Well, I'm about ready to start putting together my sound system in my truck, just gotta order my wire and waiting for some stuff to get in stock with Resonix and Parts Express. I do have a couple loose ends I'm trying to solve as I wait on the last of my purchases.
Mainly, I'm trying to decide how much sound deadening I should be doing in my truck, and have some questions about my subwoofer enclosure.
So I've been messing around with WinISD some more and gotten the hang of it mostly (had problems at first with putting in too many T/S specs and getting bad driver data at first).
I'm building a ported enclosure of some sort for my Alpine S-W10D4, and per previous recommendations was looking at putting it in a 1.2 net enclosure and tuning it low, around 32 Hz. The only thing that has hung me up some is the design of the enclosure.
Using a few calculators online, with my 550W amp and the size enclosure I'm using, I need at least 14in2 of port area minimum, with an optimal around 21 sq in, so larger than a 4" port. Even a 4" port needs about 25" of port length, plus space on the open end. I could build a long but shallow box to fit the 4" aero port, but using a proper sized port (4.25 ID for the 14 sq inches) starts making the box too long without at least one bend in the pipe (and the larger diameters with ports would also require a deeper box as well, throwing off the space provided). A 4" port would definitely be too small for this enclosure, correct?
Going with the idea the 4" port will be too small, this kind of has me thinking a round port would be out, which I thought eliminated me building the box myself. I haven't done a real woodworking project in years, so don't have a lot of confidence in building a slot ported box properly (or if I did, I'm not sure about my time invested vs cost to buy).
However, looking around I came across passive radiators (again, kinda new to the whole audio world) and started messing around with plotting those in WinISD. The biggest benefit would be that I could build the box myself no problem. Unfortunately, it seems like a large number of PR's are designed for enclosure/sub combos that don't match up with mine very well. I had some ok plots with two 10" passives, but there was a significant drop off compared to the sub in a ported box. The one I found that would work best is a PSI 15" Passive with ~400g of mass added to the cone, though I did have to adjust the box size to accommodate the PR and sub (15.5x15.5x13" interior measurements to fit the drivers on opposite sides of the box). Here's the plots I came up with:
Passive Radiator Enclosure (Red) vs Ported Enclosure (Green)
Given I am quite new at all of this, I can tell that the plots of course are mostly similar, with a bigger bump in the 30's with the PR. But I have very little experience determining what this actually means, and if it would be bad for my desired setup (mostly SQ). If it was a problem, would a DSP be able to adjust the signal enough to fix that?
Also, I haven't been able to figure out how to plot much beyond that graph and port velocity. Anything I should be concerned with like sub xmax with either box? Also, the Dayton DSP is out of stock until late July, and depending on my order from Resonix, I would have everything I need to install the project minus the DSP by the middle of next month. How essential would a subsonic filter be for either enclosure? (my mono amp doesn't have a HPF/subsonic crossover on it, didn't worry about it given the plan for a DSP) I'd plan to install it once I got it, but I'm excited to start getting my sound system installed already by just running high level signals to both amps, but don't want to mess something up by not having the subsonic filter.
And finally, speaking of sound deadening, I do have a question concerning my doors. I don't plan to leave the rear speakers in my 2017 F150 Supercab hooked up, but should I still plan on sound deadening the rear doors? They are quite small, so I wouldn't have too much to do, but is it worth is still? I'm thinking at least some dampening material on the outer and inner skins and CCF to decouple the door card, but not as extensive as my front doors. I am planning on some dampening material along the back wall as well, but don't really plan to get under the seats or on the roof at this time.
Sorry for the scattershot of ideas and questions, and thanks for all the help!