiling.

    Bill

    Yes, they are the same thing that you would find in an acoustic drop ceiling. I went with those because they were the cheapest option for simple experimenting. Their sound absorption coefficient averages about 0.6, which is okay but not great. Rigid fiberglas panels are more expensive but far more effective. I've been thinking about switching out the ceiling panels for some of those.

    For your purposes (just using them at the reflection points), there are smaller and more attractive options available for ceiling panels. Lowes carries them, and building materials stores should also stock them.
  • 10-18-2004, 11:55 AM
    E-Stat
    Quote:

    Originally Posted by topspeed
    I thought part of the Maggie sound came from their bipolar design? With the diffusers on the back wall combined with the corner traps and room lenses, aren't you severely limiting the bipolar effect? It seems to the layman (that'd be me ;)) that you've turned your Maggies into a monopole.

    The trick is controlling the back wave, not suppressing it. If I really wanted to limit the bipolar effect, I would jam the speakers up against the wall. Here is another pic that better illustrates their "breathing room".

    <img src="http://home.comcast.net/~ralphwallace/images/audio/rear_wall.jpg">

    The idea is to minimize the indirect high frequency reflections as they confuse the image. I find that enhances, not detracts from presenting a spacious image as it renders the spatial cues found on the recording more evident. Separately, the four corner traps are minimizing unavoidable room bass nodes. Although large, the room dimensions are unfortunately close to being even multiples at 30' 6"x 15' x 7' 8" and the nodes abound. BTW, the speakers are Acoustat 2+2 full range electrostats (get my moniker?) although Maggies are similar.


    Quote:

    Originally Posted by topspeed
    Another question regarding the room lenses. How do they affect sound considering their placement within your rig? Are they directing sound radiating towards the side walls, coming off the back wall, both? Just curious...

    Both. Similarly, they are designed to control the reflections. Here is a link to the Argent site that should explain the design:

    <a href="http://www.roomlens.com/RoomLens.html">Argent Room Lens</a href>


    rw
  • 10-18-2004, 12:57 PM
    topspeed
    Thanks for the explaination. I'm still wading thru the math and thankfully TAS does a commendable job of explaining it. Sorry about the confusion on your speaks.
  • 10-18-2004, 01:06 PM
    E-Stat
    Quote:

    Originally Posted by topspeed
    Thanks for the explaination. I'm still wading thru the math and thankfully TAS does a commendable job of explaining it. Sorry about the confusion on your speaks.

    Apology unnecessary. Upon reflection (no pun intended) I find that I failed to link to a website with a detailed explanation of bass traps in my first post as I had intended.

    <a href="http://www.teresaudio.com/haven/traps/traps.html">Bass Traps</a href>

    Be sure to follow the "trap theory and placement" link found at the bottom of the page for some great (if not lengthy) discussion.

    rw
  • 10-18-2004, 02:55 PM
    Bill L
    Only one suggestion...
    for two channel listenig if your TV is between the main speakers. I use a 2'x4' panel of (your favorite acoustic treatment here - I use Sonex) placed in front of the TV for serious listening. It really tightens up the focus in my (small) room. YMMV
  • 10-18-2004, 03:20 PM
    topspeed
    Quote:

    Originally Posted by Bill L
    for two channel listenig if your TV is between the main speakers. I use a 2'x4' panel of (your favorite acoustic treatment here - I use Sonex) placed in front of the TV for serious listening. It really tightens up the focus in my (small) room. YMMV

    My TV is located in an armoire that is recessed into a cove. The two mains therefore are on a plane about two feet in front of the leading edge of the armoire which is flush with the rest of the front wall. Thanks for the advice tho.