Originally Posted by
RMC
Winspeakerz too asks a ton of dimensional info, you're not required to fill all of them, in fact the software asks for more than i have data to enter. When my patience is depleted i enter the important ones only, e.g. Mfr, model, impedance, power capacity, size, depth. The TS parameters represent pretty much what the software needs to give you a picture of driver performance, maybe not dispersion pattern. The TS should all be entered for better/detailed results.
D.B. Keele has shown, with his approx vented box method, that only three parameters are required to model a box (Fs, Qts and Vas) in order to get Vb, Fb and F3. Naturally, you don't get all the nice extras such as excursion curve, max power curve, etc. In the old days this pocket calculator method is what audiophiles used, including me.
With regards to box tuning, you decide which response curve you prefer. Would be interesting if you post it. Personally i model for flat response or so, and don't lose sleep for a one db ripple. Yes, i think you got the trick, normally one tries to go for flat response and wide bandwidth. There's always exceptions, for a dance club box tuning for a bass bump might appeal to some DJs, less EQ required.
Oversimplified, think of box volume as determining driver LF capability and box tuning as a refinement adjustment for flat, bumpy, etc. frequency response. That's about as basic as i can explain it. Your woofer is a 40hz one and since it has a Qts of .42 in principle would lead to a fourth-order C4 low-frequency alignment. Not a "strong" C4 (like Qts .5 or .6) because its at the beginning of the range, but such alignment usually has some response ripple and the box is tuned somewhat lower than driver Fs. Your Fb is lower than driver Fs. You seem to be on the right track. I can take my retirement now!
What you show on pic is definitely not bracing, rather glue blocks or cleats. These reinforce the cab joints only. They don't reinforce the box panels to prevent them from vibrating. With the power levels you have in mind its important. Plus that might mean some more box volume addition for space taken in the cab by bracing.
On the other hand, since you're after the fact here (boxes already made), one way to try to "save the furniture" is to use cross shape bracing (+), front to back and left to right panels, midway. Used alone its not ideal in the present case but will improve the matter up to a point. Trying to "salvage" the situation to avoid new boxes and minimize space taken in the box by bracing (e.g. using pieces of 2"X2" glued and screwed).
RE Could decoupling the cabs from the floor be part of the problem?
YES. Most speaker softwares assume 2 Pi box placement. That means DIRECTLY ON THE FLOOR (or in a large wall). The ISD response you see on computer screen is a 2 Pi response. When cabs are elevated off the floor, low frequency diffraction loss sets in, reducing the amount of LF. So another item to take care of...
Richard