[SteveFord]

I've been doing the stupidest thing for months:
I got it into my head that because the 20.7s are physically larger than the 3.7s they would have to be pulled out further into the room.
I was worried that the bass would be too overbearing and boomy.
This morning I put them in the exact same spot that the 3.7s occupied and guess what? 
Success!

I ended up with them 55" out from the front wall which is the magic spot here.

How far out is everyone else running theirs?

[kevin360]

I don't have 20.7s, but it would be really far out if I did!

My 3.7s are a little over 9' out, but they are in a big room (that's close to a third of the room length (~34')).

[SteveFord]

Could I borrow your room, please?
I promise not to make a mess.

[medium jim]

I made a similar mistake with my 2.5's which are close to the same size as 3.7's, when I put a different amp into the system.  I moved them thinking I was doing the right thing and ended up in the almost exact same spots.   I have them 38" off of the front wall and 36" off of the side walls in a room that 16x15x8.5'.  My head is about 3' off of the back wall. 

Jim

[kevin360]

Could I borrow your room, please?
I promise not to make a mess.

Sure, and you can make all the mess you want - as long as you bring the 20.7s.

[SteveFord]

Oh, I was picturing the room coming to me.
I'll have to do some recalculating.

[Maritan]

I have an irregularly shaped room, but essentially I have the 1.7s out about 4' from the front wall. Sounds pretty good with a wide sound stage, but still working on getting some depth from the soundstage.

Once the amp is ready to go again, that is.

[medium jim]

Oh, I was picturing the room coming to me.
I'll have to do some recalculating.

I'm not sure if they have them everywhere, but in my neck of the world, we have Band Practice lockout rooms and they're big enough for a full on big rig stereo....they cost about 400.00 a month to rent....get some friends together and use it as a hangout and to try different gear.   

Jim

[medium jim]

I have an irregularly shaped room, but essentially I have the 1.7s out about 4' from the front wall. Sounds pretty good with a wide sound stage, but still working on getting some depth from the soundstage.

Once the amp is ready to go again, that is.

The depth comes from a couple of sources. 

The first is how far apart you have them and the amount of toe in....the wider you can get them and still have the middle imaging the better.

The second is your relative head/ear height with optimum where your ears are slightly above mid-panel. 

Wait, there is a third factor, Tubes....Tube amplification/preamplification will create a huge (wide/deep) and holographic soundstage. 

Jim

[kevin360]

Oh, I was picturing the room coming to me.
I'll have to do some recalculating.

Alright, if that's what you want, but you're paying the shipping both ways.

[satie]

I've been doing the stupidest thing for months:
I got it into my head that because the 20.7s are physically larger than the 3.7s they would have to be pulled out further into the room.
I was worried that the bass would be too overbearing and boomy.
This morning I put them in the exact same spot that the 3.7s occupied and guess what? 
Success!

I ended up with them 55" out from the front wall which is the magic spot here.

How far out is everyone else running theirs?

How about a Limage/HK positioning with the speakers by the sidewalls without toe in, pulled 13 feet into your 30 ft long room, you sit a few feet from the back wall? In my experiments I pulled it off for the front and middle of the orchestra but not for the back of the orchestra, which is improved but still has the "normal" presentation. The imaging is staggeringly real with full sized instruments in a space far greater than your room. Apparently my room is a tad too square to do full justice for this setup on the wide wall, but yours is nicely rectangular and should accommodate it.

http://www.1pekingroad.com/zaspx/replies.aspx?topicsno=7&subjectno=874&uppersubjectno=874

[Letitroll98]

I've been doing the stupidest thing for months:
I got it into my head that because the 20.7s are physically larger than the 3.7s they would have to be pulled out further into the room.
I was worried that the bass would be too overbearing and boomy.
This morning I put them in the exact same spot that the 3.7s occupied and guess what? 
Success!

I ended up with them 55" out from the front wall which is the magic spot here.

How far out is everyone else running theirs?

It's because you have 8' ceilings.  Try 59.28" out.  It doesn't matter if you have MMG's or 20.7's, if you have dipoles and 8' ceilings, the placement is 59.28" out.

How about a Limage/HK positioning with the speakers by the sidewalls without toe in, pulled 13 feet into your 30 ft long room, you sit a few feet from the back wall? In my experiments I pulled it off for the front and middle of the orchestra but not for the back of the orchestra, which is improved but still has the "normal" presentation. The imaging is staggeringly real with full sized instruments in a space far greater than your room. Apparently my room is a tad too square to do full justice for this setup on the wide wall, but yours is nicely rectangular and should accommodate it.

http://www.1pekingroad.com/zaspx/replies.aspx?topicsno=7&subjectno=874&uppersubjectno=874

Are you getting a U shaped soundstage with the HK?  I loved the presentation, but couldn't solve or live with the outside of the image wrapping around to the speakers.

