Near field listening and speaker placement


We have a large music room (20x30) with a cathedral
ceiling and front outside wall angled out at 105 degrees,
(typical contemporary) with a tall bank of windows. In
order to avoid interaction with the glass, speakers must
be placed along short (20FT) axis of room. The room is
live (hardwood floors), although we have thick wool 9x12
rug in front of speakers

We would like to use a near field listening configuration,
and have several questions:

1. We assume nearfield listening is an attempt at zero
interaction with boundaries so that only direct path sound
arrives at the ear. Is this the consensus, or have we
overlooked something in the definition?

2. Speakers are placed 6 feet from the "back" wall. What
is the result of eliminating the back wall from the
listening equation?

3. In order to minimize interaction with the floor (the
closest boundary) should we worry about carpet on the
sides and behind, not just in front of our speakers?

4. Are there a canonical set of rules for spatial
optimization in near field set ups?

Guidance from the experienced is much appreciated.
hindemith
Hey check out the speaker placement guide on Cardas.com and more importantly for what your asking immedia.com. The immedia setup guide speciffically gives a guide on nearfield placement...
check out:

www.immediasound.com

in the Audio Physik section. AP specializes in nearfield listening.
Hello. I listen in near field. I have a very small listening room, 9' x 12'. I have a pair of Mirage MRM-1 Reference Monitors. I played with placement for weeks. What sounded best was the factory prescribed "rule of thirds." Listening position is 1/3 off the rear wall (into the room), speakers 1/3 off the front wall (rear and front refer to the 9' walls). This really cleaned up my room, eliminating most of the room anomalies. Only room treatments or room correction devices can really clean up the anomalies.

There is another school of thought. Speakers are placed in the middle of the room, with the listening position against the rear wall.

Near field = soundstage city.

1. That is my understanding as well. Be forwarned, near field is a bit like headphones, really big headphones.

2. My MRM-1's are rear ported, so they needed to be off the rear wall. Use rear wall distance to adjust your bass response, especially to get rid of mid bass boom.

3. I'm no expert, but I would assume more carpet = less reflective surface = quiter room. You've got the main area taken care of, though.

4. see above

I hope this helps. As previously stated, I'm no expert. This is just my own imperical data. Happy listening.

Erik
The Audio Physic website has excellent suggestions and rational on setting up loudspeakers in a room.

http://www.audiophysic.de/produkte/aufstellung/aufstellung_e2.html

Peace,
Ross
I think your questions are impossible to answer over the net. Like a Dr. ( I ain't no Dr.) trying to diagnose over the phone, But:

1) Yes that's the idea but there is always reflected sound. And you will not "aviod" interaction with the glass in a room that size no matter what the placement. You can reduce it.
2) See articles mentioned below
3) Will take experiments but probably yes.
4) Yes, See Cardas article below and Art Ludwig's site.

There are lots of theories on placement but all of the people I have talked to indicate that it is very room, taste, and system specific. Even with the best theory it takes a lot of moving stuff around.

You will definately have to work on the hardwood floor and glass with coverings if the entire floor is hardwood and the windows dominate a wall. I have heard some really nasty systems in this kind of room if not damped (Sorry). A very good short explanation of the classic "near field" set up by George Cardas is at www.audiolinks.nl/speakersetup/speakersetup.htm

A short piece by Joachim Gerhard (audio physics) is at www.speakerbuilding.com/content/1039. Gerhard suggests placement more toward the middle of the room than the classic placement that is described at the first site mentioned.

There is a wealth of information and recommended reading on this topic at Art Ludwig's site. www.silcom.com/~aludwig.

Good Luck

Sincerely, I remain