Originally Posted by dschulz
Usually to achieve this sort of imaging, the two speakers need to be placed well into the listening room, rather than against the back wall.
I'm going to start by assuming what you call back wall (wall behind the speakers) is what I call front wall (wall in front of listeners). Moving speakers away from the front wall changes the ratio between the direct sound from the speakers and their reflections off the front wall. Since these reflections are coming from the same direction as the direct sound, then can muddy the front soundstage. IF you can't place the speakers away from the front wall, broadband absorption between them will do the same thing.
Toeing in the speakers also helps quite a bit.
Not all reflections are unwanted. Side wall reflections come from outside the L/R speakers, helping to widen the front soundstage and give a greater sense of spaciousness (their near-wall reflections are roughly where the Wides would go). You can control this effect with toe in: the more you toe in the speakers, the less their side wall reflections; the more you toe them out (e.g., pointing straight into the room), the more spacious the sound. Like having a slider that says Envelopment on one end and Detail on the other. Your preference will likely be somewhere in between.
So my question is this: have you seen anyone with a curved baffle wall, in order to get some toe in on the L/R pair?
One of our local home theatre group,
(Manoj), has a curved baffle wall. From what I remember, his L/R speakers are cross-toed (aimed at the listener at the opposite end of the couch) for some time/energy trading.
And with careful design and tuning can you achieve that same depth of soundstage with baffle-mounted or in-wall speakers when running in 2-channel stereo mode? Or is our inability to place the mains speakers 2 or 3 feet away from the wall an inherent compromise here?
You achieve the same results using any of the methods that minimize front wall reflections between the speakers: move them away from the front wall, cover the front wall with absorption, baffle mount the speakers.