A 'slant' on Speaker positioning

Carlman · « **on:** 17 Sep 2003, 01:40 pm »

My digital camera is being borrowed so, I apologize for not having illustrative examples of what I'm about to describe.

I have a 14x17+ room. The '+' opens up into a kitchen/nook area. The couch forms a divide at about the 17' foot point.

So, I have something like this:

Code: [Select]


---------------------------------------------------------------------wall------------
|Chair|                                                                                    
          | Speaker L |                                          | Speaker R |    





                                   |coffeetable|

                        |||||||||||||Couch||||||||||||

Pretty standard... the speakers are towed in a bit... they have some room behind them and around them.... but, the sound is weak. The imaging is far from magical.... etc.

My wife decided she didn't like the room so, we re-arranged it the night before last. Now, everything is at a 45* angle from where it was. Except the chair that was next to the speaker is now to the left of the couch....

I re-measured things to get the speakers the same distance from the listening position. (I had done this in the previous setup)

Now the magic, emotion, or whatever is there. It could still use some treatment and some other tweaks but, my system is back. However, I'm essentially sitting in a diamond shape instead of a rectangle. The only negative is that the imaging/soundstage seems to rise to the right a bit. But, I'm not sure if that's due to the recording I was listening to last night or other things.

Has anyone else had this happen? Why is it so much better? The lack of reflections on the walls is my guess but, there's more to it.

Hantra · « **Reply #1 on:** 17 Sep 2003, 02:14 pm »

Hmm. . .The lack of reflections could be it. But I'll be honest with you. . . I have done the same thing before, and I only moved my speakers 1/16".

I think that even with this system of exact measurements, it's still all to easy to be off 1/4" or more. I have now two points that I measure from, and I can NEVER get both of them to line up right, even though they are equidistant from the side walls. So my walls are off. . No problem.

When I measure from the one point, and it shows right within 1/16", sometimes it really isn't right, and I can tell by just listening. The magic is GONE. Then when I measure from the other point, and find out I am 1/4" off or more, I start to wonder if I am THAT inadequate, or insane.

But when I line it up from the second point, it comes back.

And what you describe is what happened to me a week ago. I decide to move my Piegas to get a bit more bass. Holy cow that really screwed up EVERYTHING! The emotion vanished from the music. Sure, the bass was there. . . And sure, they were within 1/16". . Or so I thought. . .

Then I moved them back out where they were, and measured. . Still no emotion. Sucks. . . So I made a new midpoint closer to my chair. Voila. Even though the midpoints appear to be equidistant, they are not. This is very frustrating, so once you get it right, leave them alone! hehe

Actually, I am going to move mine again b/c I want a slight bit more width. That will begin the nightmare again.

It makes me wonder what kind of hell people live in where they have never done this measuring method, and never known what their system really can do. It's probably more difficult when you DO figure it out b/c once you hear that, you can't go back. They are likely better off not knowing. . hehe

Gosh I am in a rambling mood today!

Sorry. .

B

Carlman · « **Reply #2 on:** 17 Sep 2003, 02:21 pm »

I did spend a signifigant amount of time measuring after repositioning... more than the first time.... to the point my wife was really irritated with me. But, I was startled by the realism, 3-D holographic presentation of Dave Brubeck's 'Time Out' album. All the instruments were insanely real and well placed in a virtual room in front of me. A little harshness was gone and some mid-bass was warmer... just odd that the change made such a dramatic improvement.... and in a room shape that I would think would not sound as good as the normal rectangle arrangement.

Hantra · « **Reply #3 on:** 17 Sep 2003, 02:40 pm »

Quote

to the point my wife was really irritated with me.

Ahh the wives. . . It's amazing how they deal with this stuff. That's why I am glad I have my own little room. I just lock myself in and go insane with my tweaking. I'm glad I have wood blinds in there b/c my neighbors would see me walking around my room clapping, and think I worshipped satan.

Anyhow, I have read articles that recommend that type of corner placement as a way to eliminate reflections before they get to your ear.

B

8thnerve · « **Reply #4 on:** 17 Sep 2003, 02:54 pm »

Hantra,

It is VERY time consuming and infuriating at times. Imagine having to do it for all of your customers!

It is all worth it though when they lock in.

BikeWNC · « **Reply #5 on:** 17 Sep 2003, 03:20 pm »

I had used a diagonal corner placement for the past 6 months and have recently returned to a more standard speaker arrangement. I experienced very similar results as Carl, great depth of soundstage with a very emotional presentation. However, I also has some problems. In my room, the corner placement tended to emphasize the center image, narrowing the soundstage and bunching the image into what I would describe as a ball of sound. The addition of Eighth Nerve room treatments helped balance the image, but I felt that there was still some smear of the soundstage to the center. The addition of foam panels on the wall directly behind the speakers helped reduce the imaging problem, but I felt it could be better.

