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Acoustics/treatments in a large (34'x23'x8.5') HT room

624 Views 8 Replies 5 Participants Last post by  Ethan Winer
I skimmed through the "¿Que es mas macho - Bass Traps o EQ?" thread and feel a little overwhelmed by all the info there. They were dealing with a worst case type of "shoe box" room and were using a lot of panels and EQ to tame it.

Based on that, would it be reasonable to assume that a larger room, with lots angles and a generally odd overall shape would need less treatment?

In my case, my HT room is 34' x 23' x 8.5'. In some places the width is more like 20'. Everywhere the ceilings meets the walls, there are 45 degree angles. I'm having a hard time trying to figure out how many panels I would need and it I should treat the ceilings as well. The listening positions are in the middle of the room, so there is like 15+ feet to the rear walls.

Here are a couple of shots. Notice the starwell to the upstaris. Most of the floor is wall to wall carpet, but there is hardwood at the rear of the room in the pool area. The area around the bar is cork.


A shot of the pool area showing the 45 degree transitions between walls and ceilings. You will also notice that there are 45 degree angles where the I-beams were wrapped with sheetrock.


A shot from the front looking back towards the rear of the room:


And finally a shot from the sweet spot (occupied by the floor mounted projector):


I know my main speaker placements are probably not ideal, but I didn't have too many options. Also, the sub is that large black rectangle behind the left main speaker. The sub consists of 2 350 liter cabinets with 18" drivers, tuned to ~17Hz.

Anyway, I'm trying to figure out where to begin as far as treating this room. Placement of bass traps, etc. I just received a BFD and will be using it in conjunction with the Room EQ Wizard.

My initial thought was to add a pair of Mondo Traps in the rear corners behind the pool table. But this is like 34 feet away from the mains and subs, so will they be on any use at such a distance?

Will the 45 degree angles between all side walls and ceilings and I-beams benefit me or will those angle makes things worse? Would mounting bass traps on these 45 degree surface be worth considering?

Some general advice on how to treat a room this size with these various angles, etc. would be much appreciated!

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I would probably focus on treating those bare walls first, and the rear wall.

As for the bass, how is the bass response now?

> They were dealing with a worst case type of "shoe box" room and were using a lot of panels and EQ to tame it.

Beautiful room... Nice system setup. Your 4-legged buddy is saying turn it down ;)
Originally Posted by ChrisWiggles
As for the bass, how is the bass response now?
Well, I'm in between drivers at the moment. I'm expecting a pair of TC Sounds PA-5000 18's early next week. They will be replacing a pair of JBL 2245H's. The bass was somewhat boomy, and dialog during movies could be difficult to hear at times, so I definitely have some issues to work out.
Originally Posted by Ethan Winer
The short version is:

* Broadband (not tuned) bass traps straddling corners.

* Mid/high frequency absorption at the first reflection points on the side walls and ceiling.

* Some additional amount of mid/high absorption on any large areas of bare parallel surfaces, such as opposing walls or the ceiling if the floor is reflective.
Thanks Ethan! This gives me something to work with.

How do I "straddle corners" with bass traps? Can I use wall anchors in the walls and some sort of spacers? I'd rather look at permanently mounting everyting as opposed to using stands.

How do I find my first reflection points on the side walls and ceiling? Is this the trick where a buddy slides a mirror along all surfaces and you sit in the main listening position and anytime you see a main speaker in the mirror, you found a spot in need of treatment?
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Originally Posted by max190

Beautiful room... Nice system setup. Your 4-legged buddy is saying turn it down ;)
Thanks Max! At some point I plan to get some matching HT furniture, but yes, the room itself turned out real nice!

Rufus (the german sheperd) doesn't really mind music, but he was confused about what in the world I was doing walking around with some apparatus that made big flashes.
Nice space.

Looks to me like you don't have a lot of room in the front corners for straddling panels. I'd consider some 6" thick panels floor to ceiling flat against the front wall. That will give you some good broadband and also help with the front wall reflections a little. Lastly, it will help somewhat with SBIR from the close proximity of the mains to the front wall.

After that, I'd agree to get some absorbtion on the bare side walls to help with reflections and general decay time.

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