Two Questions Regarding Rear Seat Box Design [PICS]
Hi guys, I'm in the process of fabricating another enclosure for two Sundown Zv3 15s and I have a couple of quick questions.
First off, the enclosure I am building is of a composite construction. There were several considerations I took into mind:
- The trunk is sealed by a firewall from the cabin so it's impossible to do a trunk "blow through". Additionally a 4th order was not feasible due to the gasoline tank being directly behind the rear seat so I couldn't run enough port.
- Given this, I decided to make the box on the rear seat and try to keep the subwoofers firing forward as pushed back as possible from the listener.
- Additionally, I wanted to maximize air space so I created molds of the seat contours upon which to Build the box. This also keeps the enclosure profile and center of gravity fairly low. As a bonus the box is removable. Each mold is 6 layers thick and has a capacity of 0.89CF as measured using 2L Coke bottles. It's also quite strong as it's passed the "stand on it" test.
As it sits now, the each enclosure is calculated to be 4.37CF gross (3.6cf after port and woofer displacements).
I have a few questions regarding two proceeding steps:
1) Since the box is relatively large and the back wall is 45cm long I plan to use this to run a straight port firing rearwards (8cm tall x 35 cm wide; 35Hz tune). Additionally, since the box is cut at a 69 degree angle it should taper perfectly into the contour of the mold giving me even more effective length.
The question is, in the past I've always ran my ports on the same face as the woofer. Do you think firing upward like this will be an issue? I'm thinking it could be good in the sense that the port will load somewhat close to the rear glass. On the other hand, there will be a 20" distance between the woofer and the port which may cause some strange inteference/cancellation issues.
2) Since I've got the wood cut I'm noticing some light 0.5mm discrepancies on the mating area of the FRP tray frame and the the upper MDF box structure due to high precision required to cut the front baffles at an angle (it's good but not perfect). I'm going to do my best to plane them down by hand with a long sanding block however I still anticipate some slight gaps. Do you think the glue good enough to fill these gaps? I plan to use Titebond III. Otherwise, I'm thinking after I glue it, I will proceed to reinforce this joing between the two with 2-3 layers of FRP? What to you think? Necessary or overkill?
I've attached a few pictures as it's coming along.
Re: Two Questions Regarding Rear Seat Box Design [PICS]
I don't see any issues firing up. Your not going to see any weird issues as the wavelength of the sub freq are so long.
The glue will be WAY stronger then your MDF so I don't see a issue just using glue at all. If your worried about large gaps you can mix MDF dust from your cuttings/sanding and mix it with the glue to form a paste. Homemade wood filler
It also wouldn't hurt to reinforce this seam as well. If you have the stuff to do it I would
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