Help with room acoustics

**jdeanmc** · **02-11-09, 11:29 PM**

I need some help treating my basement Ht room.
First of im the same jdeanmc who has worried everyone senseless on the rew forum,but after many,many posts and with the help of alot of very patient,intelligent people,i have finally gotten my setup sounding much better.
Now im at the point of tackling room treatments.I dont know what all info is needed so i may include more than whats neccesary,if so,sorry in advance.
My room is 21.3x21.3 with 8 foot 4inch ceilings.side walls are tongue in groove,studs,insulation then concrete block,front wall is tongue in groove over insulation then sheetrock(the other side of this wall, is the undserstairs room and the walk that leads up the stairs)back wall is tongue in groove,insulation,studs then pegboard(the back side of this wall is the basement garage)
The problem areas i have as far as room mode calculators is that the left corner is actually 4 feet 2 inches back from the front wall(the staircase)the right corner has the door for the understairs utility room,the rear left has a 4x8 restroom that protrudes into the room and the rr right corner has door leading into garage!!! so corner treatments are pretty much out i guess.
The ceiling is uninsulated on "scissor joist"which then becomes the hardwood floor of the great room upstairs.
My "ears"at listening position are currently 12foot 6 inches from front wall,8 foot 7 inches from rear wall,this keeps me slightly in front of the restroom on the left.
Equipment list...
Klipsch rf-3 II fronts,klipsch rc-3II center,klipsch cdt 5800 rear surrounds(in ceiling)HSU vtf mk3 ho(currently turbo removed)and hsu mbm12 centered behind sofa,Yamaha rx-v1800 receiver and bfd 1100.
You can see my feeble attempt at first reflection point traps as well as 4 inch bass traps.I want to replace these with some sort of built in columns,with the material made into this,possibly solid up a few feet,we have cats and i dont want these getting "climbed"hence the grills removed on all speakers in the pics(this wasnt a vanity issue!)
I would like to move all equipment into the utilty room(i have the rf expander with univesal remote)as well as add projector and screen where the tv is now.
What are options as far as placement,# of panels,ideas on building columns etc.
I want best bang for the buck and dont want to build anything thats not needed.
Im lookin for the best sound quality that i can get without redoing the room as far as adding walls,while adding touches that wont look like a recording studio.
All suggestions welcome.

**bpape** · **02-12-09, 07:07 AM**

Well, that's a lot to accomplish and a lot of restrictions to go with it. Something is going to have to give a little bit.

Bass control is very much needed - and to fix frequency response anomolies, it will need to go where it will help - not just somewhere in the room. Candidates: Behind the main speakers, in the corners, centered on the rear wall of the room.

I'd consider pulling the main speakers away from the front wall to minimize boundary interference issues.

One possibility is to build a soffit around the perimeter of the room to act as a large broadband bass absorber. It's not going to fix all the issues but it's a good chunk of the general control you'll need in a basically square room.

Bryan

**jdeanmc** · **02-12-09, 09:34 AM**

Quote:

bpape wrote:

Candidates: Behind the main speakers, in the corners, centered on the rear wall of the room.
I'd consider pulling the main speakers away from the front wall to minimize boundary interference issues.
Bryan

Hi Bryan,
Thanks for your response.
As you can see from the pics i have the mains as far apart as i can get them,without being in a walkway on the left and in front of the door on the right.this puts the mains about 8 inches closer to each other than i am from the center(trying for the triangle thing)i could move the mains a few feet closer to each other and get them in front of the bass traps,id have to swap places with the right front and the equipment rack.i could then pull them away from the wall a little more,as they are now i have to have them that close to wall to be able to get in front of them,(door/walkway again!)Though after numerous attempts im finally happy with the imaging from left and right mains,i sit at the right side of sofa and finally the right speaker doesnt seem so dominate to me in stereo mode.Ypao in the yamaha receiver may correct for this??
I do have the rear wall that i can do anything with however its not really centered behind the listening position as i have that restroom in the right rear corner.
The corners are a problem as it seems they are all "active corners with doors or walkways?
Would the front or rear wall be more desired with the bass traps?

