[Bob in St. Louis]

Hello fellas,
First I have some blabbering, then a few direct questions:

Blabbering:
So I find myself with an overwhelming desire to treat my Home Theater/Two Channel room. Conveniently, I'm also in possesion of small sum of cash. Enough for three boxes of "703". I was "this" close to placing the order this morning and had a thought: "What am I doing"?  More specifically, "What exactly is my goal"?
So I realise it's not brain surgery to wrap some 703 with a visually acceptable material and hang it on walls in the proper locations (it takes about 5 minutes of research online to learn the definition of 'proper location' after all). But....What am I trying to accomplish? Of course I'm treating my room, but treating it for what? Do I have a problem from 60Hz to 90Hz? Or is it from 2,487.4Hz to 2,754.1Hz? Or room modes, decay, nulls, or....
I know that ALL rooms need a certain amount of treatment, just the nature of the beast. But if I get a few boxes of 703 and sprinkle the panels around my room, do I THEN take measurements or do I leave my room in it's current (untreated) state and measure first to pinpoint exact problem areas. What if I buy a bunch of 703, line my walls only to find out I should have bought 705 instead? (that would make Bob a very unhappy boy). What if, a problem area I have is made worse by me blindly Spackling my walls with fiberglass? THEN I do measurements only to find out I need to throw away half of what I bought.
I see thread after thread, article after article talking about the virtues of treatments, but nowhere does anybody talk about how they came to the conclusion to do what they did. They just hang stuff on their walls and talk about how great it is. Couldn't possibly be that easy.....could it?

Direct Questions:
#1 What are the proper steps in sequence to properly treating a room.

#2 When measuring a rooms response and looking at your graph, how do you know that the results are a "picture" of your room, or a "picture" of what your speakers are creating. (One repaired with treatments, the other with EQ / crossovers etc..). Or am I supposed to drag my speakers into the middle of a football field and measure them to see what they're doing separate from the room?

#3 Or, will I get "95%" of the way there by using a couple boxes of 703 and build some bass traps, and we'll call the rest "the proverbial point of diminishing returns".

#3 I'll have more questions, but am not intelligent enough in the subject to know what they are yet.

Thanks guys,
Bob

[woodsyi]

Forget measurements and tests.  You got walls -- you got issues.  Most rectangular rooms with 2000 to 4000 cubic feet will benefit from bass traps in tri-corners, absorption behind speakers, diffusion behind listening position and absorption/diffusion on first reflection points.  Then you can blabber about how good your room sounds. 

[nathanm]

My impression is that (for most small or medium-sized rooms) it boils down to running out of space or money before achieving the required amount of absorption to get to the desired amount of frequency flatness.  But luckily you will appreciate the journey because whatever you do put up will indeed absorb those reflections and give you a more focused, quiet and intimate sound.  I'm not technically inclined and actual smart people will be able to give you better answers, but I know that I just started lining my walls with absorption with nary a measurement mic to be seen, and loved every minute of it.  Is there still a colossus of a 40Hz peak in there?  Sure is, but I would need to entomb myself in fiberglass to knock it down.  (A little EQ to the rescue) To me you have to enter a realm of super hardcorene$$ to really get to Flat City.  (scratch-built rooms, computer analysis, costly and numerous treatments etc.)  But the podunk solution of "Hey I'll build some traps and stick 'em up" works too.  It's all relative.

[Bob in St. Louis]

Most rectangular rooms ......will benefit from ......absorption behind speakers

The entire front wall is my "rebound area" for open baffle............in case that matters. 
Not much info regarding open baffle and treating a room. I would assume there's a difference???/

Nathan, I like the podunk method. I'm good at that. 

I've posted enough pictures of my room on (too many) threads so I'll spare you guys unless you think it will help, but as Nathan said, I'll most likely run out of space before I "have enough". My walls are pretty full without having panels on them.

Thanks guys,
Bob

[bpape]

The trick is to address specific issues yet still have a balanced scheme.  Having a room serve dual purposes for HT and 2 channel poses some issues as some of the design goals are different.  You just have to decide which way you want to lean.  The first thing I'd do is make sure you have your seating in the best place possible within the restrictions prior to doing any treatment.  That gives you the best 'canvas' to start with.

Broadband bass control is, IMO, the fist thing to be addressed.  After that, it's early destructive reflections.  Then we take a look and see what's left to address.  That won't take a lot of space.

Bryan

[Bob in St. Louis]

- Yes, it is a dual purpose room Bryan. If I where to say I'd like to lean to the two channel side of things, would it be safe in assuming it wouldn't do anything drastically objectionable to the HT side of things?
I call myself a HT guy, but YOU people have poisoned me with all this good music. 

