Off the bat, I believe from what I gather via the T/S specs on these, that they may not be the best drivers to utilize a 4th order bandpass enclosure for, however, I'd certainly like to try
I've had amazing luck with these drivers, being able to break a '50dB on a pair of these 12" drivers on less than 2kW clamped on a 42Hz tone in my trunk car that has a solid rear seat, that of which does not fold down of course, nor even a ski hole for any access to the trunk
. A good bit more achieved just under 3.2kW clamped (150.8dB - uber clip? Hehe), and the ability to even play music at '50dB on some dynamic power that should be right around or some under the 3kW mark I'd assume. I'll be testing it all soon before I do an entire rebuild.
And the greatest thing of it all? These things just keep getting louder and louder with the less volume I use! Lol, and the passband/frequency response doesn't suffer too badly while at it either. Heck, with each driver only seeing 1.37ish cubes net (F3 is 33Hz) in a shared chamber enclosure and a homemade 8" aeroport (woofers up, port to the driver's side) I stay within 1dB across an impressive frequency range for SUCH SMALL volume per driver, it performs as a decent musical enclosure tbh. That is right around fart box volume for single 12" drivers no? Err, maybe not, rather a little less like maybe 1 cube net with uber port area? I only compete with frequencies usually ~<45Hz, I know nothing of high Fo full-on SPL enclosures.
Anyhow, of course with larger enclosures I made before for these drivers, such as 1.5, 1.75, 2, and even 2.5 cubes net per driver in a shared chamber and same tuning (F3 of 33Hz) as well as the same ratio of port area differing only a tad whether aeroports or kerfed or slot ports were being used, some of which were woofers and port back, and others woofers up port driver's side. The enclosures were certainly much more musical, with a much greater passband and keeping within near the same response level across the span of frequencies. However the larger it was, there was an apparent peak, which grew drastically peakier of course as the enclosure increased in size.
The best combination so far to my ears for music, then decent air being moved, and decent for numbers was 1.75 net per driver, both woofers and kerfed port firing back (iirc only in the low 30s of sqin of port).
The best combination or balance for numbers, air being moved, and pretty good sounding was the 1.75 net per woofer, firing upwards, and driver's side firing 8" aeroport.
These are my experiences; I feel like I have gained extensive experience for basic ported enclosures for these drivers and especially for trunk builds with them.
I suppose these would be cliffs of what I am after, above are mostly my experiences with the extensive amounts of enclosures I've built for them (easily 10+) and how they performed in my premise.
Now, the questions: Do these experiences with how they perform in basic ported enclosures have ANY bearing on a how to go about a 4th order enclosure for them?
For dual 12" driver 4th orders, where do most people start for enclosure specs?
Sealed and ported volume recommendations?
How much port area and what tuning is sought after for the ported section?
If I would like heavy output in the "lows," but not too low = useless lows, lol, say definitely the ability to play 30Hz+ with authority, heck even 28Hz+ with authority that'd be positively amazing, but I only made the mistake of tuning a ported enclosure around that (29.5Hz) and found out that musically it sucked (except was amazing for super low slowed stuff
) as it dropped off into nothingness after the lower mid 40Hz lol. Or if need be because of frequency response or characteristics being much different for 4th orders I would be fine with say ~33Hz+ or if it has to be 35Hz+ with authority while staying relatively close in response up to wherever it would go. As long as a spectrum or passband of 35Hz or higher in total could be covered without a large drop-off in authority I'd be quite happy. For example: authority 28Hz to 63Hz, or say 33Hz to 68Hz etc.
If the T/S specs scream hell no to a 4th order, would it be possible to recone the drivers with recones specified to be for a 4th order by chance?
If someone wants to help me out a lot, or even just a good bit with this, I will happily PP a few bucks. But I am not looking for a full-on design and having to pay $35+ or anything. Rather, a good amount of help per se instead. I can certainly pay for like a cut-sheet and what frequencies will be played, and other characteristics to expect. Of course, I understand that all will drastically vary for my build as this hobby is stupidly dynamic.
I can certainly post dimensions and other information needed, or PM or email.
Vehicle is an '08 Mercedes-Benz C300 Sport 4-Matic.
Woofers are Mach 5 SPL-12s dual 2ohm (Qty: 2)
Powered by an Orion 2500D @ .5ohm - However instead of ~3kW being used, I will probably be using 4kW or 5kW in the near future, possibly as soon as my other D3100 comes in. But we'll say the Orion for now.
Sorry for the immense, and intense rambles everyone! School is kicking my ass in full-bore already, and I have had wahaaayyy too much caffeine on top of my regular "study-study" medication for an all-nighter that I have to pull already!
Thank you all so much!