i was wondering if you guys would help me get my port lengths and areas down. i just reciveved my btl 18" yesterday and looking to build the box right now i am looking at having a 7 cu ft after displacemnet. i alos think i want it tuned to about 32 hz. i t will be square port

When you say "7 cu ft after displacemnet", I assume you mean just after woofer displacement, since you don't know the displacement of the port yet. . .

The best thing would be for you to post up some dimensions and we can help you with a box design. Knowing the box dimensions is pretty much a requirement to determine the port size and length.

Brian

Edited July 2, 200817 yr by BKOLFO4

alright my max dimensions would be 58 x 21 x 22 but that comes out to be like 12 ft cu that would be to big. could you recomend me to what size and what port area and length to use

do you have a problem with those dimensions because i think 12 cu ft -woofer displacement + port disp. would be fine.

alright my max dimensions would be 58 x 21 x 22 but that comes out to be like 12 ft cu that would be to big. could you recomend me to what size and what port area and length to use

wait that works out to be 15.5 ^3 ft

okay..new thing..heres what i got for ya 50 x 21x22 .after calculating total internal vol..i got 11.08^3 ft including port displacement..all u gotta do is subtract woofer and bracing volume.the port will be height(hv)=8,width(wv)=9and length(lv)=10..this gives a fb of 31.83 hz.here are the cut list if u need..Square Prism Box Parts

1 Top, 1 Bottom: 22 © x 21 (b) in

0.75 (thick) in

1 Front: 48.5 (a) x 19.5 (d) x 1 (thick) in

1 Back: 48.5 (a) x 19.5 (d) x 0.75 (thick) in

2 Sides: 48.5 (a) x 22 © x 0.75 (thick) in

Vent Parts

1 Top, 1 Bottom: 9 (e) x 10 (h) in

0.125 (thick) in

2 Sides: 8.25 (g) x 10 (h) x 0.125 (thick) in

hope this helps..this was plotted using bassbox pro 6.

I'd like to help you out,

I need to know if those are internal dimensions or not

I need to know which dimensions are which (h)x(w)x(l)

I also need to know which side you want to put the port on.

thanx mecalli for you info now for you seductive. these are max external dimensions length equals 58in width equals 22 inch and height equals 21in and for the port location i would like it on top

with the sub firing up as well

also i was wondering how much bracing do you think ill need and how to do it thanx

if you need i can post a pic of the truck that its going in so you can get more of an idea of what i going for. its a ford f150 97 with the back seat out

thanx mecalli for you info now for you seductive. these are max external dimensions length equals 58in width equals 22 inch and height equals 21in and for the port location i would like it on top

with the sub firing up as well

also i was wondering how much bracing do you think ill need and how to do it thanx

if you need i can post a pic of the truck that its going in so you can get more of an idea of what i going for. its a ford f150 97 with the back seat out

I'd like to help you out,

I need to know if those are internal dimensions or not

I need to know which dimensions are which (h)x(w)x(l)

I also need to know which side you want to put the port on.

naw not internal.......height=21 x width= x length= 50..the port can be placed anywhere 90 degrees on any of the sides ,parallel to the baffle and bottom.

thanx mecalli for you info now for you seductive. these are max external dimensions length equals 58in width equals 22 inch and height equals 21in and for the port location i would like it on top

with the sub firing up as well

also i was wondering how much bracing do you think ill need and how to do it thanx

if you need i can post a pic of the truck that its going in so you can get more of an idea of what i going for. its a ford f150 97 with the back seat out

honestly ..i think you should reconsider placing your port on the baffle....firing it off axis will yield a somewhat louder effect in that vehicle ....fire the sub up will be nice ...if you face the port rearwards ..you may get a little advantage of the horn effect ..which tends to yield a couple db's. however ..this is just an opinion ..not what you have to do.

I worked out 7.5ft^3 after all displacement

Outside Dimensions:

44 (L) x 22 (W) x 21 (H)

Port Dimensions:

22.75 (L) x 20.5 (W) x 6 (H)

Tuning works out to 32.37 Hz

Edited July 5, 200817 yr by SeductiveSounds

hey seductive woudnt your dimensions for the port be to big 20.5 x20 would be like 400sq in of port isnt that to big for my one 18

no it's 6 x 20.5 = 123 square inches of port

the 22.7 is the length of the port...

isn't that port length to big for my box

What do you mean to big ?

nm its not to big put with a port 22.75 inches of length it would take up more than have of the face on the box which is 40 in. is this how its supposed to be. it might be its just i really dont understand which port dimension is which

Sorry if it was a little confusing.

Here is a pic of what I was thinking

o ok i see now thanx that helps alot but i still cant see how the length is 22.75 if the box depth of that box on that side is only 22

L-shaped port.

I think my math is a little off.

I think I calculated for the double baffle being on the pot side on the inside.

That'll throw the tuning off a little bit (making it a little higher, around

Make the port 30" long it'll tune the 32.27Hz

My bad

That box looks good but i think i would put the sub on the drivers side and the port on the pass side