Couple of questions regarding boot install..., ... one of them is a little tricky! Options

[markjbutler]

Hi all,

I have just started a little project that i have been meaning to get on with pretty much since i got the car about a year ago and that is a neat and tidy boot install. I am going to build a box to house my 12" sub and also a pair of 6X9's at a later date. It will fit between the two suspension towers and be pretty much flush with them (I say pretty much, the plastic surround in the boot is more than vertical and i want to at least have a small angle less than square) and will be the full height of the back seats, replacing the parcel shelf. I will also add a hinged section on the back so as the parcel shelf is still usable.

I want to port each of the seperate cabinets. The main port that will be a rectangle of the equivalent area of a 3" circular port which will sit between the two 6X9's just behind the rear headrests on the top of the box. I am not sure as to what frequency to attempt to tune this to - I'm thinking between 20 and 25Hz as i like bass that you feel almost as much as bass you can hear or is that too low? To be frank both the sub and amp are nothing to shout about but will be replaced in future so a box that will work with mainstream mid-range subs is also something i need - what frequencies do most subs like to be ported at?

I have found a port calculator online which will tell me the required length of port based on the frequency i want to tune to but i also notice in its output data that it gives a volume for the port which leads me onto the more indepth question - can i simply use the port volume and build it angled so that it is shorter but still seperates the same amount of air as the uniform port of the length given by the port calculator? Hope you can follow that!!

Also I want to port the top cabinets sideways into the very top of the main port as to keep the visible surface of the box as clean as possible. I will have them offset from each other to try and stop some turbulence but do you think it would make the box sound funny in any way having the 6X9's ported into the opening of the sub port? I dont understnad enough about the waves enough to think if it would effect the sound - physics A-level wasnt in depth-enough!!

Anyway, my last question... this is easy after the other two! Does anyone know the angle between the boot floor and the back of the seats?

Thanks for reading if you still are - i will draw diagrams if people cant follow my descriptions.
Cheers