Andy

Carlman · « **Reply #6 on:** 17 Sep 2003, 04:12 pm »

I found that I went from so-so imaging to a wide and deep soundstage. I have a very hard time pinpointing where the speakers are now. I'm listening... and watching the speaker and hearing a piano that sounds behind it and higher...seemingly defying physics. The older position sounded like everything was coming from 2 speakers.

I think the ball is a good analogy but, maybe the size of the ball is different.... Or I'm in the ball vs. looking at it from the outside.

-C

TIC · « **Reply #7 on:** 17 Sep 2003, 08:12 pm »

Carl (and all),

Here is a link to a nice paper written by Steve Deckert of Decware (The Zen Amp Guys). He shows some nice examples of the change in reflecting points when you change from a rectangle to a diamond (angled) room.

BTW, he preferred the non-treated angled setup to a fully treated traditional rectangle.

http://www.decware.com/paper14.htm

BTW2, I have no relationship to Decware or Steve, but I have met him and have heard many of his products. When used it the intended setup, a Zen amp can sound GREAT for very little money. I don't own one, but have friend that use them in their reference systems......

Enjoy,

TIC

8thnerve · « **Reply #8 on:** 17 Sep 2003, 08:58 pm »

Quote from: TIC

http://www.decware.com/paper14.htm

I'm sorry, but does anyone REALLY think that sound bounces around like this!? We are talking about equalizing differences in air pressure, not photons with no mass and almost inifinite speed. I don't mean to start a war or anything, but it always sits wrong with me when people discuss sound like light. Just because they both can be represented by wavelengths doesn't make them in anyway similar. Those diagrams look like a pool table!

Also, no offense to Decware either, the information contained is very helpful, I just take issue with the diagrams and the previously mentioned concept.

Cheers all!

TIC · « **Reply #9 on:** 17 Sep 2003, 09:31 pm »

8N,

I'm only "the messenger"! I'm not endorsing Steve's findings and I have not tried it myself.

The sonic result does however seem to be similar to Carl's experience.

Quick Question: Does a nearfield setup of a 7' equilateral triangle reduce the need for room treatment? Just curious as this is my setup. What would be the first place to add treatment, corner, first reflecting point, behind speaker, etc? I know there are many factors, but just curious if there is an obvious starting point.

As Always, Enjoy,

TIC

8thnerve · « **Reply #10 on:** 17 Sep 2003, 09:39 pm »

Quote from: TIC

8N,

I'm only "the messenger"! I'm not endorsing Steve's findings and I have not tried it myself.

The sonic result does however seem to be similar to Carl's experience.

Quick Question: Does a nearfield setup of a 7' equilateral triangle reduce the need for room treatment? Just curious as this is my setup. What would be the first place to add treatment, corner, first reflecting point, behind speaker, etc? I know there are many factors, but just curious if there is an obvious starting point.

TIC

Just picking... Actually treatment is the same no matter where you place your speakers. I never treat a room differently due to different speaker placements. Treatment is based on the room itself. When I place product I do it to reduce the room's anomalies no matter where the sound is coming from. Speaker placement is crucial too, but it does not dictate room treatment. So the answer to your question is no. Most rooms require treatment to get the best sound. Different speaker setups will yield different results, but all of those result will be enhanced with treatment.

Hantra · « **Reply #11 on:** 17 Sep 2003, 09:49 pm »

I actually had the same reaction when I read this a while back. When I saw those room treatments, I was amazed that someone would do that. He added 2100 pounds of mass to the room!!!!! I'll bet Chuck Josephson has 68,000 pounds of mass in his room. . .

I just don't buy it. In my experience, adding mass has 90% of the time screwed up the sound. Unless of course you like dead, slow sound that's got some serious time issues.

Nothing against Steve. From what I hear, DecWare is great stuff. But at the same time, I totally agree that sound is not like that, and although it can be represented as such, that leaves a HUGE, HUGE part of the equation OUT.

B

nathanm · « **Reply #12 on:** 17 Sep 2003, 10:41 pm »

Most methods of trying to put sound into the visual medium are going to be tricky and inexact. I don't think the diagram is claiming that sound travels in distinct rays (unless they are using those new "Spam Your Local Grocery Getter At 500 Paces" devices they are developing) but it's quick 'n dirty enough to get the point across. Personally I find Steve's 3D graphical metaphors for soundstage to be quite interesting. (in a different article)

Is there a scientific way to plot\measure the actual air pressure radiation pattern in some form of 3D model or color-coded chart thingy? I know there's that laser infer-something or other, but I think that measures a surface not air itself. Hmmm...

