Hi,
I've spend a fair bit of time looking into the same thing over the past few weeks and it takes a bit of working through. About the only thing that I've seen any sort of consistent answers on is what a
bad room looks like - which is an unfurnished cube shape, where all three dimensions are the same and where everything rattles, bounces, reflects and echoes like crazy. After that it seems to be a case of "How complex would you like to get?"
Roughly speaking it seems that a 'good' room is longer than it's wide and has a combination of bass traps and various types of absorbing and diffusing panels to tame the sound at critical points. The plans I've seen suggest that ideally you set up in the middle of one of the shorter walls (preferably a bit away from the actual wall) so that the sound heads down the longer direction. Probably plus some more thing I don't understand yet...
The problem is that we have to deal with a big range of frequencies in music. From rumbling bass notes that get close to the bottom end of our hearing spectrum through to very high pitched stuff. They all have different characteristics though. Bass can cut through quite thick walls and travel long distances, and the mids and highs all have their own peculiarities too. So in any sort of room some frequencies will be absorbed and 'deadened' while others will be reflected and will seem more prominent. And as this process happens they all start interacting with each other as they bounce around, bump into each other and decay (or something like that!!). So at any given time in a room you have a complex mixture of what is happening now, what happened recently, and a changing blend of sounds all meeting up and shoving each other around....
All that is inevitable, in any room. So the trick is to try and tame the more extreme stuff and get to know what that particular room is doing to your sound. For instance, if I run a test file in my current room it sounds as if the volume knob is being cranked up and down at certain frequencies. I don't notice that much when playing regular music, but by playing frequencies one at a time I can hear just how out of whack it actually is. Just out of interest I set the gear up in a big open space outside, and the difference was really obvious - the test file volume was then absolutely even, but of course it all then sounded a bit 'flat'. Our ears tend to like a room that's a bit 'lively' and feel a bit uncomfortable if it's too acoustically dead.
It depends what you want to use the room for too. I don't care much about the room as a whole but I do want to get a good reliable flat response at the spot where I'll be sitting to mix tracks. Otherwise my mix might sound fine in that room but not good somewhere else. You might think that if you set up a decent set of monitors and pointed them straight at your head, in a reasonably small triangle, that you'd get a pretty good result. Unfortunately, the room has a far bigger effect than we might hope. So it's good to at least find out how big the lies are!
Most of the general ideas aren't too hard to grasp (if you can decode the 'audio -speak' that the experts talk) and making some improvements is probably also fairly achievable. But doing really accurate and detailed tests can get very complicated. Good luck with your own experimenting.
Chris
