If you are suggesting a mirror image room, then no. There are three speakers up front aiming more directly to the rear, you are seated facing the front (and have directional hearing), and the rear speakers are more to the sides and pointing somewhat more inward. All of these factors, not to mention functionality and ergonomic issues, mean that things aren't going to be exactly mirrored. Yes, you have to take into account rear speakers when figuring out the treatments and geometry, and while a surround room should work for stereo, there is no guarantee that a stereo room will work well for surround. There are significant differences, though there are also significant similarities.
Rectangular rooms are pretty easy to predict, and with treatment, can work fine for stereo or surround. However, you don't need to avoid splaying altogether for a surround room. You do need to be careful about where you are sending reflections and what treatment they will encounter at the first reflection points of all 5 full-range speakers. If you ray trace the room, you can come up with a non-rectangular geometry that will work just fine.
For wall or soffit mounted speakers, if they are soffited up front, they should be soffited in back. If you can't use identical speakers, they should be timbre matched and substantially similar. This means you can get away with, for example, Quested 412s for L,R, and 212s for C, LS, and RS. They are the same drivers, same kind of box, and same electronics. The 212s just have 2 less woofers. You wouldn't use 212s up front with some bookshelf speakers in back, or Questeds in front and PMCs in back. However, realistically and practically speaking, though idetical is ideal, it is not imperative given reasonable planning.
As far as doors, windows, and glass or reflecive surfaces in general, you want symmetry, and you want to choose the placement and geometry carefully so that they don't cause reflection problems at the listening position. You also will take into account the reflective surface area vs. the absoption. You don't want a room completely covered by absorption, and given that you will have hard surfaces, you can place them such that they won't cause problems, and there's no reason that doors can't be some of those hard surfaces.
The last point to remember is that control rooms are places to get work done; they are not acoustics labratories. If you need a window to help your workflow, then put it in. You need to figure out how to impliment it to avoid problems, but the last thing you want to do is avoid things that will make your work better in a misguided quest for so-called "perfect" acoustics which simply don't exist, especially in small rooms.
Remember, the examples above are with music oriented rooms in mind. Re-recording stages and movie theaters are also surround environments, but with some different criteria, including greater room volume, surround arrays instead of direct radiators, and different absorption characteristics.
Brent Handy wrote on Thu, 04 January 2007 21:47 |
I am seeing many people not follow the surround monitor recommendations by the big boy wing. I was just wondering if the best option for a surround monitoring set up would not be a rectangular room, with consistant, broadband trapping throughout, as opposed to splayed walls and big glass windows/doors on the sides.
What's your thought on that? Should we not be reworking our rooms so that the surround speakers have the same "soffit" mounting as those in the front of the room (if they are)? Should we not move towards the same amount of bass trapping in the front as in the rear of the room, since many engineers mix full bandwidth material in all speakers?
What about the rooms with splayed walls with glass doors? It seems to me that some of the people that leave them open, would be doing more harm than good, trying to eliminate reflections, but changing the volume of the room.
Thoughts?
|