who wants to check my numbers?

[02parkave 5,000+ posts]

hey all- just need some #'s checked for me.... ok heres the deal, and what ive come up with- i need 14 cubes after displacements tuned to 32 hz...

heres what i have (internal dimensions)- 45"w x 40"d x 16"h.

port is a slot port measuring 40"w x 5"h x 16.25"d

subs displace . 4 cuft combined, i believe. does that look right to you guys? is my tuning off? also, if someone could tell me the depth for a 36hz tuning that would be great also!

thanks, guys

Click to read more...

 

[xluben 10+ year member]

you also need to account for port and driver displacement //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

you have 14ft^3 internal volume, but after displacement it's under 12ft^3

shouldn't the port be 38.5" x 5" if it's 0.75" mdf?

for those measurements i get:

11.72ft^3 @ 40Hz

//content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

keep trying //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

EDIT: where in MN are you? i'd love to come see this huge box when it's done //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[02parkave 5,000+ posts]

what am i doing wrong then? my math says

16*45*40=28800

28800/1728 (12*12*12)=16.67 (rounded off)

and- that is the internal port dimesion.... so

40*5*16.25=3250

3250/1728=1.88 (rounded again)

so thats 16.67-1.88-.40 = 14.39... am i wrong or... also- i am over by winona.. but i get to the cities often if you wanted to see it. its for 4 18's..... thanks for the help, and if i am doing something wrong, PLEASE tell me..

anymore help is greatly appriciated!

 

[Chevyaudio 5,000+ posts]

you arent accounting the for the wood...unless those box dimisions are internal...

I also got 40.533 hz

 

[02parkave 5,000+ posts]

yes- i am- in the original post i said- heres what i have (internal dimensions)- 45"w x 40"d x 16"h. how are you getting the 40 hz tuning? winisd that far off? what would be a 31-32 hz tuning then, and could someone explain to me about how to get the tuning correct?

 

[xluben 10+ year member]

oops, my bad.

i too those dimensions as external!

i also used winisd for the port calculation, so i think you're good now //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

you should also account for the piece of mdf for the port, but that's not gonna change much.

have any rendering of how the subs are going in the box?

seems like you're going to need a bend in the port //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

remember to measure length down the middle and add 1/2*width (to get the effective length.

 

[02parkave 5,000+ posts]

why would i bend the port- its gonna be subs up port back- port should go against the back wall, ports straight shot down the middle. thanks for all the help guys!