Port tuning problem with Torres

[sbelew]

Trying to learn and design a round port enclosure. I get the box volume right and the tuning frequency correct, but I am having a problem with hitting the 9" to 13" of port per foot rule. I either end up way low, like in the 5" to 6" range, or I end up with a crazy length of port that needs to make 90 degree turns. I've tired using 1 and 2 ports, different diameters and lengths. It just doesn;t seem to come out right. My enclosure is 2.6 gross tuned at 32Hz

Can anyone help?

[Joe X]

Better tell what sub(s) and what maximum dims you have. Aeros are easy to work with on big boxes and/or high tuning.

[deeje]

Generally when tuning low on a small enclosure and trying to get 13sq inches of port per foot the the length is going to have to be long.

[sbelew]

Enclosure is/will be 29.5"w X 13"h X 15.5"d 2.6 Cu ft which is what is recommended by Boston, Subs are 2 Boston Acoustics G110-4 I need to make an enclosure for these, but I am also using it as a learning experience. Using round ( I assume straight PVC ports)with two 3" ports I can ge the tuning down to where I think I want it, in the 31Hz range, but the port area per foot is down around 5 or 6. From what I understand, I need to be at 9" to 14" per foot.

[deeje]

Circular ports don't need to have as much and that is really the only way to get low tuning on a small box. On the right side of the calculator it tells you how much you need when you put a round port.

[Joe X]

Your problem is 2.6 cubes of for net internal volume, not external, here is a cutlist subs front/ports side:

Enclosure Specifications:

Fb = 32 Hz

Vb = 2.58 ft^3

External Height = 13 in

External Width = 35 in

External Depth = 15.5 in

Cut Sheet List:

* All Dimensions in Inches.

* Wood Thickness is 3/4 for all Parts.

External Enclosure Parts:

Front & Back = 35 x 13

Left & Right Sides = 14 x 11 1/2

Top & Bottom = 35 x 14

Port Quantity and Dimensions:

Number of Ports = 2

Pipe Port Diameter = 4

Pipe Port Length = 22 3/4

It could be done deeper and not as wide depending on your space

[sbelew]

So what determines the port diameter? Just whatever diameter, length and number of ports get me to the tuning number im trying for while staying within the 9" to 14" rule?

[Joe X]

So what determines the port diameter? Just whatever diameter, length and number of ports get me to the tuning number im trying for while staying within the 9" to 14" rule?

Basically whatever port or set of ports that you can fit and can reach the 9-13 rule, note that the other rule is that in this case both port ends need 4" of free arispace in front of them or you will loose the intended tuning.

[sbelew]

Yes, I had read that too, clearance on each end of port needs to be 1x the port diameter i believe was the way it was written. Joe, thank you so much for your time, and explaining this stuff to me. Not looking to go into the enclosure building business, just looking to increase my personal knowledge. Thanks again!

[Joe X]

No problem, anyways if you have the 35" you can just build the above if not you will have to exchange width with depth.. luck with your build.