PDA

View Full Version : does this all make sence?



splescort
09-25-2011, 10:32 PM
hdc315 copper
28" w
21" h
20" d
port 19.5" x 4" = 78sqinch
total port length 22"
tuned to 39.78 hz
cuft 4.53 before sub displacement
cut list
top 28x20
bottom 28x20
left side 19.25x18.5
right side 19.5x18.5
back 28x19.5
front 23.35x19.5
port 14.5x19.5

gonna power with 1500rms
going to do sub up and port back

Kangaroux
09-25-2011, 10:36 PM
You got a diagram we can go off of? Maybe it's just me cause I'm lazy but that's gonna take a while to check lol

splescort
09-25-2011, 10:47 PM
cant say i do, its all on the back of a napkin kinda drawing

hispls
09-25-2011, 11:03 PM
hdc315 copper
28" w
21" h
20" d
port 19.5" x 4" = 78sqinch
total port length 22"
tuned to 39.78 hz
cuft 4.53 before sub displacement
cut list
top 28x20
bottom 28x20
left side 19.25x18.5
right side 19.5x18.5
back 28x19.5
front 23.35x19.5
port 14.5x19.5

gonna power with 1500rms
going to do sub up and port back

Seems like a lot of port area. If those are the outer dimensions of the box you'll be down to more like 3 cube net with sub/wood/bracing/port displacement.

15 square inches of port per cube of net volume 18" long should tune to around 40hz and is pretty much a win for this type of sub (or just use any of the cookie cutter DD boxes)

splescort
09-25-2011, 11:36 PM
3 cuft????
makes no sense
5.53cuft is gross for 28x21x20 outer out of 3/4 wood
then my sub displacement is 0.23 (as per DJ from AQ)
and port displacement is 0.99
so 5.53 gross - sub (0.23_ - port(0.99) = 4.31cuft
bracing i am gonna use threaded rod so at max maybe another 0.10cuft
so total net 4.21cuft.

hispls
09-25-2011, 11:52 PM
3 cuft????
makes no sense
5.53cuft is gross for 28x21x20 outer out of 3/4 wood
then my sub displacement is 0.23 (as per DJ from AQ)
and port displacement is 0.99
so 5.53 gross - sub (0.23_ - port(0.99) = 4.31cuft
bracing i am gonna use threaded rod so at max maybe another 0.10cuft
so total net 4.21cuft.

Indeed. Just threw it into my spreadsheet and it looks good. 10" sono tube would make a find round port for that as well.... same length

splescort
09-26-2011, 12:01 AM
whats better slot port or sono tube and why?

hispls
09-26-2011, 12:12 AM
Round port is somewhat supperior accoustically IMO. Also with sono tube it's really easy to make it a bit longer to try lower tuning then cut it down an inch at a time to experiment with higher tuning, or just carve it out and replace with a longer one if you want to go lower again. A bit less displacement since the walls are thinner, and only 8$ for a 4 footer at home depot.

I find it's simple, functional, and allows a lot of flexibility as far as modifying tuning quickly and without major surgery.