I know this topic's been hashed out quite a bit, because I've been reading all o the threads containing "2235*" and "subwoofer". I took in those threads and did some modeling now that there's a PC in the house again. (Hey, it's at least competent for running Unibox, even if the Powerbook is better for everything else!) One alignment that seems almost too good to be true I'll call the GW alignment after Gordon Waters, who suggested it here.
According to Unibox, a single 2235H in a 160L vented enclosure tuned to 25Hz with a 15.24cm diameter (i.e. 6" round) and 42.9cm (about 1'7") port gives an F3 of 29.1Hz and an F10 of 21Hz (re: 80Hz, which is the Fc of my active crossover). Moreover, assuming no power compression - not an entirely invalid assumption, given that these subs are for a domestic system that won't often be often run at full tilt for long periods of time - they will give me 104dB at 20Hz and simply will not hit their mechanical limits until under 20Hz when fed 200W. (Obviously, a highpass at 20-25Hz would be required to protect the woofers.) Two of them should do 110dB at 20Hz, which as a practical matter means that they'll be loafing when playing real music.
Given the source I'd expect it's one of, if not THE, best alignments for the 2235H in a modestly powered (by modern standards, at least) home audio system. But surely I must have something wrong, because all that looks too good to be true. I double checked the T/S parameters I entered into the spreadsheet, and they're all exactly as on the JBL document. So what's going to turn this alignment into a pumpkin at midnight? I really don't care about port ripples at 380Hz....Unibox doesn't show me group delay, for instance...
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