[White fish]

I’m try to build a box for my trunk but don’t want to give up to much space
I have a Alpine Mrv-m250
Plan on using 1 or 2 Skar ix8

I want to build a wedge box my max size
35” wide 16” tall but only 9” wide at bottom and 2” wide at top

Im hoping someone can run the numbers for me Sealed or vented 1 or 2 subs

 

[Jheitt142]

download speaker box lite from the app store. It'll do it for you and they have the Skar woofers in the pre loaded database

 

[White fish]

I feel so dumb
I downloaded it but in lost

 

[Jheitt142]

I feel so dumb
I downloaded it but in lost

dont, it works well but its not what i would call user friendly, especially on a phone. might not be too bad on a tablet. I find WINISD easier to use

 

[Jheitt142]

I did PM you but i'll keep it here for the google machine.

Alright, using 3/4" thick material you have 1.15cuft net. With 1/2" you're at 1.36cuft

IMO the 1/2" buys you enough space to be worth while a single brace from long sheet to long sheet would handle any flex. I've never had an issue with lower powered subs in 1/2" boxes. You have to go ported with these to even bother using them. build the box to your max dimensions. do you want a slot port or round port?

 

[White fish]

I think I prefer a port on the same face as the subs (facing into the trunk) because the ends are to close to the sides too
I think a slot would be better looking
Bracing is no problem

 

[Jheitt142]

I think I prefer a port on the same face as the subs (facing into the trunk) because the ends are to close to the sides too
I think a slot would be better looking
Bracing is no problem

fair enough. give me a bit again here

 

[Jheitt142]

I've based everything so far off 2 subs. Using 2 you wont fit a slot ported enclosure in that space with tuning that will actually be useful. round port can work. If you want a slot port you should drop to one sub.

 

[White fish]

I can do round port if that works better

 

[Jheitt142]

In reality in that space I'd take a single sealed 12 over 2 of those 8s. If you are set on the Skar stuff, a single IX12 sealed or a single IX10 ported will do well in the space you have.

if you want to stick to the 8's a single 3" port 9.5" long should get you an FB around 35hz and an F3 around 30hz accounting for some cabin gain. obviously you'll need a 90 in there but easy enough.

 

[Grinder]

I've messed around a bit with IX-8s, both sealed and vented (none in-car though). Of course, output and extension are far greater vented.

I built two pairs of home towers, one pair with 2ea. sealed IX-8 D2 in 0.5 ft^3 ea., and one pair with 1 ea. vented IX-8 D4 in 1.0 ft^3 ea. at ~39Hz, with an 11" long 3" aero port: Home

Sealed need a ton of PEQ for any extension, but four of them aren't half bad. Vented are far more effortless, and just the pair of them have surprising output.

Having said all of that, I had some wacky ideas when I bought a bunch of IX-8s back in 2015, before I had any clue at all what I was doing. If I had it to do over again, I would have gone with Dayton or Image Dynamics, for far superior sound quality and better all-round performance and value.

@miniSQ absolutely swears by a pair of Image Dynamics ID8s in 1.6 ft^3 ported with a pair of 3" diameter ports 15" long. I'd definitely give that a try if I could.

...or you could go with one ID8 and one 3" x 15" port in 0.8 ft^3.

 

[Jheitt142]

I've messed around a bit with IX-8s, both sealed and vented (none in-car though). Of course, output and extension are far greater vented.

I built two pairs of home towers, one pair with 2ea. sealed IX-8 D2 in 0.5 ft^3 ea., and one pair with 1 ea. vented IX-8 D4 in 1.0 ft^3 ea. at ~39Hz, with an 11" long 3" aero port: Home

Sealed need a ton of PEQ for any extension, but four of them aren't half bad. Vented are far more effortless, and just the pair of them have surprising output.

thats what found when modeling them. they are more of a great midbass driver when sealed.

 

[Grinder]

thats what found when modeling them. they are more of a great midbass driver when sealed.

Yup, that is pretty much the case without gobs of PEQ ...except for the "great" part.

<edit>
Ask me how I know... As it happens, the sealed IX-8 towers each have a RF PPS4-8 (8" pro "midrange/midbass") and a PP8-T bullet tweeter, and those pro 8s are about as naturally suited to midbass as the IX-8s are to sub-bass (I bought the RF pro stuff shortly after the IX-8s; and like I said, I had no clue at all what I was doing back then, LOL), so I eventually tried high-passing the IX-8s for midbass duty while taking up the low-end with a Paradigm PS-1200 I've had since the early '90s. In the end, it just sounded best while taming the PPS4-8s with PEQ and forcing them to make midbass, and PEQing the hell out of the IX-8s, which just seem to sound worse and worse the higher I try and play them. However, for max output at a party or the like, I would definitely high-pass the IX-8s for midbass duty, and run my pair of Dayton HF15s for sub duty.

Apologies to OP for derailing the thread.