@darrenmc posted something very specific:
"I am looking for a greater soundstage and bottom end slam while maintaining the clarity of the PMC’s."
Within the context of his 15 x 12 foot room, I’d like to explore what might result in a "greater soundstage" (while "maintaining the clarity of the PMC’s").
In my opinion, early reflections are a primary issue in relatively small rooms. The detrimental effects of early reflections are under-appreciated because they aren’t something we are even aware of, and when we hear their effects, it’s not obvious that’s what we’re hearing.
Early reflections tend to degrade clarity. Recording studios go to great lengths to minimize detrimental early reflections, while still preserving as many beneficial later reflections as they reasonably can.
Early reflections also degrade soundstage depth. They super-impose a characteristic "small room signature" on top of the soundstage on the recording. This is another reason why recording studios manage reflections as described above: They don’t want the control room super-imposing a "small room signature" on top of the natural ambience they just captured in the live room.
We can’t afford to build our home listening rooms to studio standards, but we can use speakers that don’t work against us in a small room. The secret is, the radiation pattern.
Briefly, we want a radiation pattern that effectively minimizes early reflections off of the side walls, and it would be nice if we can minimize the floor and ceiling bounces as well.
So imagine we have speakers with a radiation pattern that is only about 90 degrees wide (-6 dB at 45 degrees to either side of the main axis), and we toe these speakers in by 45 degrees. Now neither speaker generates a significant reflection off of the near side wall. The first sidewall reflections of the left speaker is the long, across-the-room bounce off of the right-hand side wall. And vice-versa. This significantly reduces the amount of energy in those undesirable early reflections and helps set the stage for improved soundstaging.
Now one of the things that makes a good big room sound so nice is, a greater proportion of the reflections are fairly late-arriving and therefore beneficial (assuming they’re spectrally correct or close to it). The ear/brain system judges the size of a room by the time delay between the first-arrival sound and the "center of gravity" of the reflections. We can trick the ear/brain system into thinking the room is bigger than it actually is by adding a bit more late-onset reverberant energy. This results in less "small room signature" being super-imposed on the recording, so we hear more of the recording’s soundstage and less of the room.
I realize much of this is counter-intuitive; the standard recommendation is small speakers for a small room. But few small speakers have the sort of pattern control that addresses the problem of too many early reflections, which becomes correspondingly worse as room size decreases.
Not that this is the only thing that matters, but if one is serious about creating a realistic illusion in a small room, ime the radiation pattern matters a lot.
Duke
dealer/manufacturer
