ATTN: Box Designers. Please check my work

[rickmandick]

Box Length 30

Box Height 19

Box Depth 19

LxWxH=10,830

10,830 x .77 = 8339.1 Gross Internal

8339.1 x .82 = 638.062

638.062 / 1728 = 3.96 Net Internal

Now if i want roughly 65 inches of square port, a port width of 3.75 and a tuning of roughly 35hz, my cut sheet looks like this. Please tell me how far Im off. I havent done this in 8 years, but according to my math, Im right where I need to be. This if for port and sub front facing, with an L shaped port.

Top: 30 x 19

Bottom: 30 x 19

Back: 28.5 x 17.5

Front 25.5 x 17.5

Right: 19 x 17.5

Left 19 x 17.5

Side Port: 13.75 x 17.5

Back Wall Port 3.75 x 17.5

Like I said before, shooting for 35-36 hz

Click to read more...

 

[rickmandick]

Anyone?

 

[anger 10+ year member]

Box Length 30Box Height 19

Box Depth 19

LxWxH=10,830

10,830 x .77 = 8339.1 Gross Internal

8339.1 x .82 = 638.062

638.062 / 1728 = 3.96 Net Internal

Now if i want roughly 65 inches of square port, a port width of 3.75 and a tuning of roughly 35hz, my cut sheet looks like this. Please tell me how far Im off. I havent done this in 8 years, but according to my math, Im right where I need to be. This if for port and sub front facing, with an L shaped port.

Top: 30 x 19

Bottom: 30 x 19

Back: 28.5 x 17.5

Front 25.5 x 17.5

Right: 19 x 17.5

Left 19 x 17.5

Side Port: 13.75 x 17.5

Back Wall Port 3.75 x 17.5

Like I said before, shooting for 35-36 hz

Looks close enough to me. I'm no designer, but have a few enclosures under my belt. I'm showing 4.175ft^ net. 35-36hz...assuming you're using 3/4" material.

 

[rickmandick]

Looks close enough to me. I'm no designer, but have a few enclosures under my belt. I'm showing 4.175ft^ net. 35-36hz...assuming you're using 3/4" material.

Yes Im using DD's calculations and and old trusty calculator. Ive used the specs before to build box's for my DD's before I quit. 7-8 years away and you get rusty. Before anyone asks about my math, I'll show you the basis for it.

.77 is the number recommended by DD for enclosures under 5 cubes to get gross internal. It really should be .75, but that falls under the 10%.

.82 is the number recommended by DD to include subwoofer, bracing and port displacement.

These numbers do not appear "magic" at all. DD came up with them after running calculations for enclosure's under 5 cubes all while taking into account the average sub, bracing and port displacement.

At this net size DD recommends, 64 sq of port and 19 inches in length for a tuning for 35-40hz.

I've used Torres and everything else the past few days. Not much help with DD's limited available T/s numbers and none seem to work for a L port.

 

[anger 10+ year member]

Yes Im using DD's calculations and and old trusty calculator. Ive used the specs before to build box's for my DD's before I quit. 7-8 years away and you get rusty. Before anyone asks about my math, I'll show you the basis for it.
.77 is the number recommended by DD for enclosures under 5 cubes to get gross internal. It really should be .75, but that falls under the 10%.

.82 is the number recommended by DD to include subwoofer, bracing and port displacement.

These numbers do not appear "magic" at all. DD came up with them after running calculations for enclosure's under 5 cubes all while taking into account the average sub, bracing and port displacement.

At this net size DD recommends, 64 sq of port and 19 inches in length for a tuning for 35-40hz.

I've used Torres and everything else the past few days. Not much help with DD's limited available T/s numbers and none seem to work for a L port.

Ya, I think you're good. I didn't account for bracing or sub displacement. I say build it! or wait for someone with more knowledge to chime in.

I ran your numbers through http://reaudio.com/box.php

I hear it's not the best, but it's worked well for me.