Seeking Treatment: Merits of Acoustical Panels, Diffusers, Tube Traps, etc.

[DiminishingReturnsOfficer]

It seems that not much is written here on this particular subject. Room treatments are not very closely related to computer audio, but I have a feeling that some of our members use them and have knowledge about their proper implementation. Welcome here are any comments about this subject in its boradest sense as well as specific recommendations for my particular situation. As a quick aside, I find it interesting that the skeptics who regard esoteric interconnects, Power conditioning, and vibration control devices with such derision; generally back off when it comes to acoustic treatments. In fact, many use them or will agree on their merits. A quick glace at some of the products currently available sugggests a great potential for DIY'ing. I would certainly be interested in hearing about anyone's home grown room treatments and how they stack up against the retail contenders.

I'm am currently at the point where I've got my system where I want it to be. I carefully auditioned many speakers, components, and cables, built my own power conditioner, chose an extremely rigid equipment rack, and experimented with vibration isolation devices. It had never been my intent to omit acoustic treatments, but I thought it was best saved for last. Being satisfied that nothing else is going to change, and having my speakers placed optimally, I am now ready to look into it. It seems that the biggest need for treatments are for sidewall reflections and in the corners of the room. I have my speakers set up along the room's long dimension which inherently reduces sidewall reflections. With the nearest sidewall over 8' away, and the speakers toed in, I wasn't planning on doing anything for the sidewalls. It was necessary for me to locate the speakers fairly close to the back wall (18" to the nearest rear corner) and the equipment rack is in between. This configuration does sometimes produce a "one note" bass roar. Overall it offers a reasonably deep soundstage, but the tonal balance is definitely on the warm side of neutral. Its hard to count the times a certain 5 year old ran by missing the speakers only by small fractions of an inch. Bringing them forward even 2" would put them in the danger zone. If similar results can be obtained by acoustic treatments, this would be preferable. I would like to buy some commercially made bass traps. The Real Traps "Bare Traps" sell for $125 for (2) 4'x2'x3 1/2" panels that mount on the wall much the same as you would hang a picture. I'm sure that I could make them cheaper, but I don't know if I could make them better. Since I only need 2, this is my preferred course at the time.

I also sit close to the back wall. Depending on my posture, I could be as close as 10" or less. Its my understanding that its better to use a diffuser in this application. Also, its probably worth mentioning that I often listen from the adjacent room where my computer is. I experimented with an air mattress placed on top of the couch as a deadening panel and didn't like the sound. I have a small display case hanging in the center, but towards the top, of this wall. It's bookcase-like structure allows it to act somewhat like a diffuser. My floor and ceiling are both concrete. With a heavy nap, padded rug; floor reflections aren't much of a problem. I don't know whether it would be advantageous to try something on the ceiling or not. I'm totally open to suggestions.

 

[mitchco]

Aloha! Your room sounds similar like mine.

 

I concur, the speaker to room interface is the least talked about audiophile topic, but one that has the most impact to the quality of sound reproduction. I think it is because acoustic treatments is perceived as either voodoo or boring (probably both and I am kidding ;-)

 

I wrote a few blog posts along these lines at: http://www.computeraudiophile.com/blogs/mitchco Have a quick look to see if there is anything of interest there. My next couple of posts will involve more acoustics, but if you have specific q's, let me know and I will try and answer them.

 

Happy listening!

 

Mitch

 

 

 

[Bones13]

There are a lot of threads about room treatment over at audiokarma. I think that for a speaker based system, you are selling yourself short if you don't even think or try some simple room treatments. (if WAF is there that is)

 

[Norman Varney]

Being my profession, I know that acoustics is usually the last thing people think about when discussing audio, and yet, it is the most important because it has the most impact on the audio experience. Here are a few basic things to consider:

 

There is a hierarchy to playback systems:

1. Physical set up

2. Calibration

3. Acoustics

4. Equipment

 

Achieving optimal room acoustics is a matter of controlling noise and vibrations, room modes, first order reflections and reverberation times in a linear fashion.

 

Regarding your set up, like your speakers, it is beneficial to locate the listener away from the wall to avoid reflections and modes. Without understanding your specific room characteristics, I will just generalize that for a typical (not too live, not too dead) residential room it's a good idea to address the low frequencies (room modes) first, then the first order reflections for each speaker at all six locations, then address the remaining reverberation times.

 

Regarding interior acoustic treatments, there are three tools; absorption, reflection and diffusion. The common room treatments, especially the DIY kind, deal only with absorption, and only address about 500 Hz. (essentially Middle A on a piano) and up. This approach typically leaves the room sounding too dead in the mids and highs, and slow and muddy below. Knowing how much, of what, where, is one of the ways acoustical engineers can turn the audio experience from ho-hum into WOW!

 

[DiminishingReturnsOfficer]

Thanks to Mitch and Bones. I've been reading up on this online. There's a wealth of information in the links you provided as well as at least one Forum dedicated specifically to DIY Acoustic Panels. There's You Tube videos, plans, and instructions. It seems that there is some money to be saved by constructing you own bass trap. Naturally shipping costs on several 48"x24"x4" boxes is going to figure "heavily" (excuse the pun) into the total expenditure. Much like the distinction between HiFi gear and mass market consumer electronics, there appears to be a similar distinction regarding acoustic treatments. RPG, ASC, and Primacoustic offer high quality products at a high quality price. These guys are way out my budget, so I'm going to try to basically assemble my own bass traps. I say "assemble" rather than "make" because I don't plan on doing much other than maybe attaching some fabric to a frame. You can buy ready made frames and sound deadening materials. In fact Ready Acoustics makes something like a slip cover that you just put the material inside and then frame around it (or not). At present, I'm not sure these are available for sale individually or not. They offer them with their DIY kits, and I've got an e-mail in to see about purchasing them individually.

My idea is to assemble 2 standard size (48"x24"x4") bass traps to place behind my speakers. Eventually, I may do something with the ceiling corners and a diffuser for the back wall as well, but I really think these 2 traps will go the farthest in clearing up any thickness in the bass. The first thing I want to determine is the best material for use in the traps. Owings Corning 705 fiberboard seems to be a good choice. They also make a 707 fiberboard which is even more dense at 7lb.s/cubic foot. I've also heard that rock wool is an excellent material. One thing to consider is the overall acoustic response of the material. More dense fiberboards seem to be better at absorbing low frequencies. Does anyone have an opinion or experience with these or other materials?

 

[TechHiFi]

I built my own using a DIY video on You Tube. Contact your local A/C contractor for the OC 703. I have four 4" panels mounted in the corners of the room and two 2" panels behind my speakers (Magnepans) and one 2" panel in front of my TV. I have one more 2" panel that I haven't decided where to place it but I'm leaning towards on the ceiling. For "normal" speakers I would move the ones behind my speakers to the first reflection points on the side walls and the ceiling.

 

[firedog]

Hi -

 

I listen in a small room office. Options for placement are limited, and the sound isn't good. Too much boomy bass, and since I also sit close to the back wall, a reflection off the back wall to my listening area.

 

Originally did DSP Room correction with TACT and KRK-Ergo; this worked quite well (The TACT obviously was better); but for other reasons sold the TACT.

 

So I went for acoustic treatments. I checked the commercial providers involved out and decided to give GIK Acoustics a try.

 

Through their web site I sent in pictures and room measurements, and answered a few questions about what I was after. They responded with 3 different suggestions, with increasing numbers of panels and cost.

 

The basic treatment was just corner bass traps; the better treatment involved panels behind the listening area to prevent reflection back to my ears; the more serious package added panels to prevent reflection at the first reflection points - sides and ceiling.

 

In short, they were very helpful, answered questions, and didn't push me towards the most expensive solution. They clearly were willing to help whether I bought panels or not, and would have been perfectly happy if I had gone for the least expensive solution offered.

 

Some of the other companies in the field offer a similar service - I recommend you contact one of them and take advantage of their knowledge - it will help, even if you do DIY. And BTW, GIK and some of the other companies will sell you their specialized acoustic materials, so you can make fully effective panels yourself, if that's what you want to do. I'd also look which companies will sell you materials at a decent price. It's not only the filler which is important. Good panels also use special fabrics which increase their effectiveness. Other kinds of fabric may be ineffective or even damage your results.

 

Based on my experience, I'd say the biggest benefit would be obtained by getting corner bass traps. This alone will probably greatly benefit the sound. Getting the big bass reflections cleaned up not only improves the bass, but lets you hear the mids and highs more clearly. After that, you'd probably want to tackle reflections off the back wall behind your head (I'd think if your are that close to the wall you are definitely hearing reflections from behind), and then 1st reflection points. There are some simple tests you can run to see where your first reflection points are (or aren't, as you may not have them on all walls, depending on your setup).

 

If you've never been in a room with proper acoustic treatment (panels or DSP) I think you are in for a treat. Even in a good room you will find noticeable improvements and increased clarity. In a bad room you may even find the improvements astonishing.

 

If you are an audiophile, I'd say that some kind of acoustic treatment is a must. For a modest sum in audiophile terms (as little as $200-$300 for a few pre-made panels or for materials) you can improve the sound of your setup more than you could with many expensive equipment upgrades.

 

I'm also surprised by the number of audiophiles with 5 and even 6 figure systems who ignore "the room" as perhaps their most important component. Room treatment is one of the most cost effective ways you can improve the SQ of your setup.

 

[wgb113]

What are the dimensions of your space? I too have my primary 2-ch system in what was a small home office.

 

Bill

 

[firedog]

Internal (wall to wall):

455cm L X 298 W X245cm H

14.93 ft X 9.8ft W X 8.03ft H

 

 

 

or 33.3 (cu meters) = 1,173 cu feet

 

or approx 13.6 sq m = 146 sq feet

 

I sit about 8 feet from the speakers. The speakers are about 2.5 ft from the far wall and 2 ft from the side walls. My position is about 3ft from the back wall

 

 

[bdiament]

Hi DRO,

 

"...Being satisfied that nothing else is going to change, and having my speakers placed optimally, I am now ready to look into it...."

 

I would not be surprised if proper room treatment results in a change in speaker and/or listening position(s).

 

"...It seems that the biggest need for treatments are for sidewall reflections and in the corners of the room. I have my speakers set up along the room's long dimension which inherently reduces sidewall reflections. With the nearest sidewall over 8' away, and the speakers toed in, I wasn't planning on doing anything for the sidewalls. It was necessary for me to locate the speakers fairly close to the back wall (18" to the nearest rear corner) and the equipment rack is in between. This configuration does sometimes produce a "one note" bass roar. Overall it offers a reasonably deep soundstage, but the tonal balance is definitely on the warm side of neutral..."

 

I would say the biggest need for treatments is to control room modes and early reflections. The corners are just one location in which to address modes but corners alone will not fully address the issue. Early reflections will occur on all room surfaces, not simply the side walls.

 

Using a long wall setup does not reduce side wall reflections, it merely delays them in time. (Granted the energy is measurably diminished with the added travel time to the first reflection point but with the difference in a typical room, even a large residential room, the energy is, as far as the listening is concerned, effectively the same. The greater distance only means the position of early reflection treatment on the side walls will change, not the need for the treatments.

 

With placement close to the wall behind the speakers, there are certain realities that will not change, even with optimal room treatment. For example, soundstage depth will be foreshortened. Close proximity to a boundary like a wall means the room's modes will be stimulated more than they would be by more optimal placement. (This is part of the "one note" bass you refer to.) However, I understand that in some situations, this is the best a listener can do and this is what the listener has to work with.

 

 

"...I also sit close to the back wall. Depending on my posture, I could be as close as 10" or less. Its my understanding that its better to use a diffuser in this application. Also, its probably worth mentioning that I often listen from the adjacent room where my computer is. I experimented with an air mattress placed on top of the couch as a deadening panel and didn't like the sound. I have a small display case hanging in the center, but towards the top, of this wall. It's bookcase-like structure allows it to act somewhat like a diffuser. My floor and ceiling are both concrete. With a heavy nap, padded rug; floor reflections aren't much of a problem. I don't know whether it would be advantageous to try something on the ceiling or not. I'm totally open to suggestions..."

 

Sitting close to the wall behind the listening position puts you in a pressure zone, exacerbating the "one note" bass.

 

I would very much disagree with placing a diffusor behind the listening position. What is required there is absorption of the reflections from the wall behind you (there will be one reflection point for each loudspeaker on every room surface). Applying diffusion only serves to guarantee those reflections will find your ears.

 

It is the same when you see photos of diffusion placed at other early reflection points, particularly near the loudspeakers. Early reflections tend to blur the image, obscure low level detail and harden tonality. Diffusing (i.e. scattering) them only ensures they will arrive at the listener's ears, regardless of where the listener is.

 

In my experience, the problems of early reflections are removed when those are absorbed. (In my opinion, this is about the only useful thing flat panels can do. And it can be accomplished other ways too, as I'll mention below.)

 

Diffusion should be used only for late reflections, to help keep a sense of "life" in the listening space, yet not interfere with the direct sound from the loudspeakers.

 

I'm not surprised the air mattress didn't work and not at all surprised that it would make things worse. These will never work as a "deadening panel" since they are quite resonant on their own and tend to have reflective surfaces.

 

After trying all sorts of "acoustic treatments" over the years and finding most to be no better than hanging a bathroom towel in their place (and some to be downright detrimental to acoustics!), I found the modern iteration of Harry Olsen's "cylindrical sound absorbers". They are available commercially in the form of ASC's wonderful Tube Traps but there are a few good DIY (do it yourself) recipes on the Web.

 

A well designed cylindrical "trap" provides not only treatment for room modes but also early reflection absorption and late reflection diffusion - all in a single device. For a good starting point for a DIY recipe, do a search on "Jon Gale". I started with that recipe and made a few modifications (among other things, I used plywood for the end circles instead of drywall).

 

A good article on placing and using devices like these can be found here: http://www.asc-hifi.com/articles/iar89.htm

(I would take some of the statements, particularly those referring to a "laboratory" with a good degree of salt but outside of that, I think the article is good enough to recommend.)

 

For a few photos of traps I built for a client, see:

http://www.swordinthestonerecords.com/totw/photos.html

(Click on thumbnails for larger views.)

 

And perhaps an article I wrote several years ago will be of interest:

http://www.barrydiamentaudio.com/monitoring.htm

 

Hope this helps.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[Jsmith]

I also listen in a small office. It is about 12x12. I sit very close to the wall opposite to my speakers, and have my speakers very close to the back wall.

 

As you can tell I am a student of Jim Smith or trying to be. I have placed a ficus plant behind my speakers in the corners. The front wall corners are not 90 degrees but actually 30-45.

 

I have also placed four (2'x2') ATS panels beyond my listening position to create a 4' square absorption for the back panel reflection.

 

I have been very happy with this so far and feel it made a noticeable difference without going overboard. I am considering some panels at the first side reflection point and curtains for a window, but need the money first.

 

FYI - I used the ATS Coffee Bag panels to try and not look so much like a studio. They were a bit of a pain to use as the coffee bag had seems and other bulk that I had to account for.

 

 

 

[mitchco]

Try and get your hands on a copy of Alton's book on Acoustic Techniques for Home and Studio:

 

http://www.amazon.com/Acoustic-techniques-studio-Alton-Everest/dp/0830606963/ref=sr_1_2?s=books&ie=UTF8&qid=1319137069&sr=1-2

 

Looks like you can get a copy for under $30.

 

The book goes into great detail on calculating room modes based on the dimensions of your room. From there Alton shows you how to plot those room modes and then home build a Helmholtz absorber that is tuned to those room mode frequencies with the right amount of absorption.

 

My point is that you can calculate your room's resonances and design & build a filter to tame those specific frequencies. It has been my experience that without calculations and/or measurements, everything is a best guess.

 

If you have access to a calibrated mic and sound card, you could measure the resonances and verify the calculations. Then after the build and placement, you can verify it works by re-measuring.

 

Here is a room mode calculator that you can quickly calculate your rooms resonances: http://www.mcsquared.com/modecalc.htm

 

Finally, you could also incorporate DRC like: http://www.computeraudiophile.com/blogs/Hear-music-way-it-was-intended-be-reproduced-part-4

 

Hope that helps.

 

 

[4est]

Do not forget to look into fiberglass at a local acoustical supply house. Most cities will have suppliers in their metro areas. Here, 4" 2'x4' fiberglass panels are under $20 a pop. They are easy to cover with fabric and spray contact adhesive and easy to mount.

 

[DiminishingReturnsOfficer]

Thanks for all your input. Barry, yours was particularly helpful. Someone else may have mentioned it as well, but I'm glad you straightened me out on diffuser on the back wall being a bad idea. You're right, I definitely want to try to absorb what's coming off that wall especially with as close to it as my head is. I've been reading the Acoustics section in Robert Harley's "Guide to High End Audio", and consulting with Bryan at GIK.

At present, what I (we) have in mind is first treating that back wall with (2) 48"x24"x4" bass traps (GIK 244's). The front wall, behind the speakers, will get the same, but I may have to wait on that purchase. I'm also thinking to eventually go with a GIK 242 which treats higher frequency reflections on the nearest sidewall, and perhaps a free standing bass trap in front of my door that could be moved easily.

I think Barry was also probably right about using an air mattress as an acoustic panel. It did change the sound, but definitely not for the better. The membrane was probably acting like a big drum! In other words, this was not a fair test and therefore lead to a wrong conclusion about needing a diffuser.

 

 

[bdiament]

I'd like to offer my own perspective on this.

 

The trouble I've found with most simple measurements is they implicitly assume the listener has a very narrow head with a single ear in the center of their face.

 

Most that narrow headed listener half and inch and the measurements can change drastically.

 

The fundamental frequencies of all room modes can be calculated quite simply but ultimately, in my experience, the treatment requirements remain precisely the same unless the room is unusually large or unusually small.

 

In other words, what will change is the maximum diameter trapping needed to successfully address the room's lowest fundamental resonance mode. In the overwhelming majority of domestic -and even many commercial- spaces, the requirements will not change substantially. (There will be other considerations for the exceptions, where the room is either tiny or gigantic.)

 

Generally speaking, the places where boundaries meet (e.g. corners) will need to address the fundamental modes, the mid-points will need to address the first harmonic of those modes and the quarter points will need to address the second harmonic of those modes. Since the second harmonic will be in the mid or upper bass, the traps in these places can be smaller in diameter than those in the corners and mid-points.

 

In the treble, there will be an early reflection for each speaker on each room boundary (or surface in the path). Absorption at these points will address the problem. Absorption beyond these points (as seen in many studio photographs) results in a "dead" room. (A padded cell does not have the best sound. ;-} )

 

Providing diffusion for late reflections will maintain the "life" in the room without interfering with the sound from the speakers.

 

Knowing the precise frequencies where the modes occur will not change any of this (again, except in tiny or gigantic rooms). Room size, speaker placement and listening position will determine where the early reflection absorption and late reflection diffusion needs to be placed.

 

Room treatment isn't really very complicated.

Addressing resonant modes in the bass with trapping, early reflections with absorption and late reflections with diffusion is all that is required.

 

I've already spoken about locations for resonant mode trapping.

Reflection locations can be found easily too. With the listener at the listening position, an assistant holds a mirror against each wall (at the listener's eye level). As the assistant moves the mirror, when the person at the listening position sees a reflection of one of the loudspeakers, they've found the point that needs absorption.

 

I've worked in many studios over the years and seen all sorts of designs. I've seen folks come in with thousands of dollars with of test equipment. And I've heard the dismal results in all too many cases. What I've outlined above is something I've used in many rooms, including my own. It works every time and no test tones are required. ;-}

 

The difference such treatment makes can be easily heard even before the system is turned on. Conversation in such a space becomes much easier to understand. This is because the room is no longer "ringing" (the frequency of the ring becomes irrelevant; what is needed is the absence of the ring).

