Need Help With My Port

[sml238 10+ year member]

Ok well I'm building a box for my hdc315. I already have my wood cut except for the port.

Box dimensions

H = 16.5"

W = 43"

D = 16.5" (This is the top where the sub and the port will be. It's double baffled so it will be 17.25" with the second baffle)

I need the box tuned to 36hz with around 65sq" of port area. Could someone tell me the dimensions I need my port to be and the final volume with my port displaced.

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[DonH 5,000+ posts]

so what you would want is a port that is 15" high by 4" wide. thats 60 square inches of port which is more than enough! for your port piece its simple tou will only need on piece that is 11X15! thats all! there you go. 36 hz 60 square inches of port!

port displaces 1118.25 in^3

here is a pic of what u need to do.

if you really need 65 square inches here is a port that is L shaped and is 67.5 inches at 36hz

port displaces 1614.75

edit: just noticed that u said double baffled! HAHA well all you do is add .75 inched to the longest piece of the port.

 

[germandark 10+ year member]

x2 on that response! I agree, 60in^ should be plenty.

 

[sml238 10+ year member]

yeah but what about the double baffle? its really 1.5" longer than that because my port is on the side with the double baffle.

and what would be the volume of the box with the port displaced. and i would need a 45 angle piece in the corner still right?

 

[DonH 5,000+ posts]

i got your pm brbo i had to leave for a while but listen its only .75 longer!!! you place the piece on the inside of the front baffle! so there fore the front baffles thickness is part of the overall port length! so with thoze drawing's they have one baffle when you add the second baffle that adds another.75 to the length of the port which changes the tunings unless you compensate which means adding .75 to the length. also since your doing the couble baffle the side with the port will need to be .75 longer to make it flush with the double baffle and keep the port tunning the same.

hope that explains it.

 

[sml238 10+ year member]

i got your pm brbo i had to leave for a while but listen its only .75 longer!!! you place the piece on the inside of the front baffle! so there fore the front baffles thickness is part of the overall port length! so with thoze drawing's they have one baffle when you add the second baffle that adds another.75 to the length of the port which changes the tunings unless you compensate which means adding .75 to the length. also since your doing the couble baffle the side with the port will need to be .75 longer to make it flush with the double baffle and keep the port tunning the same.
hope that explains it.

well ur saying the piece i need to put in my box will be 11x15. if the piece is 11 i have 4" port and 4" from the back of the box to the port. but really my port is going to be 1.5" longer than 11" wouldnt that change the tuning? look here is a model of my box so i can show u what im talking about.

see how the baffle makes it 1.5" longer? i dont have it so the first baffle is flush with the sides.

 

[DonH 5,000+ posts]

well ur saying the piece i need to put in my box will be 11x15. if the piece is 11 i have 4" port and 4" from the back of the box to the port. but really my port is going to be 1.5" longer than 11" wouldnt that change the tuning? look here is a model of my box so i can show u what im talking about.
see how the baffle makes it 1.5" longer? i dont have it so the first baffle is flush with the sides.

sry bro! you would subtract .75 from 11! i reall sry man subtract .75 to compensate for the added .75 by the second baffle!

 

[sml238 10+ year member]

sry bro! you would subtract .75 from 11! i reall sry man subtract .75 to compensate for the added .75 by the second baffle!

but wouldnt i subtract 1.5 cuz its 2 baffles? look at my drawing the edge of the port doesnt go flush with the first baffle it goes under it.

and doesnt the space between the end of the port and the back of the box have to be the same as the width of the port?

 

[DonH 5,000+ posts]

but wouldnt i subtract 1.5 cuz its 2 baffles? look at my drawing the edge of the port doesnt go flush with the first baffle it goes under it.
and doesnt the space between the end of the port and the back of the box have to be the same as the width of the port?

ight check it out yess it need to be 4 inches. Now why are you extending your sub baffles that far? you dont need to! you wont have to cut square hole into each piece! ima design something up right quick ight.

 

[DonH 5,000+ posts]

look you need an overall port length of 11.75 inches.