Flared port sizes for 4KW?

[silenkiller 10+ year member]

I'm going to put two hdc3's in 8cuft/tuned to 35hz. I was thinking about using flared ports. For that amount of power, is there a minimum port diameter you guys recommend to avoid port noise?

I was thinking two 4 inch ports, 4 inches long.

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[oldschoolboomer 10+ year member]

what size subs?

 

[terra 5,000+ posts]

2 6"s or 4 4"s

 

[dappa5 10+ year member]

aeros are more efficient than slots so rule of thumb for slots is 12-16 in^2 per ft^3 and aeros 8-10in^2 per ft^3 I'd go around 10 sq in per cube which would be 80 in sq of area so bout 3 6's but two would still be close to acceptable limits @ 56.52 in sq

 

[silenkiller 10+ year member]

ic. two 15's for the guy who wanted to know.

weird. i guess the winisd calc is off a bit eh? lol

What I dont understand very well is why when i increase the diameter of the ports, that the length has to increase so much. For 3 six in ports, I'd need 19.94 inches on each of them. Seems kinda long?

http://www.psp-inc.com/psp-inc.com/cgi-bin/port_length_calculator.cgi

Unless it is saying thats the TOTAL length, divided by the 3 six inch ports.

 

[silenkiller 10+ year member]

.. and what confused me more, is that when you determine the volume of just a cylinder, its saying I only need like 1inch deep 6 inchers = 38 sq inches of vol per port.

Can someone elaborate on this a bit more, or at least point me in the right direction?