Imaging and system stand placement


I have very holographic imaging in my system but others have told me on an online thread that having the equipment rack between the speakers (but behind the drivers) will never give you uncompromized imaging

my SRA Craz rack is very open

i would say that 90% of audio demos and more than 95 % of people's systems have the rack positioned between the speakers

i see these mega cost no object audio systems in professionally designed and custom built out rooms here at audiogon with the audio racks on the side walls and mono blocks up front. It must be a ton of cabling. I like keeping everything short and do not want to do balanced cables. And I would rather run speaker wire than interconnects long distances

would different length speaker cables work okay?

i feel if the backwall behind the listener, corners and first arrival positions are handled correctly then you will get appropriate handling of secondary room effects and resulting good imaging  - and this is more important than the rack position (if it is behind the drivers)

also the distance the speakers are from the wall behind and to the side of them is much more critical

i wouldn't consider putting a tv betweenin a main 2 channel room
or at least cover it

Thanks in advance for your comentary and experiences
 

128x128audiotomb
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 :-) 







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
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... 
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