IXL-18(s) in car?

[mrogowski 6]

250 is indeed large, but if you are pumping 2kw into them you don't want any whistling through it. 120 would probably generate too much noise. How much power do you have on tap?

If you want to go smaller, do 175 sq. inches 14 inches long. Total volume is is about 1.4 cubes, which leaves the subs with 22.5 cubes to work in. Mach speed is still high at around 22m/sec, but you may not notice it.

Let us know what you do...

[RAD 0]

Have 4kw on tap, but gains are set very conservatively so they'll see far less. A little port noise i can put up with, but not if it wheezes and farts at every note. Not that 250 doesnt work too bad, but the woofers dont like my windows being all the way down, or a door open, and the tuning seems to be far lower than 30hz. Anyway, i'll experiment with some ports today, and see how each sounds in the car.

[mrogowski 6]

Yeah, you're in a good position since you can adjust without having to rebuild. I use WinISD Pro to calculate vent size/tuning. I found it to be bang on, through actual measurements. Just an FYI if you want to run some simulations yourself..

m

[RAD 0]

Just an update, i'm using the 175sqin port you suggested before. Sounds great, not a hint of port noise, from 35-55hz it sounds as good as my old DD9512, but can still rock notes from 35 to the low 20's.

We metered it last night, 144.4 @ 43hz. We dont think the stores meter was accurate, as two other walled guys got within .2db of this, and trunk/hatched cars got low scores with similar figures of 128/133 respectively.

Some minor port tweaking (possibly a bit lower) and a possible cancellation issue (inside the wall is very quiet) should see a very musical 150db sytem on my hands

P.S. the IXL 18's seem to be catching on in Oz, i know one guy just brought 4 of them for his wagon!

[mrogowski 6]

I'm glad to hear things are working out better. Not sure what exactly you're going after but if its loudness, tune higher...

[SPLChris 0]

With that much space, why not a bandpass? Put them in sealed boxes and have them fire into a loading wall. Make the port as big as possible then shrink to how it sounds best.

[RAD 0]

I'm glad to hear things are working out better. Not sure what exactly you're going after but if its loudness, tune higher...

I'm not after pure numbers on a meter, i'm after a Jekyl and Hyde car: nice, low musical setup for just driving quietly around the streets, but heavy, painfully loud bass when i want to show off at meets. That, and i think theres some satisfaction in getting maximum sound levels by putting the work into the install, not throwing money at it i.e. like the $15-20K Digital Designs installs in this country. Learning what works and gaining skills for the next build will be good too

With that much space, why not a bandpass? Put them in sealed boxes and have them fire into a loading wall. Make the port as big as possible then shrink to how it sounds best.

Never played with a bandpass box before, it'd be fun to experiment with loading walls and such/ but from what i understand, your enclosures have to be painfully precise or they fail?

P.S. the wall has a divider in it now, so essentially each sub is in its own enclosure. Made a noticable gain, so i'm progressing along as far as getting more SPL is concearned.

Edited July 22, 2008 by RAD

[SPLChris 0]

4th orders are WAAAAAY more forgiving than 6th orders and higher up and with that much space they aren't that more difficult than a ported enclosure. The front chamber is where you'll get all the efficiency, the larger the better. Your sealed section will determine your lower cutoff frequency and essentially how much power the subs can take. The larger the sealed section the lower it will play but at the expense of power handling. My 12's with the small sealed section sound AWESOME but I also don't listen to anything under 30 hz. With a ported wall that large, the subs will come close to the mechanical limits pretty quickly. With a 4th order, the sealed section will control the subs a lot better and you can reap the benefit of having a humongous port. A bandpass wall will destroy a ported wall. I would definitely consider it if I were you

[RAD 0]

It's something i'd consider, but i've no idea what figures i ought to be shooting for, and how the whole thing should model. I've opened up WinISD, tryed a few figures, seems like if i have my 3 subs with 7cuft rear, 11 ported @ 40hz, i'd have 96db+ from 30-55hz, reaching 100db at tuning freq. Sounds a little too good to be true?