Originally Posted by jkasanic
If we've reached some sort of consensus here then I'd appreciate it if you could continue this discussion in more detail?
(e.g. addressing absorption
for bass decay
and modal ringing, broadband absorption for high gain early reflections and then onto the more difficult part of determining which treatments are necessary to achieve this as well as the prescribed ISD Termination and likely need for a kicker). What I've seen so far is that it's easy to say these first items need to be addressed but an altogether different matter on the best approach (besides trial and error) to achieve the criteria as what you do early in the process could have repercussions later on (i.e. overdampening).
Once you know the criteria, and the most critical features of it, then we can look at how to go about things.
IMO, in small rooms, I am of the philosophy that you cant ever have too much bass trapping. I have yet to see an example of where too much has been used to a detrimental effect, whereas the lack of it or insufficient amount of it is quite common. Anywhere corners meet is a potentially good place. Particularly where three corners meet.
In small rooms, high gain early reflections need absorbing. Redirection is a good option IF your willing to splay your walls (something most people dont want to do). And diffusion I am not a fan of for high gain early reflections, but it definitely has its place for later lower level ones.
Now the rest of it is particular to each room. What you have to ask yourself at every wall surface is whether:
(Our three most common tools)
...is going to best preserve or compromise your isd gap. An untreated wall can be taken as redirection, so look where each untreated wall surface is redirecting the energy from each speaker and see if it intrudes on the isd gap. See if its far enough away where diffuse energy will arrives late enough. Or reflect it in a more beneficial direction. By looking at all your walls in this manner, what treatment is necessary become self apparent.
Along with this, you have to decide how your going to terminate, and how to get the path length long enough. If your fortunate enough to have the walls behind the listening area 11' or 12' distant, then things are much easier since a single bounce from them will arrive back at the listening area after 20ms. In this case, diffusion would be a prime candidate. If your not fortunate, and your back wall is less than 11', certainly if its less than 9 ' or 10', your left with a dilemma. Your either going to have to have a isd gap less than 20ms or your going to have to bounce the energy around at least twice. I cant say for sure which is the better or more feasible choice for all rooms. This must be addressed on a case by case basis.