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View Full Version : I need some help with my next box.....



Grinder1989
03-12-2008, 10:04 PM
Here is what I have to work with.

48" long

23" tall

14" deep

Sub and port will be firing up.

Port area must be 70 square inches

I'm looking around 5 cubic feet after sub displacement but I have no idea what the displacement would be so we'll say the equivalent of an MT.

I do not have any specs on the sub but I'd like it tuned anywhere between 28hz-35hz.

I have tried to design this myself but I'm not sure what to do about port area and all that. Oh and the sub is the 15" Nightshade Prototype. Thanks for the help. :)

bonesninja
03-12-2008, 10:07 PM
70 sq inches of port with 5 cubes net =port length of around 31.5 to get 30 htz

Grinder1989
03-12-2008, 10:09 PM
70 sq inches of port with 5 cubes net =port length of around 31.5 to get 30 htz

But doesn't that increase the port area? Is it bad if there is too much port area?

bonesninja
03-12-2008, 10:20 PM
the port area is measured at the opening, assuming that the port is the same width/height throughout the port. the port area remains the same regardless of the length, you just go longer or shorter to get the tuning you want

Grinder1989
03-12-2008, 10:20 PM
I meant square port volume. Sorry :)

bonesninja
03-12-2008, 10:22 PM
the volume, measured in cubic units, occupied by the port will go up or down depending on the length but the port area is constant.

Grinder1989
03-12-2008, 10:23 PM
But does the port volume have an impact on the sound? I know the tuning can be changed with it but I wasn't sure if port volume affect anything else.

bonesninja
03-12-2008, 10:33 PM
But does the port volume have an impact on the sound? I know the tuning can be changed with it but I wasn't sure if port volume affect anything else.

The port AREA can have dramatic effects on the sound, too little area and you can have lots of port noise = bad. Also length can have equally dramatic effects due to the tuning differences.

The best advice i can give you is to have one of the more reputable box designers model you a box based on your dimensions, port and space requirements. A properly designed box can be priceless, the best built box in the world can be crap if the design is flawed

Grinder1989
03-12-2008, 10:37 PM
The port AREA can have dramatic effects on the sound, too little area and you can have lots of port noise = bad. Also length can have equally dramatic effects due to the tuning differences.

The best advice i can give you is to have one of the more reputable box designers model you a box based on your dimensions, port and space requirements. A properly designed box can be priceless, the best built box in the world can be crap if the design is flawed

Yea I was looking for that but, my specs are as follows on the box I just designed:

square port area = 86
square port volume = 3526
square port volume displaced = 3551.125
Box volume = 5.177 cubic feet
Its tuned @ ~30

bonesninja
03-12-2008, 10:44 PM
so yeah it looks like 5.177 cubes after port before sub, which if you want 5 cubes net, you're fine. Port looks fine ...its taking up 2 cubes by itself.

Grinder1989
03-12-2008, 10:45 PM
so yeah it looks like 5.177 cubes after port before sub, which if you want 5 cubes net, you're fine. Port looks fine ...its taking up 2 cubes by itself.

So do you think that would be a decent box for that sub?

bonesninja
03-12-2008, 10:56 PM
not familiar with the sub at all, but the box looks nice and loud, should hit the lows pretty good. Do you know what the Fs is of the nightshade?

Grinder1989
03-12-2008, 10:59 PM
not familiar with the sub at all, but the box looks nice and loud, should hit the lows pretty good. Do you know what the Fs is of the nightshade?

Not a clue. I wish I could find the conversation I had with Jake about it. I asked him the specs and he said "loud" :laugh:. But he never tested it I guess.

Grinder1989
03-13-2008, 09:04 AM
Bump, thanks for the help Bones. :)

Grinder1989
03-14-2008, 09:28 AM
Up. OK so I have the plans and I'm going to pick up the wood in a week or two. I have an assload of drywall screws so the only other thing is the glue. I've used liquid nails in the past and never had any problems but I'm sure there are better things out there. What glue do you guys use?

Grinder1989
03-16-2008, 01:09 AM
Bump.

amatt85
03-16-2008, 01:17 AM
ditch the liquid nails and use some titebond (either kind will work...i usually get titebond II or III)...and dont go crazy with screws...they are useless anyways once the glue dries.

Grinder1989
03-16-2008, 01:21 AM
ditch the liquid nails and use some titebond (either kind will work...i usually get titebond II or III)...and dont go crazy with screws...they are useless anyways once the glue dries.

I heard its one screw every 6 inches. I'll probably get titebond.