Room Treatments for Maggies

[JeremyG]

Hey everybody, long time no post!!!

So I'm coming up on a lot of free time soon, and want to build some room treatments. They can be as big or ungainly as I necessary, since the reason for the free time is a divorce. Yuck.

I have a roll of pink fiberglass on hand. Lowe's is a mile away, so other ingredients are readily accessible. I'm leaning toward 2x4 panels for construction ease, with 1 inch boards attached to a backing board, with the pink insulation stuffed in the middle, all wrapped in burlap. The depth of the boards has not been set, since I need to determine which frequencies to attenuate. The quantity has not been set, either. Burlap apparently is the in thing right now, and between Joann Fabrics and Hobby Lobby there are tons of selections.

Here's my first issue, I own Maggie 1.7s and so far have not found much in the way of any Maggie/dipole specific or unique treatment set ups. Google has so far failed me. I plan on calling Magnepan next week, but thought I'd post here as well to see what the smart people think.

The other rub is that I currently live in an apartment, so I may not be able to get the full effect of treatment panels. But I want to put some up anyway, and like I said can build more to put in storage for an eventual move to a house.

So my question for the masses, does anyone have ideas on treating rooms for medium size dipoles? This will be for music, only.

I plan on taking construction pictures. The only measurement software I have is REW, and the built in Audyssey on my receiver (that does not like the Maggies one bit)

Thanks!!!

[Bill Schneider]

One of the most complete descriptions of listening room requirements for dipoles can be found on Linkwitz' web site where he describes his LX521 dipoles...

http://www.linkwitzlab.com/LX521/Description.htm

[JeremyG]

Well, it happened. It took way too long due to personal issues, but I built some panels.

They're made of Roxul Safe 'n' Sound panels, in 1x3 furring strip frames, wrapped in burlap.


Room measurement before panel installation:

Room measurement after panel installation:


Measurement were with my laptop running REW and using my Rat Shack SPL meter as the mic. Barely scientific, but it still shows the change.

My Maggies sound much better in the vocal range, midrange, and midbass. I'm also glad that I can actually prove it with measurements, and it's not just in my head!!!

[JonMarsh]

Can't see your pictures- would like to, though- did you upload them to HT Guide, or are you using an external server/ISP?

Glad this has worked out for you, would certainly like to see the details. And sorry about the divorce- BTDT.

[JeremyG]

Okay, apparently Dropbox links are no longer working for me. Weird. So I uploaded to the forum. Sorry for the huge pictures.

Thanks Jon!!!

[jim1961]

Your waterfalls are only showing a limited part of the spectrum. The pic only shows a limited portion of the room and don't give us a sense of where the LP and speakers are in relation to it.

[fbov]

+1 to Linkwitz references

+1000 to taking measurements

+Doh! for leaving off the "]" character from your second waterfall. (Image link should close with "[/IMG]")

Finally, try using a LOG scale for frequency; you're only looking at high frequencies.

I see an angled ceiling section in the picture, so I assume a peak somewhere out of the picture. Consider adding these panels to the angled ceiling areas, above the living space. Suspending panels like these a few inches from a surface greatly increases low frequency effect, so try the Log plot and see what the bass region looks like.

Consider plotting as a spectrogram, like this:


General room goals are less than 0.3 sec for 60dB decay, with uniform resonance over the audible frequency range. Your room is still a lttle on the live side, and I can't see the bass respsonse.

Of one thing, I'm certain; you'll kill your room if you take jim1961's advice regarding direct reflections. His thinking is wrong for your speakers.

Have fun,
Frank

[jim1961]

Of one thing, I'm certain; you'll kill your room if you take jim1961's advice regarding direct reflections. His thinking is wrong for your speakers.

Have fun,
Frank

I haven't given any. What advice do you mean?

[fbov]

"Seek out and destroy early room reflections"

The downside of a sig is you forget it's telling us something... My experience says this is never an improvement in a stereo listening room, and I expect it to be even moreso with Maggies.

HAve fun,
Frank

[jim1961]

"Seek out and destroy early room reflections"

The downside of a sig is you forget it's telling us something...

What it should tell you is its just a sig

[gbegland]

"Seek out and destroy early room reflections"

The downside of a sig is you forget it's telling us something... My experience says this is never an improvement in a stereo listening room, and I expect it to be even moreso with Maggies.

HAve fun,
Frank

My experience is exactly the opposite, but I understand where the added(although artificial) ambiance created by dipoles is so appealing to many. For my tastes, killing the early listening room signature without making it too dead has always revealed new layers INTO the recorded sound. When I still ran my Maggies, I never had much of a soundstage to speak of due to a non-symmetrical layout to my room, but placing broadband treatments along the first reflection side walls, gave me a huge improvement.

Greg

[JonMarsh]

My experience is exactly the opposite, but I understand where the added(although artificial) ambiance created by dipoles is so appealing to many. For my tastes, killing the early listening room signature without making it too dead has always revealed new layers INTO the recorded sound. When I still ran my Maggies, I never had much of a soundstage to speak of due to a non-symmetrical layout to my room, but placing broadband treatments along the first reflection side walls, gave me a huge improvement.

Greg

+1 to Greg... makes a big difference. Waiting to see how I can broach that topic with GF- maybe something movable that can be brought into place for critical listening...

[jim1961]

My experience is exactly the opposite, but I understand where the added(although artificial) ambiance created by dipoles is so appealing to many. For my tastes, killing the early listening room signature without making it too dead has always revealed new layers INTO the recorded sound. When I still ran my Maggies, I never had much of a soundstage to speak of due to a non-symmetrical layout to my room, but placing broadband treatments along the first reflection side walls, gave me a huge improvement.

Greg

+1 to Greg... makes a big difference. Waiting to see how I can broach that topic with GF- maybe something movable that can be brought into place for critical listening...

I agree with both of you. But it never fails that when the topic arises, there is someone who claims to prefer almost the exact opposite. I do agree though that dipoles have to be treated differently.

[fbov]

This is one of those areas where personal preferences are strong, and nomenclature misleading. Which is better, in your opinion:

Speaker A reproduces instruments so each one is easily localized in the sound field, a finger's width or so wide, and all sound comes from the front. Speaker location is easily sensed by ear.

Speaker B reproduces instruments so each one fills a portion of the room, wider than your splayed fingers, and the sound wraps around you. Speaker location is masked.

I have both of these... they're actually paired rooms-and-speakers.
- A is the HT, seven speakers, all MTMs
- B is the living room, set up for stereo with two small TM's.

What I've found is that everyone thinks they like A, until they hear B. Where A shines is in professional work, where you only want to hear the sounds you've put in, and nothing else. People like to think they're professionals, and think they ought to design listening spaces like one would a recording or mixing studio. Nothing is further from the truth. All the perceptual data agrees with my ears that B is a far more pleasent listening experience.

That's why I caution folks that "conventional wisdom" isn't always wise. Once informed, they're free to choose... some folks are creating professional spaces, after all!

HAve fun,
Frank

[jim1961]

This is one of those areas where personal preferences are strong, and nomenclature misleading. Which is better, in your opinion:

Speaker A reproduces instruments so each one is easily localized in the sound field, a finger's width or so wide, and all sound comes from the front. Speaker location is easily sensed by ear.

Speaker B reproduces instruments so each one fills a portion of the room, wider than your splayed fingers, and the sound wraps around you. Speaker location is masked.

I have both of these... they're actually paired rooms-and-speakers.
- A is the HT, seven speakers, all MTMs
- B is the living room, set up for stereo with two small TM's.

What I've found is that everyone thinks they like A, until they hear B. Where A shines is in professional work, where you only want to hear the sounds you've put in, and nothing else. People like to think they're professionals, and think they ought to design listening spaces like one would a recording or mixing studio. Nothing is further from the truth. All the perceptual data agrees with my ears that B is a far more pleasent listening experience.

That's why I caution folks that "conventional wisdom" isn't always wise. Once informed, they're free to choose... some folks are creating professional spaces, after all!

HAve fun,
Frank

Speaker A and Speaker B are not the only choices. Pinpoint sound-stage accuracy and certain levels of image broadening and filling are not mutually exclusive. There exist many shades of gray between those two points. In fact, its possible to have the best of both your illustrations in a single space. Perhaps not quite as pinpoint as A, or as spacious and live sounding like B, but strong audible elements of each.

[gbegland]

Speaker A and Speaker B are not the only choices. Pinpoint sound-stage accuracy and certain levels of image broadening and filling are not mutually exclusive. There exist many shades of gray between those two points. In fact, its possible to have the best of both your illustrations in a single space. Perhaps not quite as pinpoint as A, or as spacious and live sounding like B, but strong audible elements of each.