P.s.I have followed your posts in helping another fellow Alabamian(Birmingham.i think)and thats what got this all going again for me!!
i had spoken with you months ago,then this all fell on the backburner as ive been playing with the rew/bfd for months now.I havent totally ruled out std traps,but really wanted to do some sort of built in's or columns or such.
Thanks again

**bpape** · **02-12-09, 09:50 AM**

I wouldn't move them much closer together. It think you're OK as is. Doing something behind them would certainly help though.

For the rear, if you can get anything in the back that has some decent thickness to it, that will also help.

My primary suggestion still stands about building a false soffit.

Bryan

**jdeanmc** · **02-12-09, 10:21 AM**

Please don't think im dismissing your suggestions,im not,but the false soffit thing(which im sure will make a huge improvement)brings a whole new set of problems,in ceilings would all have to be relocated,i dont know what id do around the opening up the stairwell,etc.so if i can improve without this id rather explore other avenues,if you tell me "nothing else will work as well!now get out the hammer and nails and stop whining!!"then thats another matter!
I could move the mains about a foot in closer on each side and possibly move the traps out another few inches to try to get the mains in front of the traps,i couldnt do much more as id cover up the light switches(this is what i run into,every solution brings another problem)would i want the 4 inch there and 2 inch on first reflection points?these are oc 703,one sheet on two and two sheets doubled up on two.they have a wooden frame behind that keeps them about an inch from the wall(airgap)then a 1/2 strip as a hanger so the panel is about 1 1/2 inch from the wall. Did however(before i read otherwise)ripped the foil face off all panels!

can build more for rear wall but at some point ill have to disguise these,frame them in with molding around build them into panels or something,i really want the cinema motif after the projector is added.

**bpape** · **02-12-09, 10:35 AM**

I understand the desire for the look which is why I recommended the soffiting as opposed to a lot of panels hanging on the wall. I really don't see any other way to get significant bass control into the room. Every other place has something in the way.

Behind the mains, 2" will do fine.

Bryan

**Kal Rubinson** · **02-12-09, 10:49 AM**

First, I do not see any "bass" panels as it seems your on-wall panels are too small/thin to be effective in the range that is your problem.
Second, with a 21' square room, the modes gang up on you as you can see from the measurements.
Third, the soffit does not have to be on the wall/ceiling angle. It can be on a wall/floor angle (see attached) but a typical wall/wall angle, as well.

Kal

**Kal Rubinson** · **02-12-09, 10:54 AM**

First, I do not see any "bass" panels as it seems your on-wall panels are too small/thin to be effective in the range that is your problem.
Second, with a 21' square room, the modes gang up on you as you can see from the measurements.
Third, the soffit does not have to be on the wall/ceiling angle. It can be on a wall/floor angle (see attached) but a typical wall/wall angle, as well.

Kal

**jdeanmc** · **02-12-09, 03:20 PM**

well now,i do like the looks of that.How many walls do you have these on?
maybe i need to rethink this and put up enough on wall panels to make a difference,then when i see what works,i can pursue going a permanent route,as far as trimming these in to hide them?
Would it be possible to get enough on wall panels or front wall lower soffit or rear only corner traps to be effective?
I really would like to keep the whole room perimeter soffit as a last ditch effort thing,i dont want to seem lazy but i dont want to get that "permanent" unless all else fails.

**bpape** · **02-12-09, 03:33 PM**

Any soffit you can do will help. Even if you just do across the back wall and make it say 12" deep and 6" tall - that's a great start.

**jdeanmc** · **02-12-09, 03:44 PM**

would doing it floor/wall on the rear wall be as effective as ceiling/wall?again i hate to have to move the rear in ceiling speaker and leave a big ole hole.any construction tips?material,insulation etc?

**bpape** · **02-12-09, 03:54 PM**

Not sure what you want me to tell you. Will it work on the floor? Absolutely. Will it be AS GOOD as on the ceiling - probably not. Where Kal has it, up front, the floor helps with SBIR issues.

