Enclosure For 2 1508s in an 08 Infiniti G35 Sedan

[BlackG35inTN]

Hey everyone. I'm the former member on here known as BlackFx4inTN. I sold my truck and now have a new ride(hence the name change). I pulled all of gear out of the truck and I am in the begining stages on designing an enclosure for my (2) 1508's. I'm not exactly sure what I want to do with this and figured this was the place to get some insight. Max enclosure size would be

31.25"w x 17"h x 11"d. My 3 options are:

1) ported- tuned to 32-35hz subs firing twords the trunk, port firing to the side of the trunk (vertically in rear of enclosure)

2) 4th order- Three Chamber single reflex bandpass - port firing into the ski hole / pass-through which is 6" x 12", via square MDF or 4" precision port

3) Downfiring- subs (obviously firing down) port firing to the side at the top of box horizontally.

I have a design made up in sketchup of the 4th order. Both subs would be sealed in 0.948 cuft of airspace each, into the ported chamber which would be .51128 cuft. This is where I am stuck. Since DD is stingy with their t/s parameters, I'm not really sure how long I should make the port using winISD.

I can get by with just a basic ported enclosure and have no problem designing one of those, but if some of you guys with more experience than me would like to draw up something using my max dimensions, feel free. 11 inches is the deepest I can go due to the trunk opening, unless I figure out a way to take the back seat apart (which doesnt fold down), and bring the enclosure through the passenger compartment.

These are 4 ohmDVC that will be pushed by an AQ2200. Thanks for your time or any ideas.

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[surreal 10+ year member]

Oooh awesome build. Let me do a 6th order for you!

 

[BlackG35inTN]

I didn't really want to go with a 6th order due to the narrow bandwidth. This will be a daily driver. It sounds like a fun enclosure to build though(and i will be building it). I respect the hell out of you guys that can build/design these things right. But 6th order isnt for me.

 

[surreal 10+ year member]

No disrespect but as a designer it is my job to choose which enclosure best fits your design goals. A 6th order will be better for those woofers than a 4th order. They are strong little subs that like small boxes. A 6th order designed properly will give you good bandwidth and better output than a comparable 4th or ported enclosure.

 

[adas Pro Seller]

woahhh, well if anything with the 4th order make the sealed chambers around .5 if not less each, and around 1.5-2cu ft for the ported at 42-45hz. depends how you really want it to play. but i deffffff say go skihole blowthrough route. loudest if done right, and NO trunk rattle FTW.

but i do agree with surreal, 6th order will work great but picky as fawk with making a box with decent bandwidth.

 

[BlackG35inTN]

woahhh, well if anything with the 4th order make the sealed chambers around .5 if not less each, and around 1.5-2cu ft for the ported at 42-45hz. depends how you really want it to play. but i deffffff say go skihole blowthrough route. loudest if done right, and NO trunk rattle FTW.but i do agree with surreal, 6th order will work great but picky as fawk with making a box with decent bandwidth.

See, I always thought the same way in 4th order (having the sealed chambers small / ported chambers big) but the more bullshat you read online tends to corrupt your line of thinking. Yes, I would love to go sixth order if there would be no problems with the bandwidth.

And surreal, no disrespect taken. That is one arena I'm a total noob in. What kind of 6th order were you thinking?

 

[surreal 10+ year member]

PMd.

Adas.. guessing you havnt much real design experience saying a 6th order would be picky to get bandwidth from. I can guarantee any 6th order I design will have better usable bandwidth than your 4th order, because your 4th order is going to be very peaky. Especially with both chambers so large, and a decently strong motor on a little piston..

They both have good potential. But I design my 6th orders, 99% of 4th orders around here are guesses. Misinformation is bound to spread.

Edit - Not to mention on an AQ2200 he will need all the power handling he can get..

 

[adas Pro Seller]

More power to getting a good 6th order going for him. in my experience, i dont like the way 1508's play in a smaller box, i like lows and for that i gotta sacrifice a little power handling with these little guys. I've also made a few 4th orders. tried one that basspoxpro recommended size wise that was just that, small ported chamber and larger sealed with a couple different 8's, then 10s. sounded like ShAt. so for the ones ive been, as long as i keep ratio under 2:1 port area dependant im very happy with the way they play.

6th orders another ball game for me though, had one designed for me for 3 1508s, but never I finsihed the build because i told myself no way it's going to be loud with that little of port. maybe one day I'll finish it and see.

 

[surreal 10+ year member]

Ah, good to hear youve done a bit of testing then.

Im not sure how much Id trust the 6th order. They are complicated enclosures, and they are hard to design. I definitely wouldnt accept a design for one off of just anybody on the forum.

Was it a parallel or series tuned enclosure?

 

[Moble Enclosurs 10+ year member]

The 1508s are naturally spl drivers. I have designed many enclosures for them myself as well. The 6th order design is great for controlling their resonance sensitivity. But it has to be mentioned as well, that we need to concentrate on not only the box response but the transfer function of the environment as well, in which a 4th order might work well in, givin the space may be compact enough for LF resonance to increase efficiency below the natural resonance of the enclosure/box response. That being said, it is a great idea to explore both and more options of design ideas. You may find in some cases, the bass reflex may be optimal, which will save money and labor and materials in the end. But has to be calculated for at the least before concluding it null.

Cabin response will make or break a design in some cases, and the larger the room the greater the significance.

 

[Moble Enclosurs 10+ year member]

More power to getting a good 6th order going for him. in my experience, i dont like the way 1508's play in a smaller box, i like lows and for that i gotta sacrifice a little power handling with these little guys. I've also made a few 4th orders. tried one that basspoxpro recommended size wise that was just that, small ported chamber and larger sealed with a couple different 8's, then 10s. sounded like ShAt. so for the ones ive been, as long as i keep ratio under 2:1 port area dependant im very happy with the way they play.
6th orders another ball game for me though, had one designed for me for 3 1508s, but never I finsihed the build because i told myself no way it's going to be loud with that little of port. maybe one day I'll finish it and see.

You cannot judge the port size based on soley asthetic appeal, though some do have good eyes for it. You may be surprised that sometimes, for smoother responses and lower frequency cutoffs, that a smaller port may be sufficient. But the designer has to consider port noise as a factor, and not by using a program. There exists a formula that I use to enable for proper port area, instead of saying,"make it as big as the driver surface ares", or " make it half the surface area". Sometimes, with drivers like the 1508, a more controlled output is needed. So, though I do not know the exact design you mentioned, do not underestimate the ability of a smaller port,lol. They can surprise you if done correctly.