Ethan, you're right - it IS a very complex subject. There is no SINGLE right way to place speakers in a room, which is why I mentioned moving things longitudinally while LISTENING.
If you look at the various offerings in the realm of nearfield monitoring, you'll notice that some of the cabinets have radiused front baffles while others are square-cut - this affects the degree of diffraction around the corners of the speakers. Radiused edges diffuse the diffracted sound somewhat, but it's still there. When you place the speakers up against the front wall, this diffracted sound reaches your ears quicker and so will affect higher frequencies' phase relationship between direct and diffracted/reflected sound.
At the upper end of audibility, wavelengths are in the order of 1/2 inch, so you can see just how little difference in positioning it takes to cancel some highs while adding others (comb filtering)
The further you place speakers from the front wall, the less HF phase distortion, but at the same time longer wavelengths will suffer the same fate.
Then, we have the proximity effect - speakers too close to boundaries will give a bass boost (which USUALLY is not desirable, but in the case of small woofers sometimes works to advantage)
Add to that the fact that it's nearly impossible to design a 2-way speaker with larger than 6" woofer that doesn't have a "hole in the middle" , and we're left with yet another decision(s) - do we need a sub, do we need one or two, stereo or mono, where does it(they) go, where do they cross over, how to calibrate, ad nauseum...
Another typical problem is reflections from the front wall/rear of console, especially if it's a big console with a closed rear pedestal.
The only way I know of to get ALL these potential problems under control (except for maybe the sub question), is to heavily absorb the front wall, and if necessary the rear of the console area, and if using nearfields be VERY aware of early reflections.
These can come from the console surface (very common) from the shelf the speakers are sitting on (unless your shelf is set up so that the speaker sits at the very front, with the front edge angled the same as the speaker), from the sides of Video monitors, especially CRT's, from the ceiling, (usually NOT the floor) from the side walls (absorption at LEAST where these reflections occur) -
Basically, if you have a helper hold a mirror flat against any and all surfaces around you, anywhere you can sit at the mix position and see EITHER speaker in the mirror, that's where absorption should be placed.
All the comments above would apply to any rectangular room - if you're lucky enough to have dedicated space and want to do some building, you can build a "shell" around your mix area with side walls, front wall and false ceiling all angled so that ANY but direct sound gets re-directed AWAY from the mix position and to the rear wall, in which case see my EARLIER post regarding distance to rear wall... This type of construction is referred to as RFZ, or Reflection Free Zone, design.
As if all this weren't enough, lately I've seen reports of "The next big thing" (maybe), called ESS - stands for Early Sound Scattering, where all those hard front surfaces in a RFZ room are replaced with diffusors (prime #'s, quadratics mostly) - the claim is that mixes transport to different rooms much better, yada yada... So far, the only examples are in England and I'm NOT, so I can't comment on any of the claims yet.
Before I get to the decision point on my own new 2100 sf facility (16-foot + ceilings, I'm drooling already)(likely a couple of years) I hope to either travel to England (Lisa Stansfield's project studio, for one) or find someone in the US that's done it, so I'll know if it's something I want to opt for. At first glance, it seems like you could build reversible panels for those front areas with one side hard and the reverse being a diffusor. Hmmm...
Complex??? We don' NEED no steenking COMPLEX...:=) Steve
