Both their sealed and ported recommendations sound great for SQ, it will degrade slightly with ported, but not by much IMO. Download the PDFs on that sub and JL will give specific dimensions for the box you choose. Either will work well.
It's a little peaky, but that's what most people like. It's well rounded in a vehicle, actually, saying most vehicles tend to have max gain in the 50s and slope off above and below that, it rounds out. WinISD can be inaccurate at times, too. For a more purist alignment, you'd probably do a little better with something like 2 cu ft net tuned to 26-28. I've heard them with that box, though, and they're really well rounded. The peaky response is mainly to blame on the sub, it's designed mainly for small sealed, EBP is kinda low. JLs in general tend to be that way, but it's not a horrible thing, they still work well in ported applications.
WinISD can be pretty inaccurate at times, especially with certain subs, and it's very hard to predict cabin gain well. Depends on too many things to accurately portray in vehicle response as simply different sub locations, boxes, sound deadening, etc. will all have an effect on cabin gain. If I use WinISD, I do so while still considering what I know usually works well.
lol, you should see what they look like in a 2.86 ft^3 box tuned to 24.5 Hz(winISD's recommendation). A beatififul curve flat all the way to 20 Hz(I'm done uploadin em tho, what a pain, hehe).
I foolishly built that one. Sounds fantastic at low volume(blows your hair real good), but you can't turn it up much and it doesn't handle transients very well. At least it would be a near perfect fit for a pair of Shivas.
How would a pair of those guys sound @ 250 watts ea? nah, nevermind that box kills my cargo space almost completely.
hmm.. Shivas in 1.75 ft^3 sealed would only be a bit bigger than my 10w3 box. I could afford a pair of those and that would be a significant SQ improvement over the 10w3's wouldn't it?
I dunno I guess I feel like I'm wasting 500 watts by not driving a 1 ohm load with my Xtant 1001dx but if my front components are getting overpowered as it is I guess I really don't need the full 1000 watts.
Hmmm... wonder what 4 isobaric Shivas would sound like in .9 ft^3 sealed per side. I could use 1000 watts then! lol, but thats $500.
Oh, I installed my little PQM1 one band parametric EQ module in that amp. Can you make up some of the low end(not ultra low) response deficiencies of sealed enclosures with one of them things?
I tried messin with it with my 10w3's ported @ 28.8 Hz. I set the center frequency at 20 Hz(lowest) and the Q at the lowest(1.0). Just a lil bit of boost added a whole poopload of bass, but I was worried about overpowering my subsonic filter(set at 20 Hz) so I have the boost up just a tad.
I was wondering if boosting frequencies a sealed enclosure normally wouldn't really like to play requires a whole lot of extra power or not.
I looked at that diagram fishy and the response seems to drop off tremendously at lower frequencies. Was that a model for 10w3's or my 12w6v2's? I got confused reading your guys' responses cause I wasnt sure who's sub you were referring to. Im feeling a smaller enclosure might work better for my needs. 1 cuft is within range for the 12w6v2, how would that work out for me?
My 10w3's are actually playing "lower" on those plots but their in JL's SQ or what they call their "purist" enclosure. Those plots are a lil decepetive tho. They're representative(I believe) of how they would sound in an anechoic chamber(no reflections) and don't include cabin gain. WinIsd is used primarily to model home applictaions where "room" gain starts out at much lower frequencies. Those subs will play a lot lower in an actual vehicle.
It bothers me too. Sealed booxes generally look like they'd have incredibly weak low end response on these plots but apparently in a vehicle they don't.
I've lost all confidence in my ability to design a suitable enclosure using this stuff so I'd either E-mail JL Audio for alternate enclosure suggestions(ask for normal, purist, and dB monster, hehe, thats how they used to rate em anyways) or just use what they recommend here.
Personally, David, I'd do around 1.25 like specs recommend, maybe a even larger. The problem w/ smaller boxes is degraded transient response and decreased bandwidth, plus more power needed to get the sub to full excursion. I'd go between 1.25-1.75 net, personally, or 1.25 and stuff with polyfill.