- Ok, tell me if I've got this correct:
-- First reflection points would be taken care of by installing 703 panels. Correct?
-- Broadband bass control would be taken care of by using 703 panels cut into the typical triangular shapes that would fill the corners between wall to wall, ceiling to wall, and wall to floor. Correct?

Bob

[youngho]

I am going to take a contrarian tack and argue for at least some measurements. It's good that you are considering your goals carefully, since your personal preferences may differ from those of others on this forum, and your system is a little complicated. A few examples:

1. Open baffle configurations usually result in a dipolar radiation pattern, meaning that the orientation of the speakers may result in a null in terms of the soundfield where a first reflection from a sidewall would normally be. Putting absorption at this point would not be cost-effective, obviously.

2. Dipoles often benefit from diffusion, rather than absorption, of the rear wave, at least according to many Magnepan owners, as well as Siegfried Linkwitz and others.

3. You seem to have an infinite baffle subwoofer system. Depending on how the subwoofers are located configured and where the crossover frequency is, some room modes may not be activated, and if not, they would not need to be treated. For example, if your infinite baffle subwoofer drivers are all located in the middle of your ceiling, you don't need to worry about the odd-order length and width modes if these frequencies are reproduced by the subwoofer.

I have only an amateur's interest, but I would argue that a reasonable sequence for approaching basic room acoustics would be:

1. Furnish the room with the elements that you plan to have in there.
2. Place the speakers and the listening position in reasonable locations. Adjust until you're happy.
3. Make some measurements at the listening position, particularly below the transition frequencies where room resonances really become evident
4. Adjust positions of speakers and furnishings to compensate for some of these issues, continue until you're happy.
5. Identify issues and goals for room treatment, as well as a budget, and figure out where your money is best spent.

All rooms will benefit from bass trapping, but most rooms will have some already built in in terms of drywall mounting on studs. Lateral modes might be alleviated by symmetrical placement of woofer elements 25% from the sidewalls. Longitudinal modes might be alleviated by pulling the speakers forward from the rear wall and positioning the listener somewhere between 50% and 75% of the distance from the front wall. Vertical modes might not be a significant issue for a seated listener in a room that is 8' tall or more. Why spend money addressing a problem that is not apparent at the listening position?

Young-Ho

[Ethan Winer]

will I get "95%" of the way there by using a couple boxes of 703 and build some bass traps, and we'll call the rest "the proverbial point of diminishing returns".

Yes. Bass traps in as many corners as you can manage, plus absorption at the first reflection points, and you're 90 percent done. Maybe even 100 percent. If you look at the various photos on my site you'll see a common denominator. Imitate that and you're on the right track.

As for measuring, it's not strictly needed but it can be useful. I usually tell people to measure just so they can see how horrible their room really is. Most people don't even know they need treatment! Though that is changing. The other reason to measure is to see how things improve as you add bass traps and other treatment. So it's more peace of mind and satisfaction, versus measuring to know where to treat. You already know where to treat.

--Ethan

[bpape]

I'd agree with youngho to a point - that we don't want to do any more than is necessary - especially when leaning toward 2 channel usage. 

Measurements can be helpful in determining where specific bass issues are and where they might be coming from.  While the OB speakers do certainly offer a different perspective as to how to treat the wall behind, in this particular case, diffusion may or may not be required - but absorption probably is not. 

In short, yes, 2-3 boxes of 703 will give you the 90% solution by addressing broadband bass control, general decay times, and early reflections.  After that, it's tweaking to the specifics of what the room needs.

Bryan

[Bob in St. Louis]

Young-Ho - Interesting... There's some good points in there. The cost of a couple panels in the null area of an Open Baffle zone doesn't bother me too much. These panels are fairly inexpensive when purchased by the case and one on each side shouldn't break the bank. My biggest fear is screwing something up after treating the entire room and then having to diagnose which panel(s) doesn't belong.
Regarding the front wall, the screen is cloth covered wood (torsion panel construction) and of course reflective. Not much I can do about that at this point without major renovation. You see, the screen (5.5' tall X 10' wide) is hinged and there's storage shelves in there. In addition, this is where the Infinite Baffle (IB) drivers live. The point is that I can't make the screen out of something that will allow the IB rear wave to come into the room. So diffusion is (almost) out of the question. The one pretty neat thing I can do; My screen is surrounded by cabinetry. In critical listening situations I can open all the cabinet doors which naturally provides a certain amount of diffusion when all of the doors are opened 90 degrees. I've had daydreams of filling the cabinets with treatments, either DIY diffusion "inserts" or absorption "inserts". This way I could open just the right amount of doors as needed.
What do you think of that?  aa

Ethan - Ok, I think you've clenched it as far as I'm concerned. Your "imitating the common denominator" suggestion confirmed my suspicions. Obviously there's a reason well treated rooms are well treated, if you know what I mean.
It would be fun and a good learning experience to measure before, during and after treating just to see what happens along the way (I read your article about EQing versus MondoTraps with great interest) however, my goal here is to get 90+% of the way there and sweat the details some other day. Too many things need to be done at the house and being overly 'anal' about any one of them would not serve me well (W.A.F.  ).


