can someone explain how port velocity works

[akuma4u]

can someone explain how port velocity works and how to calculate it and how it relates to slotted/vented enclosures. I believe its required to make sure you dont get port noise..

[BMS]

It's all about port area rule of thumb is 12-16 sq inches per cubic foot of net volume. You want to avoid noise 3 things 1. make sure you have enough port area 2. if your port is a 4'' diameter the end must be 4'' away from the back of your box and the other end out of the box must be 4'' away from any obstructions, or your shortest side on a rectangular port is how far it has to be away, if it is not round. 3. make sure your port is the same size all the way through (no bottlenecks).

[akuma4u]

2. if your port is a 4'' diameter the end must be 4'' away from the back of your box and the other end out of the box must be 4'' away from any obstructions, or your shortest side on a rectangular port is how far it has to be away, if it is not round.

trying to wrap my head around this.. a diagram would sure help if u can find one explaining what u just said...

im trying to gain more output... i want to increase the port area a bit more than what the manufacturer recommends so i can move more air but not sure if thats a good idea?

[BMS]

I increased the port area from manufacturer specs on a pair of 6.5 subs and had amazing success. send me a link to the manual and what sub you will use also the amp might help too.

[akuma4u]

I increased the port area from manufacturer specs on a pair of 6.5 subs and had amazing success. send me a link to the manual and what sub you will use also the amp might help too.

http://sundownaudio.com/index.php/subwoofers/z-v-3-series

its a 12 inch , 2000rms , they recommend 32 sq inches im thinking of going to 34-38 range and making port width to 3 inches or 3.5 inches from 2.5 on previous box that left me wanting more output..

[BMS]

port area needed is determined by your net volume not the subwoofer remember increasing port area changes your tuning to be higher so to keep the same tuning the port needs to become longer and if the port becomes bigger it takes up more of the net volume also changing the tuning frequency and the type of response you will get.

[BMS]

so you will through 2000 wrms ok can i ask the amp just to be sure it does rated power.

[akuma4u]

so you will through 2000 wrms ok can i ask the amp just to be sure it does rated power.

it does rated it will be either a crescendo bc2000 or a hifonics brx2400 that does 2000rms at 14v

its a sundown zv3 12 inch sub

i had a box tuned to 35hz wit a slot port 2.5 width but it was tuned a little too low and lacked output in the range i was looking for which is 40-50hz.. so i wanted to tune it a little higher and also increase the port area and width a bit to increase output and move more air...

[BMS]

oh i see where you got the recommended port area from 32 sq feet for a 2.0 cub is at the top end of the rule of thumb i wouldn't add more port area what are the dimensions of your current port. if you add to much port area there is not as much restriction on lows and over excursion becomes more of a problem and the responce becomes less "accurate"

[akuma4u]

oh i see where you got the recommended port area from 32 sq feet for a 2.0 cub is at the top end of the rule of thumb i wouldn't add more port area what are the dimensions of your current port. if you add to much port area there is not as much restriction on lows and over excursion becomes more of a problem and the responce becomes less "accurate"

12 x 2.5 and 32 long