Thinking about making a subwoofer enclosure that will house the speaker in a down firing position. It will fit in the trunk area between the struts. The enclosure will be elevated about 1 inch of the trunk floor. Much like the subs sold for home theater use. I'll probably use a 12 inch sub and run about 100-200 watt amp.

Has anyone had any experience with this type of system (down firing) in their FD??

 

do you mean with the cone facing upwards? if so, there is no sound difference between this (btw, this fact is true...i i have a car audio mag in front of me and in the q/a section this question is asked)

 

Nope, the sub is mounted "upside down" with the cone pointed at the floor.

If I were you, I'd raise the height of the enclosure up to at least 2" because you run the risk of the cone hitting the floor, especially if you're running a high excursion sub. Low notes and playing the music loud will do it! See here.

And, for a 12" sub, you're grossly underpowering it with only 100 - 200W. Your typical 8" sub can take 300; I'd look to run at least 500.

 

In a car I would not down fire the sub for two reasons:

The footprint of the enclosure is larger than it would be if the driver was side mounted.

With a high powered driver firing directly at the floor you'll get all sort of vibrations and rattles throughout the car.

Homes don't have either of these problems.

 

yeah... thats what i mean... but what i said was true at the top

 

I'd suppose most home systems are setup that way simply because the driver is less likely to get poked by something down there, as opposed to the sides.

 

I have a 10 firing downwards at the moment in my series 3 (i think you yanks call them GSL-SE) and it sounds alot better than when I was trying different boxes for my 15. Sounds very tight and you can hear it more outside of the car than any other sub positions i have tried (which is about every position).
It's around 1 inch off the floor.

 

Exact same principle(s) would apply to this type enclosure placement in the trunk. I'll build it this week-end then post the results. Thanks.

 

I bought a cheapy RadioShaco 12' that is rated 200 watts at 8ohms. So I think a 200 watt amp will suffice. Plus not looking to entertain the whole neighborhood while I listen to barry manilow (just kidding) .

 

Cool. This should be intersting.


I gave this some more thought. Most, if not all, of the home down-firing subs, are meant to be hidden out of the way and run in a single corner of the room. The downfiring position helps to mask any directional perception of the bass coming from the cone, and rely on corner loading to help disperse the bass over the room.

This is purely anecdotal, but then again, so is most of the speaker market.

I'm speculating that the perceivable difference between mounting directions is due to blocking the front of the driver with carpet, effectively damping it (and therefore changing the resonance characteristics of the system).

Another important factor to consider is the physical coupling between the enclosure and the car body, like carpet vs. the plastic on the rear compartment divider. That and the dimensions of the box can change how transversal, longitudinal and lateral waves transfer within the box, into the car structure, and sum up with chamber resonance of the car to give you a final product.

 

Sounds (no pun intended) like you're a hard-core audiophile. The enclosure will not be made in a perfect cubical, squared dimension. It will be angled in the front (where it meets with the trunk divider) and also angled towards the rear(facing the rear lights). This angled piece will also be the platform that will maintain the AMP. I'm thinking of creating a single port on one of the side panels so help distribute the lower sound waves, but I'll wait to hear the final result before I decide to port. The enclosure be positioned between the rear strut towers. I plan on wrapping the entire enclosure in black leather-like vinyl. I'll post a few photos of it out of the FD, and how it looks installed. Thanks a lot for your input.

 

I finally got to it today. I finished the enclosure but was not able to place/glue the black viny cover on it. I'll do that first thing tomorrow a.m. Then I'll go to best buy or circuit city and see if I can find an 200 watt amp with an aluminum body. The amp will be placed on the front portion of the enclosure so that when the trunk is lifted, you'll spot the amp immediately.

I connected the the woofer/enclosure and the 40 watt amp (p-o-s) to the radio and it sounds pretty impressive. I ended-up making two ports next to the woofer. That seems to have worked out okay. I'll post a few photos of it on Monday.