MJ-18's ports

[Roddy 0]

im working on a box for two mj18s and have a few questions

what size of port do i need for a box 4.5cf tune to 30hz?

would there be a big dif if the box was 4 cf instead of 4.5? ( my box is 9.36cf)

any building ideals or stats or thoughts would be great

thanks roddy

[turtles1118 1]

im working on a box for two mj18s and have a few questions

what size of port do i need for a box 4.5cf tune to 30hz?

would there be a big dif if the box was 4 cf instead of 4.5? ( my box is 9.36cf)

any building ideals or stats or thoughts would be great

thanks roddy

Home or Auto, if home about how many sq feet of the room, if Auto what kind of car/truck/suv and year? Is your box size 9.36cf or 4.5cf?

[Roddy 0]

2001 exploder suv box size about 9.36 with out any bracing or port or sub

i was told to use 1 box with both drivers

but i think 1 box with 2 separate areas would be better

[///M5 2,833]

I disagree on the one box with separate areas. It is nice to have a bit of "averaging" when using dual drivers and the only real way to do this is to put them in the same enclosure. Of course an enclosure that is 9.4 cuft needs a ton of bracing.

As to your question, yes there will be a big difference between 4cuft and 4.5cuft. Have you already built the box? Normally I account for port length and size before figuring out the total volume of the box, it makes it much easier.

[turtles1118 1]

2001 exploder suv box size about 9.36 with out any bracing or port or sub

i was told to use 1 box with both drivers

but i think 1 box with 2 separate areas would be better

I agree With ///M5, one box for the too MJ-18s would sound a lot better, each driver is about .25 cf, what are the measurements of the box? I have put 2 MJ-18s in a 2003 Trail Blazer with a box that was around 10.0cf tuned to 32hz, and about 800 watts going to each one and they sounded amazing.

[Roddy 0]

so with bracing and no sub my volume of the box is16517.187inches cubed

what do you think i should tune it to?

i was told to tune it to 43 hz for most spl but i think 30 hz would sound better

what size of port should i use? the box is like t shape and theinside is 38" wide

any help would be great

[turtles1118 1]

so with bracing and no sub my volume of the box is16517.187inches cubed

what do you think i should tune it to?

i was told to tune it to 43 hz for most spl but i think 30 hz would sound better

what size of port should i use? the box is like t shape and theinside is 38" wide

any help would be great

Are you going for spl or daily driving, if spl then about 40-47hz sounds good but if daily you want to go around 30-35hz

30hz=about 130 in3

45hz=about 255 in3

Edited August 7, 2007 by turtles1118