Ok, back to specifics;
-- I'll be using 703 for panels AND to build bass and corner traps. Right?

-- Regarding the ceiling, I don't have any good photos of the ceiling but the center 1/3 (widthwise) of it is drywall and consists of six 30"X30"X18" (approx) "cubbies", each with a single recessed lighting fixture. Should I treat up there?
This is the best photo I've got of the ceiling. There's a few more in my signature, but none of them are any more revealing.

Thanks again fellas!
Bob

EDIT: Hey Bryan, Understood about not wanting more absorption on the front wall (behind the OB speakers). If more diffusion is needed I can do what I mentioned above and fill the cabinets with neat little diffusion contraptions. Shouldn't be a problem.
Check your PM.  Looks like it's time for me to ----->

[hmen]

Forget measurements and tests.  You got walls -- you got issues.  Most rectangular rooms with 2000 to 4000 cubic feet will benefit from bass traps in tri-corners, absorption behind speakers, diffusion behind listening position and absorption/diffusion on first reflection points.  Then you can blabber about how good your room sounds. 

I could not have said it better my self. Do the corners, especially those behind the speakers, the wall behind the speakers, first reflection points and then just sit back and enjoy. When i first purchased my realtraps I just looked through the gallery, saw where other people hung their sound treatments and did the same. The improvement was so dramatic that I just declared victory after listening for about 10 minutes and never measured anything.

[Bob in St. Louis]

The improvement was so dramatic that I just declared victory after listening for about 10 minutes and never measured anything.

That's what I'm hoping for.  aa

Given the lack of information regarding OB and room treatments, it looks like this will require some experimentation on my part.
The front wall of the room seems to be the gray area regarding treatment type.

Bob

[Ethan Winer]

When i first purchased my realtraps I just looked through the gallery, saw where other people hung their sound treatments and did the same. The improvement was so dramatic that I just declared victory after listening for about 10 minutes and never measured anything.

Exactly.

[satfrat]

Forget measurements and tests.  You got walls -- you got issues.  Most rectangular rooms with 2000 to 4000 cubic feet will benefit from bass traps in tri-corners, absorption behind speakers, diffusion behind listening position and absorption/diffusion on first reflection points.  Then you can blabber about how good your room sounds. 

I could not have said it better my self. Do the corners, especially those behind the speakers, the wall behind the speakers, first reflection points and then just sit back and enjoy. When i first purchased my realtraps I just looked through the gallery, saw where other people hung their sound treatments and did the same. The improvement was so dramatic that I just declared victory after listening for about 10 minutes and never measured anything.

A while back i suggested that as an option to room testing an audiophile could always trust his ears. I got chastised to the point of apologising for even suggesting this. So I congratulate you hmen for receiving your "Exactly".

Cheers,
Robin

[Ethan Winer]

There's nothing wrong with listening and using your ears! But it's not as repeatable as measuring. More important, the key of the music you play interacts with the room's resonances, so you'd have to be methodical and select music in different keys. The appeal of measuring is you can test all frequencies in a single five-second sweep.

Or forget all that and just stick up a bunch of panels in the usual places.

--Ethan

[Bob in St. Louis]

Or forget all that and just stick up a bunch of panels in the usual places.

Yip. Doing this very thing make one heckuva difference.

I'd like to personally thank all of you who posted (Especially Bryan who personally delivered the product). 

I have had only a short time with the panels randomly scattered "in the usual places" and the words that comes to mind are Geez man, why didn't I do this sooner"? 

We've all read the thread when a guy treats his room, then rants and raves about how much better it sounds. We also all know (from reading forums) how important room treatments are. But why do most of us wait so long to do it? Personally for me, in all honesty, it's because there's no cool factor. There's is no brushed aluminum, no pretty flashing LED's, no new cool toy to add to the equipment rack. Nothing.... Hell, it's about as cool as hanging pictures on a wall but in this case, the picture is blank. How much more boring could panels on a wall be? 
I suppose the only advantage of waiting to treat your room until last, is that it makes you appreciate it so much more. The night and day difference it makes is nothing short of stunning. Even with all of the equipment turned off I can tell the room is quieter. Like it lowers the noise floor. Is this what I'm hearing? (Or NOT hearing is more accurate).

Anybody sitting on the fence regarding room treatments should get off the damn fence and get it done. Once you hear the difference, you'll be kicking yourself for waiting so long. Trust me.
The difference was big enough ...... no ...... impressive enough, that I almost called in sick to work today so I could stay at home and play with my new toy. This is the second time in my "audio life" I've had this level of excitement for a product, or a change I've made.
Yea, it's that big of a deal. 

