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View Full Version : Sub firing into open chamber opinions



Psydwaze
04-01-2008, 12:18 PM
I'm looking for opinions or any experiences with this type of box design.

This design is for a AA Assassin 12, 2.2 cu. ft. @ 33hz. Rear firing in trunk of 1998 Honda Civic. The purpose of the chamber is to protect the cone from skateboards, scooters, groceries, or whatever else finds its way into the trunk.

My train of thought is that the open chamber increases and equalizes distance to the rear wall of the trunk as compared to the port. And will minimize cancellation from a sideways or upward firing sub where some soundwaves travel directly into the passenger area and some are reflected from the backwall of the trunk.

Opening of the chamber is roughly 70 square inches or about 60 pecent the surface area of the speaker cone.

http://i279.photobucket.com/albums/kk141/Psydwaze/ported_box_12-inch_sub.jpg

Heavy Hitta
04-03-2008, 08:50 PM
Whell im not to shure what your asking, but i built the same exact box for a 15" for my house stero, anyway....much louderr and cleaner

60ndown
04-03-2008, 08:53 PM
my subs are in my work van and i build boxes like that for the same reason (tools not skateboards) just dont get the end pannel too close to the sub, leave at least 4 inches and youll be good. they sound great because the end pannel actually 'loads' the sub = better sq.

Trey803
04-03-2008, 08:55 PM
you will have waves hitting the cone which I believe causes distortion........principle behind deflex pads. Maybe not as big a factor for low notes as mids and highs

60ndown
04-03-2008, 08:57 PM
you will have waves hitting the cone which I believe causes distortion........principle behind deflex pads. Maybe not as big a factor for low notes as mids and highs

is that why almost every home theatre sub you can buy is downfiring?

= you fail;)

60ndown
04-03-2008, 08:59 PM
follow the links to the 'speaker' page here

look at the subs,

many of them are 'loaded' on panels

http://www.decware.com/newsite/mainmenu.htm

mdillon
04-04-2008, 12:32 AM
my subs always fire down in my installs. mid 140's with a downfired xxx on about 1600w. it allows for higher output at lower frequencies also.

Psydwaze
04-05-2008, 11:47 AM
Great feedback guys. Thanks.

I guess I was just looking for some confirmation on firing the sub into a panel before beginning my build. The home audio examples show that its an accepted loading method, so now I feel better about my design.