2 bl 18's in tahoe

[07_ZX10 4]

Buddy of mine has 2 bl 18's ran off 1 sundown 2500d, he has them in slot port now in about 12.5 cubes gross. They sound decent, but dont really have the lows, and its tuned to 32hz. He wants new box with 4 6" aeros's in about 16 cubes net tuned to 32hz. How does this sound for size? I ran 2 bl 18's about 2 years ago off 2 sundown 1500d's in about 18 cubes net with slot port and they pounded the lows, and sounded perfect. I just havent done any builds with aero ports.

[XxedgarxX 2]

thats about the same setups i had on my bl's too. one box of 12.5cf with slot port and the lows were not that strong lol then i did 19 cubes with 2 8" ports and it killed everything lol

[Freshh 11]

I've heard that to make the BL's shine you need LOTS of port area.

That's just reading off of the forums. So take it with a grain of salt I suppose.

[trod2902 26]

I only have a 12" Bl, but when i built the box before my current one, i had 30 in of port area which i had calculated to be the minimum and it sounded good and played low. Then i built my current box but used 55.5 inches of port area and holy shit its much louder and plays everything better, so i definitely agree with the post above on port. A larger box should allow it to play lower as well.

[ricksi30 923]

Build a bigger box for sure but 4 6" aeros is nowhere near enough port are for the two 18's.

[S.DeYoung 967]

Build a bigger box for sure but 4 6" aeros is nowhere near enough port are for the two 18's.

And why not? Have you calculated port area and speed? I found that you need a minimum of 15" diameter with aero ports @ 32hz. So four 6" is plenty.

[ricksi30 923]

Build a bigger box for sure but 4 6" aeros is nowhere near enough port are for the two 18's.

And why not? Have you calculated port area and speed? I found that you need a minimum of 15" diameter with aero ports @ 32hz. So four 6" is plenty.

Ummm one 15 is more port area than four 6's???

Edited September 5, 2011 by ricksi30

[trod2902 26]

4 6" aeroports are equivalent to about 1 12" in area, but there are additional "frictional losses" due to using multiple ports as well

Edited September 5, 2011 by trod2902

[ricksi30 923]

4 6" aeroports are equivalent to about 1 12" in area, but there are additional "frictional losses" due to using multiple ports as well

Yes that's my point SDeYoung says minimum of 15 and then says 4 6's is plenty which is not true.

[S.DeYoung 967]

15" total diameter. Not one 15" port. Four 6" ports will work well.

[ricksi30 923]

15" total diameter. Not one 15" port. Four 6" ports will work well.

So 15 one inch ports would be okay?

[S.DeYoung 967]

15" of diameter is the minimum I would recommend for the box. But yes one 15" port would work.

[ricksi30 923]

15" of diameter is the minimum I would recommend for the box. But yes one 15" port would work.

Your calculation of 15" minimum is correct,(If you use one 15 inch port) however one 15 is ~176^2" and four 6 inch ports are ~113^2" You do understand that two 6 inch ports is not the same as one 12 inch port right?

Edited September 5, 2011 by ricksi30

[S.DeYoung 967]

Yes i do understand that. With aeroports you do not need 176 square inches of port area. That is the whole idea of them. They reduce port noise with less port area.

[stovebolt6 3]

Yes i do understand that. With aeroports you do not need 176 square inches of port area. That is the whole idea of them. They reduce port noise with less port area.

yes they are known to reduce port noise, but they do not defeat the law of physics.

there is a small reduction in friction, through the reduction of turbulence, but it is really small, i use aero's in every ported box i build.

multiple smaller ports will not perform as well as one single larger aero, even if you have the exact same amount of area.

setups with multiple ports create more friction, and in extreme cases can cause tuning to drastically change as output increases.

if you can, always go for the least amount of ports as possible by increasing the diameter.

just a suggestion.