[Christof]

I just finished a new pair of 4-ways and would like to now ask for a little help in understanding my room dynamics before I try to add any treatments.  I figure this is the place to ask.

My listening room is 12 ft wide, 8ft tall and 38 ft deep.  There are 3 adjoining rooms each with a 3ft wide cased arch opening leading into my listening room.  They are all along one side of the room, located on the 38' wall.  Because there are no doors this makes the total area (of actual air space) approx 700sq.ft.  However, my listening room is only 450 sq.ft.    The speakers/subs are placed along the 12' wall and I sit about 10' back from them.  Thus my listening position is just about 1/3 of the total depth of the room.  The back of the speakers are placed 18" from the wall and 30" from the side walls with a 7' projection screen hanging between them.  I hope I'm painting an OK picture for you folks   The 38' walls each have a 4' high knee wall with a pillar extending up to the ceiling.  The knee walls only extend 3' into the room and are located 12' from front wall (exactly where my listening position is).

I have dual 12" Peerless XLS subs w/ f3 @ 27hz http://www.selahaudio.com/id13.html.  I listen to everything from Bluegrass to Primus depending on my mood, usually at pretty high volume levels...I love to get hit in the chest by the kick-drum.  The room is all Hardwood floors, 75% covered by large Oriental rugs. No exposed hardwood b/t listening position and speakers.

Given all this info can anyone fill me in as to the dynamics of my listening area?

Thanks for any input you guys can give.
Christof

[JLM]

So what you mean by "fill me in as to the dynamics of my listening area"?

How does it sound to you?  What are your complaints?  Without this sort of information obvious suggestions is all the help you can expect:

Bring the speakers farther out from the front wall.

Install side wall reflections at "first reflection" points between speakers and listener locations.

Install an acoustical drop ceiling to absorb first reflections and get away from the 1.5 multiple between height and width of the room.

Install a back wall to create room about 19.5 feet long.  With this you'd have room height/width/length ratios in a classic 1 x 1.618 x 2.618 proportion to minimize reinforcement of standing waves.

Wire audiophile grade A/V dedicated electrical receptacles on their own circuit.

Replace metal ductwork with lined fiberglass.

Add an insulated exterior door with weatherseal to minimize furnace and other outside noise.

Several technics are available to insulate walls from outside noise (and vica versa).

[Christof]

JLM

The room sounds 'boomy' to me.  It sounds like there is some kind of amplification of a paticular bass freq. I guess I should buy a test tone CD so I know eqactly what it is.  I do have a dedicated circuit for AV, a 20amp curcuit on opposite bus bar from appliances with star wiring to all outlets (isolated ground) involved.  From there I have variations of the VH DIY Flavor cords going to all components.

What I was really meaning to ask was 'a room of this area and geometry will have a tendency to be________?'   This is a very general question, I realize, but I'm new to this.   My complaint is that the room sounds like a subway tunnel, sans echo.  I'm curious if this is because of my room or my system.  Will an untreated listening room of given dimensions always exhibit certain sonic characteristics?

thanks
c.

[zybar]

JLM

The room sounds 'boomy' to me.  It sounds like there is some kind of amplification of a paticular bass freq. I guess I should buy a test tone CD so I know eqactly what it is.  I do have a dedicated circuit for AV, a 20amp curcuit on opposite bus bar from appliances with star wiring to all outlets (isolated ground) involved.  From there I have variations of the VH DIY Flavor cords going to all components.

What I was really meaning to ask was 'a room of this area and geometry will have a tendency to ...

Chris,

I would go read some of the articles over on Ethan's site (www.realtraps.com) and some of the white papers on the Harmon site:

Louspeaker and sub placement:

http://www.harman.com/wp/pdf/Loudspeakers%20and%20Rooms%20-%20Working%20Toge ...

http://www.harman.com/wp/index.jsp?articleId=122

http://www.harman.com/wp/index.jsp?articleId=1003

Room Node Calculator:

http://www.harman.com/wp/index.jsp?articleId=131

At the end of the day, I firmly believe you need products like Ethan's minitraps + proper placement + room/driver correction to achieve maximum results.  

Best of luck and I hope this helps a bit.

George