Sealed or Ported?

I want to power two Kenwood KFC-W3009 800W subs from a KAC-8151D 1000W mono amp.

I'm going to place the subs in the trunk of my W123 series Mercedes. As some might be aware, these cars' trunk are tigthly sealed - behind the back seat is a sound deadening carpet and metal firewall, with the fuel tank placed behind the firewall. The only type of direct access to the trunk is through the holes of the rear-deck speakers. Another opening could be made by removing the first-aid kit's housing, although I don't really want to do it.

I'd like to know which type of sub-enclosure should I use - sealed or ported? I want natural, tight bass from the system. I currently have a double sealed enclosure (about 1.8 cubic feet) available (haven't installed it yet), but I don't know if it's big enough. The subs' manual recommends 1 cubic foot per sub for a sealed setup, 1.5 cubic feet per sub for a ported setup.

I don't want to sacrifice too much trunk space.

Any advice will be appreciated!

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F R A N S
1985 Mercedes-Benz 230E
320 000 km / 199 000 miles
Full MB Service History

I've always wanted to experiment with building a box in the boot (trunk) loading the subs backwards and porting into the car itself maybe throught the centre of the shelf.  You could try it and let me know.

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WOW Sight and Sound
Maroochydore
Nothing is impossible!
Do it right the first time or don't do it at all.

Sounds to me you are looking for sealed, if you want quality, and not pure spl. Sealed will also take up significantly less space.

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99 Blazer LT.   Yellow Top. Big 3. Infinity Kappa Speakers All Around. Jensen CD/DVD flip out. 2 Infinity Kappa Perfect 12DVQs powered by a Alpine PDX600.1 (in one custom box, building a FG box)

Try it with the enclosure you have on hand, but be prepared to build a new one if the bass isn't deep enough.  Just that extra 1/4 cu ft can make a big difference in low end response.  I would suggest, too, that you remove the rear speakers and leave the openings through which the sub bass can easily enter the cabin.  Make sure you damp the parcel shelf while you're at it to prevent noise from the vibrating sheet metal.  You will have to modify the baffle under the rear shelf that separates it from the trunk to allow sound wave passage.  Or you can remove it altogether.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Stick with a sealed enclosure. It's not going to sound too great with a vented enclosure in a trunk. You want SQ anyways and want to take up as little space as possible so the sealed is the perfect match for you! Stevdart is right, go with the box you have already. You said that you like tight bass so that box might just be to your satisfactory. If it is too tight of bass and isn't hitting low enough, then go a little bigger. It is also a good idea to leave some airspace through the back. Either leaving the speakers out to let airflow out like stevdart stated, or you could make ports by cutting out a hole in between the speakers on the rear shelf. Cover it with a mesh cloth or some type of material that is very breathable to cover up the hole so it looks unnoticeable. I've seen that done on a couple different vehicles. Not only looks sweet but sounds great too!

stevdart wrote:

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Try it with the enclosure you have on hand, but be prepared to build a new one if the bass isn't deep enough.  Just that extra 1/4 cu ft can make a big difference in low end response.  I would suggest, too, that you remove the rear speakers and leave the openings through which the sub bass can easily enter the cabin.  Make sure you damp the parcel shelf while you're at it to prevent noise from the vibrating sheet metal.  You will have to modify the baffle under the rear shelf that separates it from the trunk to allow sound wave passage.  Or you can remove it altogether.

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Just be careful with this as your gas tank is right underneath that shelf IIRC.