First Box Design 2 DD 1008A's Ext Cab Truck

[lilmaniac2]

1.8 cubes internal after displacement
tuned to 34hz

Square Prism Box Parts
1 Top, 1 Bottom: 22.5 (c) x 15 (b) in
0.75 (thick) in
1 Front, 1 Back: 13.5 (a) x 13.5 (d) in
0.75 (thick) in
2 Sides: 13.5 (a) x 22.5 (c) x 0.75 (thick) in

Vent Parts
1 Duct: 4.25 (e), 4 (g) x 13 (h) in

[lilmaniac2]

and a graph from bbp6... not really that usefull, but i had it so here it is

[PowerNaudio]

looks good bro.

[lilmaniac2]

Thanks man, DD's just dont seem to model well at all...

[PowerNaudio]

it would be great if we could have an infinite access to what ever speaker we are design an enclosure for. that way we can run the test our selfs to determine the speakers t/s parameters, instead of having to depend on the manufaturers provided specs. " which are some times off" which change once the speaker has broken in. lol

what's the port air velocity on that 4" port for that particular system?

[lilmaniac2]

[PowerNaudio]

The generally accepted rule of thumb for preventing turbulence and port compression is to design for a max velocity of 5% of the speed of sound, or about 17 meters per second (~55 feet/sec).
by looking at the graph you provided it may seem like there will be some port noise below 45Hz @500wrms of power.

if the port was flared on both ends it could be posible to get away with that port size.

here is the equation for none flared port air velocity.
Maximum Velocity = [3570 + ( port diameter ^ 2 )] /1785 * area ratio
Velocity is in metres per second. Port diameter and flare radius are in millimeters

here is the link providing that info.
http://www.subwoofer-builder.com/fla...-equations.htm

[IonSQL]

Good info....

[lilmaniac2]

Yes i know that VV is supposed to be kept below a certain level, but the client gave me specs and said he would only use a single 4" aero... Already had one, and didnt want a slot port... I just do what the customer wants

[IonSQL]

I'd imagine it'll be OK if you're using an Aero....

Box looks good bro :clap2: