Acoustic Effects of Room width Closet?

PLMONROE · « **on:** 12 Apr 2007, 04:29 am »

I suspect this may not be uncommon however I have been unable to find any real information. I am hoping the experts on this forum and others far more knowledgeable than I will be able to give me some insight. You see I do not really know what size room I have.

My sound room is a converted upstairs bedroom. I have my speakers along the short dimension of the room about three feet in from the front of a full room width open closet. Along that end of the room is a closet running the full width of the room. It had two 4 foot wide folding wooden doors, six foot eight inches high which I removed. I have two huge equipment racks in the former closet area housing all my equipment. The height of the ceiling is nine feet and the width of the room is twelve feet eight inches. The length of the room proper is sixteen feet eleven inches to the wall of the closet. The closet depth (including the framework) is two feet eight inches to the back wall. The partition separating the room and closet extends down from the ceiling by two feet eight inches. The partitions on the sides are slightly unequal; the partition on the left comes out one foot ten inches and the one on the right comes out one foot four inches. From the edges of these are the two four foot wide openings (where the doors formerly were) with a one foot seven inch divider between the two.

The obvious answer to my problem is to remove all the framework and have one nice simple room, 9' high, 12.75' wide and 19.ft 7inches long - right? WRONG! From the point of view of my better

half this does not even approach being an option - now or ever!

So????

1) So do I treat this as a 17' room or a 19 1/2" room (or maybe something in between)?
2) Adjacent wall corner treatment -- do I place absorption in the corners of the room and side closet partition or in the back wall junctions of the closet? Or perhaps both?

3) Wall to wall to ceiling corner treatment. Do I need to treat six upper corners, or just four (and if four - which four)?
4) I have two ASC 16' super traps. Do I put them in the closet, or in the room, or - no no we won't go there!

5) I understand its best to be seated 38% out into the room but which measurements should I base this upon etc.,etc.,etc.
6) I am sure there are all sorts of issues I have not considered

Just how should I undertake setting up this room for good 2 channel sound ?

Paul

tanchiro58 · « **Reply #1 on:** 12 Apr 2007, 12:20 pm »

Hi Paul,

I got one small closet to my right speaker. Since I open it up the soundstage is getting bigger with more musical sound.

You got to go to each corner of your room and clap your hands if you hear echos everytime you clap there is a place (between the ceiling and two that stand upright walls) you should put the corner treatment (Echobusters or Eight Nerves) for each corner. Then you should place something like absorption foam behind each speaker. Other walls I place canvas pictures to absorb bouncing sounds. I have two small ASC tube traps too and they are placed in each corner to the side of speaker. Good luck.

bpape · « **Reply #2 on:** 12 Apr 2007, 01:33 pm »

Can you post a quick sketch of the room so I can better visulize what you've got going on - being a little dense today.

Bryan

PLMONROE · « **Reply #3 on:** 12 Apr 2007, 07:21 pm »

I went to paint and drew a sketch of the room for you to see, however even after over an hour of effort I can't seem to get this section of the forum to allow me to cut and paste it here. Not sure what I am doing wrong, probably someting basic.

Sorry for my computer ignorance.

That being said -- basically what I have is a room about 19.5 feet long that has had 2.5 feet of one whole end framed off into a full width closet. There were two folding doors, each four feet wide, made of wood leading into the closet which I removed. So I now have the entire closet space almost entirely open into the rest of the room. I sit at the far end of the room about 3 feet from the back wall. The speakers are at the other end about 3 feet back of the openings into the closet space

bpape · « **Reply #4 on:** 12 Apr 2007, 07:24 pm »

Put the image in your 'gallery' here. You can easily create your own. Then link to it from your post.

Bryan

PLMONROE · « **Reply #5 on:** 13 Apr 2007, 04:52 pm »

http://www.audiocircle.com/gallery/albums/userpics/11020/thumb_SOUND_ROOM.bmp

Here 'ya are

PLMONROE · « **Reply #6 on:** 13 Apr 2007, 06:22 pm »

Gee, thats tiny. As soon as I figure how I will get it up here from my gallary where it will be bigger

bpape · « **Reply #7 on:** 13 Apr 2007, 06:25 pm »

ROTFL - yeah, that's kind of tough to read

Bryan

Red Dragon Audio · « **Reply #8 on:** 13 Apr 2007, 11:08 pm »

PLMONROE · « **Reply #9 on:** 14 Apr 2007, 01:01 am »

Ryan, Thank you, thank you, thank you. I tried without success for a couple of hours to get that up! (I guess computers are just not my thing -- wrong genration perhaps)

Paul (aka 1SrCitizen)

PLMONROE · « **Reply #10 on:** 14 Apr 2007, 01:53 am »

Ok, now that Ryan was kind enough to put up the sketch of my sound room and you all can see it without getting eye strain how is it best treated? Recently I completely rearranged this room, which was formerly set up for home theater, to dedicate it to two channel audio. Speakers are Brian Cheny's new RM-V60s (see VMPS Forum). These are a unique design with ribbon planers in an open backed V configuration. They are probably more dipole in sound propagation than anything else. Here are the acoustic treatments I presently have on hand with which to work:

22 RPG Skyliners
2 ASC 16 inch Bass Super Traps
4 RealTraps
2 Floor Standers

I am considering purchasing two more 16 inch Bass traps with the thought of stacking them, however this may not be the best way to use them?

Presently 6 skyliners are an the ceiling at the first reflection points, the 2 floor standers are along the side walls with a RealTrap behind each located at the first reflection points and 3 skyliners are on the rear wall behind my seating position at head height. However from what I am reading on this forum I may be getting little effect from them since they are only three feet or so behind me?

Suggestions from a local sound establishment included taking
the 4 RealTraps and covering them with plastic to make them more reflective, then mounting two RPG units on each and hanging them in the four upper room corners.

The room is constructed with sheet rock on walls and ceiling. The wall with windows (heavily draped) is an outside wall with bat insulation and brick on the outside. This is also the case of the back wall of the closet. The wall to the rear and left of the seating position are interior walls but have insulation in them. The ceiling has 24 inches of blown insulation over it and the floor is heavy carpet over light wight concrete.

So where do I place treatments to best use what I have on hand, and is there anything that should be eliminated or added to what I presently have to get the best sound from this room? Thanks.

Paul

Red Dragon Audio · « **Reply #11 on:** 14 Apr 2007, 02:26 am »

Hey Paul,

Happy to help!

bpape · « **Reply #12 on:** 14 Apr 2007, 02:42 am »

I'd run it with the closet doors closed and plan on things based on the shorter dimension. You'll still want some basic absorbtion in the closet just to keep resonances down.

IMO what you currently have is VERY short on bass control - and general decay time control. You have tons of diffusion and little to no absorbtion. Consider permanent/portable treatments that would let you treat all 4 vertical corners pretty much floor to ceiling.

While the 16" tubes are nice, they're not going to reach very deep into the bass. To do that with tubes, you need the BIG ones. A more solid triangular type absorber that will tuck right into the corner will be more effective down deeper.

Leave the Real Traps alone - they work very well as designed. Try them straddling the wall/ceiling intersection in various places (centered on the front and rear wall/ceiling intersection, 1/2 and/or 1/3 of the room length along the side wall/ceiling intersection, potentially as a replacement for the 4" I mention just below, etc.)

I'd also consider some 4" or so thick absorbtion on the rear wall of the room behind the listening position.

Lastly (not sure the drawing is to scale), the seat is way too close to the back wall. Try it about 38% of the room length from the rear wall. You may find in this room that listening in a more nearfield setup may be preferable.

Bryan

Ethan Winer · « **Reply #13 on:** 14 Apr 2007, 03:34 pm »

Paul,

> Suggestions from a local sound establishment included taking the 4 RealTraps and covering them with plastic to make them more reflective <

As Bryan said, you're not going to improve on our trap design by covering them with plastic!

I also agree with Bryan that what you need most is thick broadband absorption directly behind your head. Sitting right in front of a wall is where the peaks and nulls are worst at all frequencies.

--Ethan

PLMONROE · « **Reply #14 on:** 14 Apr 2007, 04:04 pm »

Quote from: Red Dragon Audio on 13 Apr 2007, 11:08 pm

Quote from: bpape on 14 Apr 2007, 02:42 am

I'd run it with the closet doors closed and plan on things based on the shorter dimension. You'll still want some basic absorbtion in the closet just to keep resonances down.

Unfortunately all my sound and home theater equipment is on two built in equipment racks in the closet area and I have ventelataion problems with the doors in place. A side result of the large openings into the closet area is I don't know which length dimension to use in calculating that room node, that of the room proper or that of the room plus closet. More immportantly what sort of basic absoption for the closet area would you suggest???

Quote from: bpape on 14 Apr 2007, 02:42 am

IMO what you currently have is VERY short on bass control - and general decay time control. You have tons of diffusion and little to no absorbtion. Consider permanent/portable treatments that would let you treat all 4 vertical corners pretty much floor to ceiling.

While the 16" tubes are nice, they're not going to reach very deep into the bass. To do that with tubes, you need the BIG ones. A more solid triangular type absorber that will tuck right into the corner will be more effective down deeper.

I agree. At present only a few RPG units are presently installed. Those are the few on the ceiling and behind me on the wall, the rest are boxed up. The question is, once I install adequate absorption how many of these are appropriate to my needs and where should they be positioned? Or for whatever diffusion needs I might have, would Alans products perhaps be a better choice?

Bryan, I notice you did not mention the potential use of any tri-corner traps such as those by ASC, RealTrap, Eightherve, etc. I presume that might be because floor to ceiling, more solid, triangular absorbers you rerfer to would take their place? I was not sure exactly what you had in mind. I note that ASC has what they refer to as a Super Tower Trap effective to 30hz (whereas their 16 inch Super Tube Trap is listed at being effective to 45hz). These are 18' X 18" and can be ordered to any length. Nine foot long sections for the four corners of the room would retail for $1150 each, plus shipping. Would this be similar to what you had in mind? How would the effects of these compare to using a tri-corner trap top and botom with a mondo trap or something like that in between? Not that I am pinching pennys but the later would be less expensive.

bpape · « **Reply #15 on:** 14 Apr 2007, 04:30 pm »

The idea was that if you close the doors, you can basically treat it as the shorter dimension. You could easily put a false vent in the upper area between the doors and use a small computer fan or 2 to move the hot air out of the upper parts of the closet.

The solid triangular absorbers can be stacked to fill the entire corner area pretty much floor to ceiling and can be done for WAY less than $1150 - forget what a 9'x2'x2' box (just one) would cost to ship. In fact, you can do all 4 corners floor to ceiling for the cost of one of those.

In the upper corners, you may want to consider something like the 8th Nerve strips. We have a lot of customers who use a combination of ours for bass and reflection duties and the thinner treatments for general control of corner 'horn' effects.

In a home theater enviornment, the target decay times are much lower than they are for 2 channel so the amount of broadband absorbtion would need to be figured based on which way you want to lean - 2 channel or HT.

Bryan

PLMONROE · « **Reply #16 on:** 14 Apr 2007, 05:56 pm »

The room is now dedicated to 2 channel only. How tall are the triangular units? I presume they are they shipable by UPS, is that correct?

Paul

bpape · « **Reply #17 on:** 14 Apr 2007, 06:46 pm »

They're shippable and are just under 4' tall each. 2 to a box for shipping purposes.

Shoot me a PM and we can discuss offline.

Bryan

John Casler · « **Reply #18 on:** 14 Apr 2007, 11:02 pm »

Carpet Every Surface and use double layers of thick padding underneath aa

PLMONROE · « **Reply #19 on:** 15 Apr 2007, 03:26 am »

Yeah,right! I follow your advise on that one and my better

half will grab an ax and book a flight to LA!