expanding the width of the sound stage

[WaynerN]

Mathew Polk of Polk Audio addressed this with his SDA speaker systems of the '90s. His method neutralized what is referred to a cross-talk distortion in which the left ear hears sounds from the right side, and vise-versa. The SDA speakers fed a signal to each other, creating out of phase signals with each speaker. This created a "boundary" and isolated the (for the most part) the left ear from the right speaker and the right ear from the left speaker (without creating a sound-stage hole between them).

As I suggested before, spreading the speakers out somewhat may create the same results to a lesser degree, mimicking the technique (albeit poorly). Obviously, the spacing between the speakers is critical to avoid a collapsed sound-stage, but spreading the speakers farther apart and increasing the toe-in angle may help.

A major contributor to a speaker's sound-stage is its higher frequency drivers quality of off-axis response. Some speakers may simply not have what it takes to create a wider sound-stage because of their driver's poor off-axis response.

 

[Superampman]

You don't need 8ft. from the side walls but you do need 4 min. for a sound stage with optimal potential, potential depending on the recording. So a decent sound stage needs a 16 X 16 room at the least. By that I mean to realize what the sound engineer intended. After that it will depend on your speakers. But for the most part placing them symmetrically in that space ideally 8ft. apart and 4ft. from the front wall and the same behind your listening position will yield the best possible scenario in this example. Now it's a matter of tuning them in with toe in. No matter what speakers I'm dealing with, optimal toe in angle is always the same. Some speakers are simply better than others but it seems optimization is a matter of geometry and nothing else, ime.

 

[JoeESP9]

The last thing you want is a square room.

 

[Superampman]

Agreed. I was referencing area. I have no experience with a square living room. Standing waves could be problematic I suppose.

 

[Dave_1962]

Here's what Cardas says about speaker placement

http://cardas.com/room_setup_main.php

 

[Gerres26]

Polk SDA's will give you what you're looking for.

This

 

[endsurg]

All great information. The problem I have is room geometry. The room is narrow and has a vaulted ceiling. There is a door way on each side of the room where the speakers have to be placed. There is only one feasible place for them and that is straight ahead and three feet apart. The only speakers I ever heard with an almost 180 soundstage where a pair of Dahlquist DQ-10's driven by a pair of Marantz 9 monoblocks set up by Saul himself. I was thinking , in addition to room treatment, I could put a pair of really good blue tooth speakers on the right and left walls. It will take a lot of manipulation but I'm hopeful.

 

[JoeESP9]

Isn't really good Bluetooth speakers an oxymoron?

 

[Northwinds]

For me I notice a difference with different amplifiers. The widest most 3D sound is from my Marantz 1060 and 2220 that were restored with very nice parts including films and 4-pole main filter caps.
The Rogue Sphinx (I never saw or heard one) from what I read should be a very able amp...so I would try speaker placement.
My room has two corners cut at 45°, length of that 45° cut about 2 meters. My speakers are about 2.5 meters apart and placed by that 45° portion but still not parallel to that wall. My soudstage is very nice and airy and 3D.
I once tried putting the system on the other side of the room, parallel to the wall, with a big window on one side. It was awful, I had lost all stereo imaging.
I hope this makes sense, a drawing would be a much clearer explanation

An amp has nothing to do with soundstage, that is your preamp and speakers. An amp only amplifies what is fed into it. I agree some amps have a fuller sound but regarding soundstage, no. Again, preamp choice and speaker placement are the main factors of soundstage