Speaker placement

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60srok

Speaker placement
« on: 23 Oct 2005, 11:40 pm »
I have been experimenting with speaker placement. I used the Golden Ratio method to set up, the speakers were placed so the three nodes progress or differ from one another in Golden Ratio. This eliminates any unison or near unison resonance in the nodes.

http://www.cardas.com/content.php?area=insights&content_id=26&pagestring=Roo ...

Room is 13X15.5 speakers @short wall, ceiling sloped cathedral 8feet to 11 feet.
When I turned on the music I was astonished! The sound stage was huge, HUGE,i.e. my speakers were 3.59 feet from the sidewall and 5.81 feet from the rear wall. The sound stage was behind the speakers and was even bigger than the rectangle formed by the walls and speakers.

In fact I could hear the drummer on a raised platform and even tell his cymbal was higher than the snare!

Oh yeah, I was using B&W CDM2 and needless to say they disappeared completely.I am awaiting delivery of an ACI sub and was wondering what you all's experience with speaker placement was.

Needless to say this setup has 0 and I mean zero WAF. I tried slowly moving the speakers back but was almost immediately disappointed with the results. Since the sound stage was behind the speakers it became smaller almost instantly and I was spoiled!!

Any thoughts or suggestions?

thank you
Steve

LordCloud

Speaker placement
« Reply #1 on: 25 Oct 2005, 02:53 pm »
In my experience, in the two rooms that I've had my current speakers, I have always preferred near field listening, and by a very large margin. I listen currently somewhere in the neighborhood of 6 or 7 feet from my speakers and they are more closely spaced than what would be considered usual. The further I move the speakers back, the less involved I am in the music; images are less dimensional, the soundstage becomes more and more shallow, imaging becomes less realistic, I have to turn the volume up louder so the amp has to work harder and the sound suffers. For me, the closer you can get your speakers to the listening position the better. Some speakers sound better farther away, my speakers are time and phase correct and sitting farther from the speakers just seem to negate some of the benefits of the design. This is just my experience, yours will undoubtedly be different.

rbrb

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Speaker placement
« Reply #2 on: 25 Oct 2005, 03:16 pm »
Quote from: LordCloud
In my experience, in the two rooms that I've had my current speakers, I have always preferred near field listening, and by a very large margin. I listen currently somewhere in the neighborhood of 6 or 7 feet from my speakers and they are more closely spaced than what would be considered usual. The further I move the speakers back, the less involved I am in the music; images are less dimensional, the soundstage becomes more and more shallow, imaging becomes less realistic, I have to turn the volume up louder ...


I am in total agreement all though I sit 8' away from my speakers and they are 8' apart.  With proper room treatment and nearfield listening I hear more of the information directly from the speakers rather than reflected sound from room boundaries.

ScottMayo

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Re: Speaker placement
« Reply #3 on: 25 Oct 2005, 03:41 pm »
Quote from: 60srok
I have been experimenting with speaker placement. I used the Golden Ratio method to set up, the speakers were placed so the three nodes progress or differ from one another in Golden Ratio. This eliminates any unison or near unison resonance in the nodes.


In general there's more to room treatment than speaker position relative to the nearest walls, and you can probably improve imaging more by doing additional work. But speaker (and listener) position is hands down the best way to get an improvement. And it's a cool experience, the first time images snap into focus.  Groove to the effect. :D

Trapping the wall reflections entirely (well, nearly entirely) can get you even further. Do you have anything absorptive or diffusive at the reflection points? Keep experimening. :-)

LordCloud

Speaker placement
« Reply #4 on: 25 Oct 2005, 07:20 pm »
Quote from: rbrb
 With proper room treatment and nearfield listening I hear more of the information directly from the speakers rather than reflected sound from room boundaries.



I'm glad you mentioned room treatment. Many people think that near field listening negates the need for proper room treatment, or at least makes it less of a necessity. Nothing can be further from the truth. In my room, room treatment is king. As a matter of fact, I have found that speaker positioning and room acoustics are the two LARGEST determiners of the sound you will hear at the listening position, especially if you listen in the near field.

ctviggen

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Speaker placement
« Reply #5 on: 25 Oct 2005, 07:25 pm »
What do you guys mean by "near field"?  I had my system setup as near field (about 5-6 feet from speakers about 8 feet apart), but I actually like the system better with the speakers farther back (about 10-12 feet -- I'd have to measure).  My system is near the "1/3" rule -- speakers about 1/3 into room; I sit about 1/3 into the room.  I tried all types of placement and feel this is the best for this particular room.

LordCloud

Speaker placement
« Reply #6 on: 25 Oct 2005, 10:49 pm »
Quote from: ctviggen
What do you guys mean by "near field"?  I had my system setup as near field (about 5-6 feet from speakers about 8 feet apart), but I actually like the system better with the speakers farther back (about 10-12 feet -- I'd have to measure).  My system is near the "1/3" rule -- speakers about 1/3 into room; I sit about 1/3 into the room.  I tried all types of placement and feel this is the best for this particular room.


