Room treatments/alterations?

[Morik]

Hi guys,

So I have this layout (hmm can't post images... that is problematic... basically rectangular basement, 25' wide, 16' long on one half, 18' on the other. The 18' long area is for HT. There is a column roughly in the middle of the entire room, between the 18' area and the 16' area. Other than that the 2 areas are open to each other. The ceilings are about 7'9' high in most of the basement, but from front to back by the column they are only 6'11 or so.

The walls are all drywall over concrete (with normal wooden framing), the floor is tile over concrete with no special stuff, not floating or anything. There is a bunch of computer stuff & several plastic-top tables over on the other side of the basement.

I have several concerns:

With the clap test, I don't hear a long echo, but there is some echo. I don't think its horribly bad... I plan to put down a large rug in the HT area, which will likely help some. Would some sort of wall hanging help on the other side of the basement? (My wife won't go for normal accoustical treatments, but something like a tapestry or some other reasonable looking clothy thing could work...)

My larger concern is with the open area to the left of the front left speaker (which will just have open area for about 12 - 16' on the left of it).

The problem is that I have the Mirage OMD-15 floorstanding speakers (and OMD5s for surrounds, and OMDC1 for the center). The OMD series of speakers works off of 70% reflected sound, 30% direct. The manual states that the first point of reflection for the speakers is very important for sound quality. My wife does not want to build out a full wall there... she said a half-wall may be ok, but not positive yet.

I'd like to determine if a wall (or something) there would be very helpful, and if so, how high it would need to be. I plan to test by holding up a large piece of plywood or something similar in the area... but any other thoughts would be nice!

Thanks for any help!

 

[Morik]

A couple more questions while I'm at it:

- There is a small window, somewhat high up along the wall. I'd prefer to keep it blocked off anyway to keep light out... to also keep my subwoofers from being louder through the glass than through my house walls, would stuffing the window hole (approx 1' high by 2.5' wide by 2 feet deep, but I could be wrong.. can measure tonight if it matters) with that fluffy insulation material suffice? (and then I'd put a small velvet curtain or something over it so it doesn't get the WAF-smackdown) I took a look at accoustical foam... would that be better for blocking the low frequencies? (I'd have to just mush it up and stuff it in there, which is why I was thinking just regular fluffy insulation foam)

- Are there any non-drastic changes I could make around the ceiling to keep the subwoofer noise down a bit on the floor above? I can hear footsteps above pretty clearly, so I imagine its going to be problematic. (Though I don't want to stop my Mirage speakers from getting good reflection from the ceiling either, so...)

 

[Morik]

Here is a rough floorplan if that helps:

 

[Glenn Kuras]

- Are there any non-drastic changes I could make around the ceiling to keep the subwoofer noise down a bit on the floor above? I can hear footsteps above pretty clearly, so I imagine its going to be problematic. (Though I don't want to stop my Mirage speakers from getting good reflection from the ceiling either, so...)

There is no easy fix to your problem and to be honest you would need to build a new ceiling that would make it pretty low.
As far as treatment there really is not much you can do if the wife is not going to let you put up some treatment. Is there a reason she is against panels on wall? If so you could make panels with art on the fronts. The process is called dye sublimation, which dyes the image onto the fabric which will not mess with the acoustic properties. Here is a image of my own I did for my condo.

 

[Morik]

I've been slowly talking her into panels... I'm gonna wanna put up a bass trap in the upper right corner at least, probably bottom left too. (I have some drawers in a sparse IKEA frame in the upper left corner, so can't really put anything unless I moved them, but there isn't much room to move them around...)

I'd want to put some smaller bass traps in a few other areas, like that upper left corner, and on some corners formed where the ceiling lowers near the column. (Though I haven't brought up foam, as she will probably think this is really ugly... not sure what other small bass traps there are out there)


My main worry though is that open area to the left of the speaker... anyone have any experience with the OMD15s? Any idea how big an effect I'm looking at by not having it near a sidewall?

 

[Glenn Kuras]

My main worry though is that open area to the left of the speaker... anyone have any experience with the OMD15s? Any idea how big an effect I'm looking at by not having it near a sidewall?

Having a open area can actually be a good and bad thing. It is good as it is not letting any early reflection hit you, but bad if the other side has a reflection which will mess up imaging. The cure is to put absorption (that word you did not what to hear ) on the wall with the reflection point to balance the summitry out.

Glenn

 

[Morik]

Having a open area can actually be a good and bad thing. It is good as it is not letting any early reflection hit you, but bad if the other side has a reflection which will mess up imaging. The cure is to put absorption (that word you did not what to hear ) on the wall with the reflection point to balance the summitry out.

Glenn

So even with omnipolar speakers, its fine not to have the sidewall to reflect off of?


Sounds like putting in 2 large fiberglass type bass absorption corner panels would be nice for evening out response... I could maybe try to get another panel for midwall on the other side of the room from the HT.


I assume a large rug in the HT area, along with 2 corner bass traps, a mid-wall absorption panel, and maybe some corner traps (if I can find ones that pass the WAF test), would help with echo? My room is moderately echoy...

(I think putting a thick curtain over the open entrance to the stairwell may help too, and will at least keep a little more sound from leaking upstairs...)