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[bdiament]

Hi DRO,

 

I would very much recommend checking out the Jon Gale link I suggested earlier.

 

It is possible to address room modes (in the bass) and early as well as late reflections (in the treble) using a single type of device.

 

I am not a fan of panels myself. They can absorb treble reflections (so can a $5 bath towel) and for my ears, just don't have the volume to address bass problems. (I know many panel makers publish graphs. This is fine if one listens to graphs. ;-})

 

DIY traps such as the Gale design can be made for ~$20 per trap (vs. >$500 for the admittedly excellent commercial variety from ASC). I built enough to treat my whole studio/listening room for just over $500.

 

 

Whichever way you go, have fun!

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[Jsmith]

Here is a question on this topic someone maybe able to answer. On one of the side walls of my speakers I have french doors into my office. The first reflection point in on the doors.

 

So....... would it presumably be better to close the doors and put a panel there to absorb, or could I achieve a similar result by opening the doors which in my mind would allow the sound out of the room and not reflect?

 

 

 

[Priaptor]

In my last home I actually built a separate sound room.

 

In my current home I have had to make a very large room work. I am "almost" there and I too find ASC tube traps to be wonderful products. I have basically used many traps to create a smaller listening environment within a larger one

 

A question and a comment.

 

The primary side reflection point, would you recommend, having the tube traps reflection/diffusing side facing towards or away from the listener? I have tried both.

 

The comment I want to make is that, while I usually prefer stand mounted speakers, I am currently listening to large linear array speaker in the form of NOLA Baby Grands. One of the biggest differences I have been able to affect on my listening experience is the height of my listening position. I was kind of amazed at how placing a Tempurdic seat cushion under my rear end raising my ears about 2-3 inches made such a huge difference. I think one's chair and listening height are rarely addressed and can make some of the biggest differences.

 

[Jsmith]

I could not agree more to the height of the listening seat affecting the sound. Jim Smith covers this in his Get Better Sound. (I swear I am not affiliated just a very pleased customer).

 

Since my listening room is a home office my chair normally sits a bit too high as I think most speaker manufactures assume 36" listening height. Right now my speakers are on a pretty steep angle, where my front spikes are almost fully out, and the rears almost fully recessed. Even with this, at night when I am in serious listening mode, I drop my office chair to it's lowest setting.

 

[bdiament]

Hi Jsmith,

 

Just as applying absorption to the door will, opening the door would eliminate the reflection from the door.

 

However, opening the door would mean the reflection would occur later, after the sound entered and bounced around in the adjacent space.

 

So the results of opening the doors would be more different from applying absorption to the closed doors, than they would be the same. The reflection from the office would be delayed and this would be beneficial (in comparison with closed, untreated doors).

 

If the reflection from the office bounced around the office a bit as opposed to being returned from a flat surface (say, a desk), I'd say opening the doors would do the job. Of course, this assumes the reflection path to the listener was centered on the doors when they are closed. It also assumes a single listener at a single listening position. Add another listener and/or move a bit and the wall on either side of the door becomes the reflection point for that position.

 

Hope this helps.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[bdiament]

Hi Priaptor,

 

What did you hear when changing the orientation of your traps?

 

I generally start trap setup by facing the "dead" side of each trap along the front and sides of the room toward the tweeter of the nearest speaker.

 

Traps toward the rear of the room have their "dead" side facing the listening position.

 

Traps in the center of the front or rear wall have their "dead" side facing the center of the room.

 

This setup ensures direct early reflections are absorbed and later reflections are diffused.

 

Listening position height (or loudspeaker height) is definitely something to consider with quasi-omni monopoles (i.e. box speakers). This is true to a degree (as you've found) even with speakers that utilize dipolar tweeter and midrange units when those are not in a line array of sufficient length to make height a non-issue.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com

 

 

[mitchco]

re: open the door? Without actually seeing your room... If it were me, I would close the door and put a panel there.

