# First dedicated room, needs treatment



## Lunchietey (Jul 11, 2012)

Hi Everyone!

I'm a long time stalker of these excellent forums and have spent MANY days reading and reading!

I have moved into my first non-rented home about 6 months ago and have finally started planning my dedicated ht/av room!

The room(i havent measured) is approximately 16ft long, 11-12 ft wide and 8ft ceilings. It is hard floored(wood on concrete) brick/plaster walls with windows at one end(two narrow but tall windows) with an opening at the rear right corner on the side wall which will likely end up with a door. The stud wall will have an AT screen(diy) with the LCR speakers behind(probably OB fullrange) and subs below. The whole black section of the wall will also be at cloth with fibreglass behind to absorb reflections at the front.

This dimention is after I build a stud wall for the screen etc. So essentially a rectangle that is nice and reflective!

I was originally going to simply cover all walls with 2" thick fibreglass mounted to large frames and cloth stapled over to 'tile' the room but I believe this is a bad idea as it will kill all life out of the room but not do much to stop boomy bass? What about if I did the panels but only had half of them with fibreglass and the others with nothing inside to keep the 'look'? 

Should I just build and install all of the cloth covered frames and tune to taste?

I'm guessing a good place to start is have heavier damping at the front half of the room, and less at the back to keep ambience. Is this a good idea?

The two rear corners will also have two floor to ceiling wedge shaped columns which will be bass traps with concealed rear speakers, and two matching side columns containing bass traps and side surrounds.

*EDIT* also there will be a large thick rug on the floor eventually!

Help!

Thankyou!


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## HopefulFred (Jan 20, 2011)

Congratulations on your new space - I hope it turns out great - I'll be looking forward to your posting great results, so I can copy them! 

The suggestion I would make is that you not limit yourself to the positions of your subs. A few corner bass traps is probably a good idea, but won't have the influence that proper placement can. This lecture presented by Floyd Toole is very informative. http://www.harman.com/EN-US/OurComp...ents/White Papers/LoudspeakersandRoomsPt3.pdf

Fred


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## Lunchietey (Jul 11, 2012)

Oh yeah, there will be multiple subwoofers, behind the screen I can install and move them around as I need to. I will only use the one to start with probably off to one side or something and potentially add more around the room. The previously mentioned columns could be modified to house a sealed 12" or something. Very interesting read in that link too, thanks! I can also add bench style subwoofers along the sides, a large flat one under the couch or even a coffee table style on the side etc.

I was even considering one or more IB subwoofers in the ceiling for a completely flush and speaker free space. I have no real limitations as far as space goes, it's my house so I can do as I please!
*edit*

I should mention there are 3 kids! SO I'm trying to hide as much as possible from little hands! All of the av equipment will be behind the screen accessed from a door leading to the other lounge area, and an infra-red repeater installed under the screen. Any subwoofers and speakers installed in the listening area will be concealed in columns etc. Even the black cloth i'm using on the wall panels/screen surround is extremely tough and used for (of all things) underground dampcourse but seems to be mostly acoustically transparent. Only subwoofers will fire through this material. Surrounds will have standard black speaker cloth inlays.

The black fabric looks kind of like automotive carpet but is easily seen through when held up to light. The main speakers will fire through an AT screen. Its called GEOFAB or something, and is EXTREMELY CHEAP!


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## bpape (Sep 14, 2006)

Even 1/2 the room in just 2" thick is too much thin and no bass control. Nothing wrong with using empty frames to keep the look - just make some of them more like 4-6" deep. Won't look any different once they're up.

Bryan


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## Lunchietey (Jul 11, 2012)

As mentioned there will be some thicker bass traps in corners etc 

What about 4" deep frames all around with some containing 2" fibreglass spaced 2" off the wall? Or does it need 4" thick fibreglass?

My house is very quiet(double brick cavity wall, ceramic tile roof well insulated) and I live in a very very quiet street so I'm just looking to have a very quiet room as much as possible. As it stands, the house is quite reverberant due to brick walls and wood floors with open plan design.

I can build fairly deep pockets in the screen wall in between speakers etc which could act as low fequency absorbers? Do those NEED to be in corners?:huh:


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## bpape (Sep 14, 2006)

Corners are an efficient place for bass control since they're at the end of 2 boundaries. 

My point previously was 2 fold.

1. Not enough thicker absorption.

2. WAY too much overall absorption of the wrong kind (too thin).

2" with a little gap behind it at the reflection zone would be great. The rest of the side walls, not so much. Front wall - 2" with no gap is fine.

Corners - I would do the front ones - minimum 4" panel straddling. If not straddling, go maybe -8" thick.

Rear wall could use 4" with a bit of a gap behind it. Use some sort of thin membrane on the front to minimize higher frequency absorption here if desired.

Bryan


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## Lunchietey (Jul 11, 2012)

Ok, I think I get it!

I'll line the walls with the panels I hope to make(large panels with bevelled edges) all 4" deep along the sides. At the main reflection points I'll do the 2" batts with 2" space behind. I'll line as much of the front wall as I can with 2" batts behind the cloth(probablly 50% of the area) and make some bass traps in the corners at the front to begin with. I'll build speakers into these panels for surrounds(or maybe use 2 pair minimus 7's I have as they would fit in 4" depth I think?)

The paper backed batts sound like a great idea for the back wall at 4" thick(can only cover half of this wall as it has 2 windows that will have heavy blackout drapes) and I guess go from there?

One thing I didnt mention as to the panel idea is that this whole cinema could be removed back to an empty room and simply fill a few holes in the wall. All of these large panels will just hang, and the screen wall will only be fixed to certail points and be removable if I need the space again! But at least the vast majority of the room will be black, and acoustically treated this way! As I mentioned before, theres already 3 kids, but the missus wants a girl so bad we may have 4 soon!

Thanks so much for that advice, I probably would have done a big noob mistake and done 2" everywhere!


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## Lunchietey (Jul 11, 2012)

Ok, plans may change a little.

The 'L' shaped area that was being divided by 2 has been rotated so the narrower side will be the HT, and the short square side will become another bedroom(she WANTS that little baby girl!)

So the theatre will now be about 19ft long but 10 1/2 feet wide. I now no longer have a seperate av/behind screen cupboard with virtually unlimited speaker box volume. The screen will still be AT but only have a depth behind the screen of around 150mm. So I'll build in some fairly 'conventional' speakers and subwoofers.

The rear wall(rear left) has an angled section(fridge alcove/kitchen is behind this) and the equipment will be in the rear right corner. I'll just install a lockable vented glass doored cabinet there with the projector above.

I'll probably stick to the original plan, but start with a bass trap in the rear next to the av rack as the screen will be 'almost' as wide as the front wall no leaving much room for any bass traps. 4" thick pads will be on rear walls(paper faced) and the first 6ft of the side walls. I'll have to treat from there!:scratch:


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## bpape (Sep 14, 2006)

A rough top view sketch now that you have your 5 posts would be nice to see.

Bryan


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