Yes, it just depends on the production of the recording. Most all studio recordings have that pinpoint precise type imaging, but many well-done Blumlein or spaced Omni recordings of classical just present the same, largely diffuse soundfield one would encounter in a hall.

[fbov]

Speaker A and Speaker B are not the only choices...

Agreed, but in my experience at a number of DIY events, designs like Speaker B are few and far between.

[jim1961]

Agreed, but in my experience at a number of DIY events, designs like Speaker B are few and far between.

I think its hard to separate what the speaker is doing from what the room is doing in the sense that one modifies the sound of the other. What individual characteristics each one has separately becomes unimportant by the time you are at the listening position. Now its a synthesis of the two. A sum of two components heard as a single one. Of the two, I would say the room is the bigger contributor. The biggest X factor in how any system sounds.

[JeremyG]

Well, as one who's spent a lot of time very recently in playing with room treatments, I would also like to say that the production of the recording plays a much larger role than I would have expected. I've played with moving all eight panels I've built around my room, on the walls, angles, and laying against furniture. I've also listened to the same recordings whilst in different panel configurations. I can honestly say that, if the recording is crap, fancy speakers with room treatments ain't gonna fix it. Now with recordings that have good production, adding the room treatments to the Maggies helps tremendously to both focus of the soundstage when in the center, as well as to broaden the background, and even when instruments or sounds are panned. Just when I thought Maggies couldn't sound any better. They are also digging much deeper in the lower register than before.

For my personal tastes, putting the panels behind the Maggies killed the broad soundstage, and I had to keep my head in a vise in order to get a good center image. The best positions for myself as well as a friend who was there to help were to put the panels along the side walls and back wall, keeping the front live. I'm thinking about building some diffusers to see if they help when added along the front wall. It appears that I like a slightly more "live" sound than to really deaden it up. Good thing I can do whatever I want in my room!

Music used was Steely Dan's Two Against Nature, a smattering from Porcupine Tree, TesseracT's Altered State, and Redemption's Origin of Ruin.

[JonMarsh]

Found 2" thick Roxul panels in packages of 6 on Amazon from ATS. Put on my list for making some movable floor standing panels with hardwood frames, and having GF pick the panel materials (she likes southwestern themes... this should sell it to her, and allow flexibility for critical listening or "normal" setup out of the way. Thanks for the discussion and sharing results, guys. :T

[Paul W]

Roxul is also available from Lowe's. Saves a hefty shipping charge if you have one nearby.

[JonMarsh]

Thanks- I just checked, and the insulation batts are carried in local Lowe's. OTOH, 2' by 4' x 2" acoustic panels don't appear to be available! (what a surprise! :W ) GF and I are already discussing possibilities, including tri-fold panels like room dividers or the old big Magneplanars!

[jim1961]

Found 2" thick Roxul panels in packages of 6 on Amazon from ATS. Put on my list for making some movable floor standing panels with hardwood frames, and having GF pick the panel materials (she likes southwestern themes... this should sell it to her, and allow flexibility for critical listening or "normal" setup out of the way. Thanks for the discussion and sharing results, guys. :T

I would recommend you double up the material to 4".

[kevinm]

I would recommend you double up the material to 4".

+1. From what I've read, you'll also want the side facing the room to be of the FRK type so that it doesn't over-absorb the high frequencies and over-deaden the room.

[JonMarsh]

I would recommend you double up the material to 4".

:T That was exactly my plan- double panels together. I'm planning to order about a dozen to start off with, for experimentation- throw some test panels together quickly, and in parallel work on a "nice" build concept. Maple or Honey Oak, in all likelihood.

[jim1961]

:T That was exactly my plan- double panels together. I'm planning to order about a dozen to start off with, for experimentation- throw some test panels together quickly, and in parallel work on a "nice" build concept. Maple or Honey Oak, in all likelihood.

Great minds think alike :W

[kevinm]

This thread has a good explanation of some bass absorption recommendations and even has a link to a website with material absorption coefficients.

http://www.avsforum.com/t/691740/membrane-traps-versus-owens-corning-705-frk

[JeremyG]

I ordered my Roxul from Lowe's online. Shipped to the store within a week. Was like $40 for a package of 8 2'x4' panels 3 inches thick, after they discounted it for messing up my original order.

My decorating plan is to find someone with artistic tendencies and get them to paint on them with stain. Maybe an overall theme that would encompass other decorations in the house so the panels would blend in more.

[JonMarsh]

My Roxul panels from ATS arrived yesterday... now this will be added to the backlog of project work!