 

Sound waves are just like water waves - throw the pebble in water and watch the waves. Put something in the way (or open in your case) and the wave distorts.

 

re: measurement asumptions:

 

 

I built the panels, diffusers, and tubes from scratch that you see in this listening room. The TEF computer measures sound in 3D and revolutionized the audio measurement field: http://www.tvtechnology.com/article/93738

 

Btw, what you are seeing on the TEF screen is amplitude (vertical scale) versus frequency (horizontal scale) over time (Z-scale). Note that the room's resonance and RT60 decay times are the same across a wide band of low end frequencies = a very nicely tuned room. Even if you move the microphone around, you get a very simlar picture.

 

Flash forward today and look at the state of the art in acoustic measurement software and digital room correction (DRC) software. It depends on your budget and how "perfect" you want to go. For under $400 you can achieve a level of room acoustic correction that no amount of panels, diffusers, or bass traps can achieve: http://www.computeraudiophile.com/blogs/Hear-music-way-it-was-intended-be-reproduced-part-4 Wish you could hear it...

 

The bottom line is that any properly placed acoustical treatment is likely to help as Barry points out. However, it is to what degree you want to go with your given budget and whether DRC and/or room treatment will provide the best bang for your musical dollar.

 

 

[Priaptor]

Right now, I have one trap on each side and I too find having the dead side facing the speaker yields best results. I had my dealer bring over 4 additional traps having three per side and having all the dead sides facing speaker and listener deadened the environment too much. The best result with three per side (in my room)was the one closest to the speaker dead side facing speaker, the one closest to listener dead side facing the listener and the middle one slight recessed from the other two and reflecting/diffusing side facing middle of the room slightly angled each side, if one drew a line from the center of the trap meeting about two feet in from of the listening "sweet spot".

 

Right now I have only one per side and those in the side and in the middle (between speaker in front of room) are set as you recommend and my traps in the corners as per manufacturer recommendation of diffusing side facing towards middle of room.

 

 

 

[Marcus1320]

I haven't had much time to read all these great posts but I thought I'd add that Auralex Acoustics has some great products and information on room acoustics. I've used the products in our edit suites and it worked great without breaking the budget. http://auralex.com/

 

[bdiament]

I know folks who love their DRC.

 

For my ears (I've heard a great many approaches from different manufacturers and even wrote the manual for one) the technology needs time before it works - if it ever will work.

 

I say this because the changes wrought by DRC are quite easy to hear and often very dramatic. But, in my opinion, change is not the same as improvement.

 

Getting down to basics, room issues are time-based phenomena. Essentially, it is the room "holding onto" a sound after it has stopped in the source material and the speaker is no longer presenting the sound to the room.

 

DRC and other EQ type solutions are amplitude-based. They adjust the level of different frequencies but cannot adjust the time. Yes, some have a time function but that is addressing attack (such as compensating for minor differences in speaker to listener distance), not the decay, where the real problems exist.

 

There is another issue with these "solutions" that is not generally spoken of. That is that in changing the direct output of the speakers in the effort to "compensate" for issues that do not originate in the speakers results in a skewed direct response. This is the first sound the listener hears, before the room enters into the equation and it is the sound that largely determines the overall character of reproduction.

 

So in addition to not solving the problem, I find such approaches create an additional problem, in essence, messing up the direct sound from fine loudspeakers. What started as just a set of room issues is now a set of room issues with diminished performance from the speakers.

 

Clearly, as with anything else in audio, there is a diversity of opinions on this. Mine is that seeking to fix time-based problems with amplitude-based "solutions" is like trying to fix a broken arm by wearing a different hat.

 

My personal experience, across many years, many systems and many rooms, both domestic listening spaces and professional studios has been consistent: the best sounding rooms address the room issues at the source, i.e. the room. Those using other approaches to "correction" invariable place more system "character", rather than less, between the listener and the recording, hampering the "getting out of the way" magic that well set up systems can demonstrate.

 

Just my perspective, of course.

 

Best regards,

Barry

www.soundkeeperrecordings.com

www.barrydiamentaudio.com