How many absorptive things do you see on the floor and half way up? Lots. Chairs, people, etc. How many do you see up high in your room? None. Spreading absoprtion helps a lot.

Now, if you don't want to move the rear speakers (which shouldn't be back by the corner anyway but that's another story) then you can do the sides - but you want to do as little as possible so I recommended the rear. Unfortunately, bass control isn't accomplished with small amounts of small treatments. You're talking about waves that are 20 FEET long or more.

If there was a way to make something very small and unobtrusive that would deal with bass issues, I'd love to have it. I'd patent it in a heartbeat and retire on the riches it would bring. Unfortunately, mother nature has other ideas.

**Kal Rubinson** · **02-12-09, 04:08 PM**

Quote:

jdeanmc wrote:

well now,i do like the looks of that.How many walls do you have these on?

Only the front but I have other traps in the rear corners.

Quote:

I really would like to keep the whole room perimeter soffit as a last ditch effort thing,i dont want to seem lazy but i dont want to get that "permanent" unless all else fails.

I got the panels from Bryan Pape and here's another view to show you the mounting. 3" brads connect the panels. (I do not think of it as construction or permanent.) I subsequently removed two of the three "filler" panels.

**jdeanmc** · **02-12-09, 04:41 PM**

Quote:

bpape wrote:

Not sure what you want me to tell you. Will it work on the floor? Absolutely. Will it be AS GOOD as on the ceiling - probably not. Where Kal has it, up front, the floor helps with SBIR issues.

This is exactly what i wanted you to tell me,hence the question"would the rear wall/floor be as effective as the rear wall/ceiling, as Kal stated "they can be on the floor/ceiling angle,wall/wall angle or wall/floor angle"i just wanted to know which would be the most effective "thanks,i think you answered that

Quote:

bpape wrote:

Now, if you don't want to move the rear speakers (which shouldn't be back by the corner anyway but that's another story) then you can do the sides - but you want to do as little as possible so I recommended the rear. Unfortunately, bass control isn't accomplished with small amounts of small treatments. You're talking about waves that are 20 FEET long or more.

The rear speakers arent in the corners they are in a semi circle fashion with the one rear(6.1 setup)closer to the rear wall than the left and right surrounds.i wanted to avoid moving this if there was any alternative which would be as effective,i think you answered this as well so Thank you
Dean

**bpape** · **02-12-09, 06:24 PM**

Sorry - I was a bit busy earlier but wanted to respond to you. Didn't mean to come across as short. If we can do some on the side walls, that will help just fine and as well as the rear most likley unless the seating is very close to the rear wall.
Bryan

**jdeanmc** · **02-12-09, 06:41 PM**

Quote:

bpape wrote:

Sorry - I was a bit busy earlier but wanted to respond to you. Didn't mean to come across as short. If we can do some on the side walls, that will help just fine and as well as the rear most likley unless the seating is very close to the rear wall.
Bryan

Not at all.I understand and i appreciate all your help.
The seating is about 8 1/2 feet from rear wall,so im ok on room there.

Please let me apologize for my ignorance,im just overwhelmed with the treatment thing as i really dont want to muck up the room too much and i guess everything at this point seems drastic.It was the same when i started the rew/bfd quest but once i got my head around it it wasnt too bad.
Thanks again Dean

**bpape** · **02-12-09, 06:57 PM**

If you have that kind of distance behind you then doing the sides will work fine - and give you more overall surface area to deal with.

Bryan

**hjones4841** · **02-13-09, 05:33 AM**

Quote:

jdeanmc wrote:

P.s.I have followed your posts in helping another fellow Alabamian(Birmingham.i think)and thats what got this all going again for me!!

You talking 'bout me?

Follow Bryan's guidance, he is very knowledgeable. I was skeptical about traps at first, but now I am a fanboy (if at age 59 anyone would still call me "boy":

).