Again guys, thank you very much for the assistance in this thread and in every other acoustic thread or article I've read over the years.
Sorry it took me so long to 'see the light'. 

Bob

[bpape]

Good deal Bob.  Yes - it can make quite a difference.  You're right, the OB's do present a little more of a challenge in your setup but there are many ways to skin the cat.

Bryan

[satfrat]

Or forget all that and just stick up a bunch of panels in the usual places.

Yip. Doing this very thing make one heckuva difference.

I'd like to personally thank all of you who posted (Especially Bryan who personally delivered the product). 

I have had only a short time with the panels randomly scattered "in the usual places" and the words that comes to mind are Geez man, why didn't I do this sooner"? 

We've all read the thread when a guy treats his room, then rants and raves about how much better it sounds. We also all know (from reading forums) how important room treatments are. But why do most of us wait so long to do it? Personally for me, in all honesty, it's because there's no cool factor. There's is no brushed aluminum, no pretty flashing LED's, no new cool toy to add to the equipment rack. Nothing.... Hell, it's about as cool as hanging pictures on a wall but in this case, the picture is blank. How much more boring could panels on a wall be? 
I suppose the only advantage of waiting to treat your room until last, is that it makes you appreciate it so much more. The night and day difference it makes is nothing short of stunning. Even with all of the equipment turned off I can tell the room is quieter. Like it lowers the noise floor. Is this what I'm hearing? (Or NOT hearing is more accurate).

Anybody sitting on the fence regarding room treatments should get off the damn fence and get it done. Once you hear the difference, you'll be kicking yourself for waiting so long. Trust me.
The difference was big enough ...... no ...... impressive enough, that I almost called in sick to work today so I could stay at home and play with my new toy. This is the second time in my "audio life" I've had this level of excitement for a product, or a change I've made.
Yea, it's that big of a deal. 

Again guys, thank you very much for the assistance in this thread and in every other acoustic thread or article I've read over the years.
Sorry it took me so long to 'see the light'. 

 Bob

How many beers have you been drinking Bob???


Just kidding with ya Bob. I've have pretty much the same reaction with each stage of room treatment I've made. I now have much better sound stage depth and a lot less muddyness, especially with the bass which has really firmed up. Sure it would be nice to have the $$$ to be able to do professional sonic testing in the room but as Bob did, I just played it by ear. Fortunately I have yet to add any type of room treatment that I felt was undesirable,,,, everything I've done has always been pleasing to the ear and I can't ask for anything more than that for the wallet. Congratulations Bob with your room treatment success! 

Cheers,
Robin

[DanTheMan]

Great Bob!  You've given me the inspiration to get it done.  As I have no measuring equipment, I'm going at it redneck-like.  From the sounds of it, I'll have a tough time screwing it up too bad.

Bob, do you have photos of your work?

Is 703 available at a Lowe's or Home Depot?  Better yet at OSH?

Dan

[Bob in St. Louis]

Bryan - Yea, the OB thing will be interesting to conquer to say the least. My first "alignment" I did not put any panels on the side walls between the speakers and front wall (I only put them at first reflection points and rear wall). Since the whole point of OB involves the rear wave coming back to the listening position, I figured "sucking up" the sound wouldn't be good which is why I put all of the material between the speakers and rear wall. I'll listen to it like this for a while before I move things around.
As much of a difference this one box of material made it's hard for me to believe it could get any better, but I do plan on getting more material from you. Not sure what I want to do first; #1 Put double layers thick, three rows across behind the seating on the rear wall? (above and behind the computer chair between the rear surrounds) which would use half the box, or #2 concentrate on building the traps for the ceiling up above the projection screen like you mentioned. Or #3 Make single layer panels for first reflection points and leave a few panels for traps on the rear wall.
I may just play around and see what happens.

Robin - To answer your question; I had a lot.  aa Haven't you seen my photo of my "liquid acoustical enhancement products"? 
Yes, It would be nice to give Bryan a big check and say, "fix it", but these pesky things like mortgage keep getting in the way. 
It is good to hear that you continue to make gains by adding more material.

Dan - Yip, the redneck way certainly worked pretty well for me. Indeed.
Bryan stayed for a few hours after he dropped off the panels. I wish I'd have spread them out for his first impression instead of letting him listen to the "naked" sounding system. I was so happy with the way it sounded, but in retrospect, it's sounded anemic and bloated all at the same time. Sounds weird I know, but maybe Bryan or Ethan can better explain what I was hearing compaired to what I'm hearing now. 
- Yes, I will have photos. Hopefully tonight or in the am I'll take some photos and post them. I'm sure Bryan is curious as to where I've chosen their first (temporary) location.
- Not sure if the '703' is available retail or not (what is 'OSH'?). But I know of a guy that'll sell you some. aa
Just be sure to ask Lily first. You know about the WAF. 

Bob