5-6 feet would definately qualify as near field, but it (like everything else) may not suit everyone's tastes. I prefer a near field set up, but no other audiophile I know of does. I have heard some far field set-ups sound pretty good, but they still don't really do it for me. But I'm sure anyone who's heard my system could say the same thing. It's all about flavor, and which one you like.

_scotty_

Speaker placement
« Reply #7 on: 26 Oct 2005, 03:55 am »
ctviggen, It should be noted here that "near field" is a flexible  term when applied to loudspeakers and varies with the design of the speaker.
Most speakers have a certain distance in front of them where the radiation from the drivers finally sums to a more or less "coherent" wavefront.  The peaks and nulls from the lobing errors are also closer together nearer the loudspeaker and one ear may be in a null while the other ear is in a peak which will sound like crap and also result in damn poor imaging. You can't listen to the speakers closer than this minimun distance what ever it is and expect good imaging and a flat response curve.  In your case 10 to 12 feet maybe "near field".  It should also be noted that the further away you are from the speakers in a room, the more comb-filtering effects from phase differences
between the direct and reflected sound will degrade any phase coherency that your speakers might have. At a minimum the effect will be to degrade any sense of vividness,immediacy and impact that the speaker might have compared to being right at the edge of where the soundfield first seems to gel and you cannot hear individual drivers playing.  
Scotty

ctviggen

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Speaker placement
« Reply #8 on: 26 Oct 2005, 10:49 am »
But if you have absorption at the first reflection points, how much comb filtering could there be?  I am 10 feet away from my speakers, 6 feet away from the rear wall.  The speakers are 5 (or 6 feet) from the front wall (the house is a raised ranch, so the wall is pushed out a foot about half way up the wall).  The speakers are about 30 inches from the sides of the wall.  I spent hours trying different configurations of room placement for speakers and person, including using ETF.  This is the best position in this room.  The room is 22Dx16wx7h, approximately.  

See also:

http://www.rpginc.com/news/library.htm

See fig. 10 of the PDF on the bottom.  This is about what my room looks like (measured using ETF where I currently sit), although I could use a little more absorption and definitely could use more diffusion.

ctviggen

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Speaker placement
« Reply #9 on: 26 Oct 2005, 01:08 pm »
Oh yeah, the speakers are RM40s and are toed in to cross at about the listener.  I have two Real Traps Mondo traps, one in each corner of the front room.  I have two HF Mini traps at the first side reflection points, placed there using the mirror method.  For critical listening, I place two Micro Traps between the speakers to reduce/eliminate reflections from my RPTV and the front wall.  I have two ASC subtraps/stands, which include bass trapping, positioned under each of my VMPS largers, which are along the wall behind the RM40s.  There is also a beam perpendicular to the front/rear walls.  This beam comes down about 1-1.5 feet (I'm not at home, so cannot measure it).  If I sit near field, reflections off the beam may be able to hit me.  If I sit far field, the reflections will reflect into the Microtraps.  I use a very thick rug on the floor between the RM40s and my listening position.

My room still needs more absorption (Real Traps and maybe some amount of 8th Nerve) for the ceiling and the beam and the front wall/corners.  It also needs more bass trapping (ASC tube traps in the corners of the rear wall and one in the middle of the rear wall) and diffusion (either ASC or RPG; the ASC tube traps include reflective surfaces) to create the time domain analysis shown in the figure of the PDF I referenced.  Nonetheless, I'm currently sitting the best spot as proven by many listening sessions and ETF analysis.  This spot may change as I change the acoustic properties of the room.  For now, though, it stays as is.

csero

Speaker placement
« Reply #10 on: 26 Oct 2005, 02:59 pm »
Quote from: ctviggen
See also:

http://www.rpginc.com/news/library.htm   ...



If you are on this page read this too:

The history of electronic architecture and variable acoustics.
http://www.rpginc.com/products/siap/siaphist.pdf

_scotty_

Speaker placement
« Reply #11 on: 26 Oct 2005, 04:01 pm »
Quote
The speakers are about 30 inches from the sides of the wall. I spent hours trying different configurations of room placement for speakers and person, including using ETF. This is the best position in this room. The room is 22Dx16wx7h, approximately.
 ctviggen, with this statement you have pretty much laid the ground work for answering your question.
Imagine your speakers outdoors with no walls near them and only the ground
as a source of reflected sound. This is a real world situation where comb-filtering is minimised. Response modification by comb-filtering and the randomization of phase coherency is an inevitable consequence of placing the speakers in a reverbrant room.  Room treatment can help how the speaker
measures and sounds under these conditions but in no way can the comb-filtering be eliminated with simple room treatments.  
Scotty

60srok

Wow!
« Reply #12 on: 27 Oct 2005, 10:15 pm »
Gentlemen,
Thanks so much for the nudges to near-field listening and room treatment.
I hung a blanket over the window to the right and the bookshelf to the left of the speakers. I also hung blankets in the corners behind the speakers and I can say ..wow and woowee.

The sound stage is large and almost as important the sweet spot is almost the whole width of the room @the-listening position. My speakers(B&W CDM1) are 6.5 feet apart and I listen @6 feet. We even notice music sounded better from the kitchen, which is a completely different room!

My wife is now exploring decorative window and wall treatments.

Thanks so much, this is awesome!!
Steve