I went with pre-fab from GIK, but others have done well building DIY traps. Keep in mind that most rooms of yours and my size take lots of trapping. The performance improvement when I went from 2 to 5 Monster traps was HUGE.

If you don't have a local source, there is a place in Leeds that makes mineral wool that a friend purchased from. I can get the name of it if you wish.

**jdeanmc** · **02-13-09, 10:14 AM**

Quote:

hjones4841 wrote:

You talking 'bout me?

it WAS you.
Im in Decatur,right by 65.
I have followed your posts and have now decided to tackle room treatments.I do know of a local supplier that carries the OC 703.
Im not totally sold on the Diy route,though that option is still open.Its just that my wife has sold me on the idea to try to keep things "clean"looking.As i scan through Home theater magazines,the trappings and equipment as almost never visible,I plan tonight to move the equipment rack to the understairs room and finally use the rf expander doo hickey i purchased about a year ago!
Now my dilemma is how to trap the room and "conceal"to some degree the traps.I dont want to go overboard but id like to get the traps in place where they make the most difference and then frame them in withcrown molding or something.Im still trying to decide what to do?

**jdeanmc** · **02-13-09, 11:20 AM**

Quote:

bpape wrote:

Any soffit you can do will help. Even if you just do across the back wall and make it say 12" deep and 6" tall - that's a great start.

o.k. After letting this sink in and checking a few things last night,i think i can manage this.
The rear center speaker is about 13-14 inches from the rear wall,so i could come out from the rear wall around a foot total,i could come down maybe 10 inches (there is a door back there)

**jdeanmc** · **04-01-09, 05:40 PM**

Hi Brian,Kal etc...
Been a while since ive posted as ive been experimenting.Could you guys tell me if im doing anything reasonable?
I moved my 4 inch panels with 2"air gap to the rear walls and took (9) 12"x12"x 40" boxes and filled them with 2 layers of r25(8 inches thick each)i stacked 2 into each rear wall corner and lined the others from corner to corner along the top ceiling to rear wall angle.(i know this sounds ridiculous)but is it effective?
My ringing doesnt seemed to have changed any. but boy it does sound better!
Now my wife will never have this long term so i will have to build something to cover these up if they stay,what else should i do to improve ringing?i can keep stuffing boxes with insulation and placing them around if that'll help.
Basically i would like to get the room sounding as good as i can even if that means boxes everywhere,so i can see what my room could sound like, then ill have to make changes to make this more appealing looking.
Dean

**bpape** · **04-01-09, 06:02 PM**

Sure. What you did is replicate a decent broadband bass absorber in the corners and helped kill the nulls off the back wall.

Can you be a bit more specific as to what you mean by ringing? What frequency range?

Bryan

**jdeanmc** · **04-01-09, 06:53 PM**

sorry Brian
The first post above shows my waterfall graph(though a few things have changed,moved subs behind sofa as per pete at hsu research as well as moved sofa 2 feet back)however the 25 hz and down ringing remains the same as above.
Thanks Dean

**hjones4841** · **04-01-09, 07:41 PM**

Quote:

jdeanmc wrote:

My ringing doesnt seemed to have changed any. but boy it does sound better!

Same experience as me as well as others, I am sure. Minor changes in the graphs for the first round of trapping simply don't correlate with the improvement in sound, which is far greater than the differences in the waterfalls suggest.

For me, there was a slope off in cost/work/benefit as I added more. By this I mean that the first traps make the most difference. Once you get hooked on the improved sound quality, you are convinced to add more. Then, the graphs look prettier, but the improvement in sound is incremental and not as great as the first ones. At least that is what happened in my case.

**bpape** · **04-02-09, 07:30 AM**

Getting decay times down below 25Hz is pretty tough realistically. If the overall decay time is still about the same from 80Hz down, you can work with some very thick absorbers to help the entire range.

If your FR is about the same from 40hz down, IMO, you have either something amiss in the measurements or the tuning of the sub is putting out too much down very low (nice problem to have). If you have the multiple ports, you might try using a lossy plug in one of the ports.

Bryan

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