I feel like the next step in my control room is diffusion. Bass is now really tight and punchy and from sweeping thru tones everything seems really even. There are no major dips or peaks. I haven't measured but I think it sounds like its within +-5db at worst. There's a tiny dip at 150 and a little bump at 78, but its very gradual.. like an eq with a low q. No tight weird dips or peaks.
Needless to say the room is VERY dry since about 25% of the cubic volume of the room is filled with deep broadband absorption and limp mass membranes covering sealed cavities. I made an educated guess that really worked with the membrane traps.. Tightened everything below 100 up a good bit.
I've been doing a lot of mixes in the room and low end is translating great. Its big and full with no mud, comparable to most major releases. The only problem I'm having is mixes are sounding harsh in the high mids. In my old room bass was always the problem. Now I'm mixing with too much attack and presence, which has to be a result of a dead room.
Will diffusion help bring a little more attack and top end clarity back in the room so I'm not mixing as aggressively? I can't imagine that a group of 10 2x2 omnifussors on the back wall will make that big of a difference in the mix position. Should I also add some in the front to add a little ambience to the room? Its incredibly DRY in there.