Consider using aeroports. They are more costly, but you can typically get away with less port area due to their flaring.

how many, what size and how long do you think they will have to be?

is that with 1 inch walls or 3/4 inch walls?

edit: to Ricksi30

1"

do you think 3/4 inch with double baffle and little bracing will get me at least 4 cubes with 75 in^2 port? tuned at around 33.3?

do you think 3/4 inch with double baffle and little bracing will get me at least 4 cubes with 75 in^2 port? tuned at around 33.3?

Yes you could be right around there, just depends on how much bracing. Use wooden dowels or all thread to save space.

is that with 1 inch walls or 3/4 inch walls?

edit: to Ricksi30

1"

do you think 3/4 inch with double baffle and little bracing will get me at least 4 cubes with 75 in^2 port? tuned at around 33.3?

Yes you could be right around there, just depends on how much bracing. Use wooden dowels or all thread to save space.

idk how to brace with all thread so i was thinking 1-2 inch wood dowels.

idk how to brace with all thread so i was thinking 1-2 inch wood dowels.

That will work fine. If you port between the two subs that will help brace it too.

I take that back. Two of their 6" kits wouldn't be enough, and third would be too much.

are there any disadvantages/benefits of doing single chamber over double with center port?

I take that back. Two of their 6" kits wouldn't be enough, and third would be too much.

maybe 4 inch? idk, never really messed with aeroports. are they hard to install? how do you do it?

I take that back. Two of their 6" kits wouldn't be enough, and third would be too much.

maybe 4 inch? idk, never really messed with aeroports. are they hard to install? how do you do it?

You would need a lot, so it doesn't make sense.

I take that back. Two of their 6" kits wouldn't be enough, and third would be too much.

maybe 4 inch? idk, never really messed with aeroports. are they hard to install? how do you do it?

No you would need way too many 4" ports. Aero's probably won't work in this scenario.

I take that back. Two of their 6" kits wouldn't be enough, and third would be too much.

maybe 4 inch? idk, never really messed with aeroports. are they hard to install? how do you do it?

No you would need way too many 4" ports. Aero's probably won't work in this scenario.

yah thats kinda what i thought, was hoping maybe four four inch across the bottom would work but, oh well. Damn, well time to rethink things. BACK TO THE DRAWING BOARD!! haha

anyone have anykind of design ideas?

or actually, how many four inch aeros would it take? if they were all across the bottom it'd be cool. it'd be a lil extra cash but itd be worth it. would i have enough airspace after?

ok how bout this, 1 inch mdf, 40.5 inches wide, 20 inch depth, 17.75 inch height. Side firing port thats 5 inches tall x 18 iches wide. my calculations may be off. will model in sketchup for reference

tuning is at about 31.61 htz

Edited October 6, 201212 yr by NickHall

ok how bout this, 1 inch mdf, 40.5 inches wide, 20 inch depth, 17.75 inch height. Side firing port thats 5 inches tall x 18 iches wide. my calculations may be off. will model in sketchup for reference

tuning is at about 31.61 htz

Nope. Well under 3 ft^3 net.

Plus it really doesn't make any sense to use 5" for height when the enclosure height is 17.75". Quit using 1" MDF, your already limited on space, and that's not going to help.

0.75" MDF

40.5" width x 17.75" height x 20" depth

double baffle. Presuming the baffle panel is 40.5" x 17.75"

port width: 5", port height: 15.5". Fits with the height of the box. 77.5 in^2 port area

Port length: 34.25"

tuning: 33.5hz

net volume 4.27 ft^3

Throw in some dowel bracing, and your still over 4 ft^3.

Edited October 6, 201212 yr by stefanhinote

That sounds like a really good idea, and i started messign with my calulations with .75 inch mdf an yah im gonna go with that.

On that design you just came up with, is the double baffle on the back with the subs back or the front? if its the back then that cant be done. there isnt enough room between hatch and box to do subs back without modifying the box. I can do sub up or sub forward.

Thank you for all the help so far, i really appreciate it.

Edited October 6, 201212 yr by NickHall

ok so i used sketchup to design the enclosure you mentioned to the best of what i could tell you were saying.

Did i do it right? is it tuned correctly? whats it tuned at?

Oh and i think i kinda went overbaord on screenshots, lol

any input on the box would be appreciated. id like extra confirmation before i build

When I posted the previous numbers I thought it was back firing, so I calculated for a different displacement from double baffle, but don't fret:

With what you posted just change the port length to 36", and you'll end up with 33.5hz tuning, and 4.08 ft^3

Looks like your all set.

when you say change it to 36" is that short enough for it to not have a bend or will it have a bend?

and is the volume accounting for woofer displacement? its not much but do you think it will affect anything?

Thanks for all your help by the way. i really appreciate it.

Edited October 7, 201212 yr by NickHall

when you say change it to 36" is that short enough for it to not have a bend or will it have a bend?

and is the volume accounting for woofer displacement? its not much but do you think it will affect anything?

Thanks for all your help by the way. i really appreciate it.

It won't have a bend. your box width is 40.5" - wood thickness of each side(.75x2) = 39" > 36"

That is accounting for woofer displacement. The only thing not accounted for is any additional bracing you may add, but dowel rods don't have much volume so I wouldn't worry about it.

No problem, glad I could help.

Yes it would have to bend, but even at 34.25 it should bend.

Am I missing something Stefan?

but isnt it supposed to have 5 inches of width all the way through? with that at 36" id have 3.75 inches or so at the end of the port if it didnt bend.

what would port tuning be at if i didnt change the box at all?

i can go a half inch more without bending the port.

Edited October 7, 201212 yr by NickHall

Am I missing something Stefan?

He's doing a side port. The external width of the box is 40.5" - 0.75" - 0.75" = 39"

The port length would be 36". Why wouldn't 36" fit in 39"?