[josh358]

I have an irregularly shaped room, but essentially I have the 1.7s out about 4' from the front wall. Sounds pretty good with a wide sound stage, but still working on getting some depth from the soundstage.

Once the amp is ready to go again, that is.

I've found that depth is proportional to distance from the rear wall. The reason for this is simple -- we judge the size of an acoustic space by the timing of the reflections: if they follow the direct sound quickly, we assume that the wall is close, and vice-versa. So I'd consider pulling the speakers further out. Another thing that can help is diffusion at the first reflection points on the front wall (the place where you would see the speaker reflected in a mirror from your listening seat). This reduces the amplitude of the first reflection off the wall and makes the room acoustically larger. I've found that the shape of the wall is important. It should be essentially flat (a bit of roughness is good for diffusion). Finally, as Jim points out, some electronics do depth better than others.

[medium jim]

I've found that depth is proportional to distance from the rear wall. The reason for this is simple -- we judge the size of an acoustic space by the timing of the reflections: if they follow the direct sound quickly, we assume that the wall is close, and vice-versa. So I'd consider pulling the speakers further out. Another thing that can help is diffusion at the first reflection points on the front wall (the place where you would see the speaker reflected in a mirror from your listening seat). This reduces the amplitude of the first reflection off the wall and makes the room acoustically larger. I've found that the shape of the wall is important. It should be essentially flat (a bit of roughness is good for diffusion). Finally, as Jim points out, some electronics do depth better than others.

You are right, I have to use diffusion in the middle of the front wall and absorption as well behind the panels, this seems to work best for my room as it makes the room acoustically narrower and yet sound bigger.

Jim

[josh358]

You are right, I have to use diffusion in the middle of the front wall and absorption as well behind the panels, this seems to work best for my room as it makes the room acoustically narrower and yet sound bigger.

Jim

I wonder what the absorption does?

I've also found that sound tends to wrap around at corners. (I've found in general that the sense of depth tends to follow the wall, like a sonar image -- though somewhat behind it, my ears seem to compromise between the reverb on the recording and the reverb in the room.) Facets are one possible solution, diffusion of the corner reflections another.

Another thing that I've found can make a difference in imaging is tilt.

[SteveFord]

Letitroll,
I just dragged out the tape measure and from the wall they are at 59 and a smidge, I was measuring from open vertical blinds.

Wherever you got your calculations from sounds right to me.

[shadowlight]

Letitroll,

Where did you get the measurement information from?  Could use some help in optimizing the sound stage by placing the speakers correctly.

To OP apology for threadjack.

[medium jim]

Josh:

It eliminates the reverb effect by smoothing out the front to sidewall reflections.

Jim

[Pryso]

"I ended up with them 55" out from the front wall which is the magic spot here."

Steve, I was going to ask if you had tried them at 60" but your updated measurement answered that.

As I posted previously, and josh has mentioned several times, 5' is an optimal minimum distance from the front wall for dipole speakers.  I assume that applies to SMGs, 20.7, and everything in between.  When lesser distances are utilized then diffraction at the reflection point can be a substitute.

[satie]

Are you getting a U shaped soundstage with the HK?  I loved the presentation, but couldn't solve or live with the outside of the image wrapping around to the speakers.

No, I did not have that issue, I did get a hole in the middle where the early reflections from the equipment rack were an issue (also for the Rooze arrangement) and that was solved with a pair of absorptive "walls" (chenile and velveteen throws on styroboard) jutting a couple of feet in front of the rack that prevent the back output of the speakers from reaching the rack. With that in place the arrangement filled in the middle and worked its magic on front of the orchestra all the way back to the woodwinds. But the rest of the back of the orchestra did not get stretched out the same way and remained as it was with the conventional placement.

The thing I need to do to get this working is move the entire setup to the short wall  - but that means moving all the furniture amps and excess turntables - which is not going to happen with my smashed back. But I might be able to finagle it into working right on the wide wall with a split arrangement of the bass panels from the mid/tweet - more experimentation to come when circumstances allow.

I am going to throw a WAG that you had that U shaped soundstage because of a similar object in the middle jutting forward - rack or TV or screen.