Hantra · « **Reply #13 on:** 17 Sep 2003, 10:47 pm »

Quote

I know there's that laser infer-something or other, but I think that measures a surface not air itself. Hmmm...

Speaking of which. . . That laser inferometer is AWESOME! When I was out at Kimber, Ray showed us some things that thing can do. I was astonished to say the least. It will absolutely flip you out totally to see how much a speaker cabinet moves. That thing's a trip, and if they weren't a quarter million, I'd have to get one just to play with at the house. .

B

JLM · « **Reply #14 on:** 17 Sep 2003, 11:34 pm »

Seems like the more nearfield your speaker/listening arrangement, the less the room will be a factor at higher frequencies. This is easy to imagine as room size approaches infinity with a given arrangement. The same would apply to smaller arrangements in the given room size.

As the relative room size increases the delay between direct and reflected sound increases. The shewed speaker/listener arrangement mentioned on the Decware site does seem to help when I try it and, as you might think about it, would appear to help for the highest (most beamed, like light) frequencies. But I agree with Bill, most of the frequencies that a driver is designed to reproduce has enough dispersion to render a simple light beaming analogy useless.

As Bill said the effects of bass reinforcement and standing pressure waves from the room should not change as a result of arrangement.

Personally although I'm currently designing a sound room in my new house, my goal is to have it be "livable", with built-in book shelves/CD drawers, my desk/computer, and a few other furnishings. The room size shape will be optimized as well as many of it's features. But unless I can features can be reasonably incorporated into the room, they won't be included. So 2,000 pounds of diffusion/absorption panels, soundproof door/hatches, and ugly wall treatments are off the menu. That's one of the real pluses of the 8th nerve products. My design already has provisions for the 10 pack!

jeff

WilliamL · « **Reply #15 on:** 18 Sep 2003, 12:27 am »

BTW,

The "8th Nerve" moniker belongs to Nathan L., main designer and VP of Eighth Nerve--not me.

I keep getting PMs from people who think I am Nathan (8th Nerve) --the audio whiz kid. (I am not nearly as smart as him even though I am the Eighth Nerve President.

)

Thanks and all the Best,
Bill

Carlman · « **Reply #16 on:** 18 Sep 2003, 01:59 pm »

TIC,
Thanks for the site link and possible explanation for why things changed. I think the info there was good but, the diagrams may be taking it to a way over-simplified level. My house is the exact opposite of an anechoic chamber... it reflects EVERYthing. I can't hear my wife ask me a question without being within 10 feet because of all the reflection.... her voice gets really jarbled.

When Kris at 8th Nerve came to visit... and placed some of the pillows around, I could hear crystal clear what people were saying and could identify where they were. When I took them down after a month, that accuracy wasn't there, my imaging suffered, etc. Now I've moved into a new house with hardwood floors and some big openings that are really screwy. I need sound treatments in places far from the listening area just to keep the reflections from compressing into corners and then beaming back out and causing distorted sounds.

I don't know all the technical terms for what I'm talking about but, I know what I'm hearing. I think the angling I did helped keep the sound clear between me and the speakers better. Due in part by some of the statements in that link... However, I still need treatment... in a big way. It'll be another month before I'm ready to get started on it, though becuase it's going to be a big project.

TIC · « **Reply #17 on:** 18 Sep 2003, 03:46 pm »

Carl,

You are quite welcome! It may be an oversimplification, but Steve's listening results seem to be similar to yours,even if the diagram and explaination fly in the face of popular science.

Good luck on the new room! I'm building next year. I'm probably moving from my "cave" which is a small basement room used for my 2-channel system, my HT system, PC/office workcenter, etc. I'll be moving to a "cave in the sky" which will be a large bonus room over top of a 3 car garage. The house will be a Cape Cod with sloping ceiling and dormers in my "cave". It will likely sound VERY different than my current room.

Enjoy,

TIC

Psychicanimal · « **Reply #18 on:** 18 Sep 2003, 04:03 pm »

Quote from: 8thnerve

Treatment is based on the room itself. When I place product I do it to reduce the room's anomalies no matter where the sound is coming from.

Does this apply to diagonal setups, too?

http://www.decware.com/paper14.htm

8thnerve · « **Reply #19 on:** 18 Sep 2003, 09:13 pm »

Quote from: Psychicanimal

Quote from: 8thnerve
Treatment is based on the room itself. When I place product I do it to reduce the room's anomalies no matter where the sound is coming from.

Does this apply to diagonal setups, too?

http://www.decware.com/paper14.htm

ABSOLUTELY! We treat churches, schools, studios, listening rooms and home theaters, all based on the room not the sound source type or location.