Imaging and system stand placement

Audiotomb....

your friends concert - he might consider dry walling that area
and if he needs external soundproofing double it up with an air gap

He's now looking at a second layer of drywall with Green Glue between them on the wall - but the ceiling will require some "finess"

http://www.greengluecompany.com/
 
Cheers

Balanced low impedance signal lines can be run a long way without degradation, although I personally don't do long runs with my hifi…just live stuff. Differing  speaker wire lengths often aren't audible unless there are extreme differences, and even then hard to tell…I don't need room treatment beyond what is there naturally as my ceiling slopes up from the front wall 9 feet or so to a 15 foot back wall, with my listening couch 3 feet or so from the back. Speakers are in front and to the sides of a gas fireplace…plenty of gap and far enough in front so that the fireplace has zero effect on the sweet spot…rack to the side…enough furniture to keep the room great sounding in that spot anyway, elsewhere in the room you get standing waves, actual waves (damn water clean up), waves of nostalgia, waving tree branches…wait…those are outside... 

Willie

very interesting insight on the minnimal pull down effectiveness of the vinyl blind.  Move than likely you had standing waves building at the ceiling points or refracted off the back wall upward.

I have always had the idea of retiring in a mountain area with a sweeping view behind the sound system. perhaps support wall gaps right behind the speakers

your friends concert - he might consider dry walling that area
and if he needs external soundproofing double it up with an air gap

Audiotomb - I've just finished tweaking my room to the point where I am very happy with the result - plus the audio rack and a small cabinet and computer are still between the speakers - but behind the drivers.

Like you a dealt with the reflections from the wall behind the listening position which - which also had a 6ft x 4.5 ft bow window in the middle of it. The drapes in place were totally ineffective so I installed a 96" wide vinyl roller blind. This significantly improved clarity and gave the impression that the walls were no longer there. It also allowed the speakers to project the image further forward.

What surprised me was that I only needed to drop the blind by about 12" to get a dramatic improvement. Closing the blind completely offers very little in additional improvement.

I am fortunate in that on one of the long walls is a high back sofa and opposite that is a double doorway - so side wall reflections were mostly taken care of

Another area that improved things greatly was installing two 15" wide by 90" tall baffles behind the speakers which curbed an echo at that end of the room. I added lighting to the backside of the panels which serves as  mood lighting - the top half of the panel is translucent also so the light shows through

The biggest surprise was placing a trap on top of a 36" x 18" bookcase that is positioned in the right corner of the listening end of the room. The trap is simply a piece of 1" thick foam with a layer of mass loaded vinyl with slots cut into it. But I think you can actually get away with any heavy vinyl or rubber (like pond or swimming pool liner)
- the impact of this tweak was pretty mind blowing considering the small size of the trap involved

Armed with this info I then went to a friends condo that has 12 foot ceilings, concrete walls and is open plan.

Again we first dealt with the back wall and positioned a couple of traps at ceiling level. But  then we simply hung a 72" x 20" piece of vinyl from the ceiling such that it partially blocked the space above his kitchen cabinets - that one piece of vinyl was able to improve the clarity by simply blocking access to that part of the room which was plagued by echoes.

It would appear that vinyl is pretty good at deadening sound and it also vibrates, which transforms the sound waves into heat so there is little in the way of reflections.

The one observation that surprised me the most in both my room and my friends condo  was that the most successful of the treatments were those applied at the ceiling level and on top of my bookcase

I think the impact racks may have on the acoustic of a room may have everything to do with their construction and materials. My rack is simply steel legs with MDF shelves. My cabinet does vibrate, but also has a foam trap on the back of it to reduce reflections.

Food for thought :-) 

Don't want stand between speakers running 21ft cable from  preamp to amp.

Very nice observations

I don’t think it matters one bit to help imaging or necessary. Sure any placement changes can affect sound and imaging but that can be for good or bad, and depends on the room and what is already in it. It could make it better, it could make it worse, it could do nothing. Personally I think it’s best to absorb and break up those sound waves and not have them come back and muck up the direct sound from the speakers. Even without equipment there I think it needs some absorbing panels there on the back wall for the best sound. Some people even like to place a big sound absorbing panel right down the middle and said it really helps. Which I could totally see helping to keep the sound from bouncing a million times between the speakers and walls. I wouldn’t like the look though. I really like curtains over panels on the back wall to help absorb sound and reflections and look good and get that holographic sound and soundstage. Usually with the best sounding and imaging rooms and systems you’ll always at least see some bass traps in place of the missing gear. I believe isolating the sound of each speaker to each ear is best. Think of headphones, they have amazing world class imaging, and what is between them? Our big giant heads.

But with that said ’visually’ it does greatly improve the entire space and image soundstage in that it’s uncluttered and the affect it so much nicer to ’see’. Having a nice open area allows instruments, singers, and sounds to take their place on stage and travel visually unimpeded. There is something about having a big open space and sound floating there that allows it to vsually have a more 3D depth to it. Much like if there is a back wall very close it may still sound the same and image the same, but the wall can give it more of a flatter visual feel and you have to focus your attention more to grasp it. And I do think the best overall ultimate experience is to have the speakers far into the room and nothing between them. Nice and open. My favorite rooms are like that. And eventually what I will be doing. But right now even how my system is I’m getting holographic sound better than I’ve heard in bigger room and much better gear and more open rooms. But it’s still not quite the same experience or effect with gear and a big TV there and a back wall close. But dang it sure goes very deep and 3D.

And yeah I would never ever run interconnects long like that. I cringe when I see people do that. I’ve heard some pretty horrid sound degrading from long interconnects. It can become way to much resistance for that thin wire that is in them. Me personally when I go to a bigger room I’m going to have the back wall further back, then hide the TV behind a curtain, and have the other gear very low to the ground, so I can not have long interconnects and keep the speaker wire shorter too. But still keep the stage area very open.