can someone explain how port velocity works

[BMS]

A really quick trick if your box isn't quite right is to invert your sub. what this will do is increase the net volume which will lower your tuning it will also cause the sub to put out more output at it's tuning but at the price decreasing the flatness of the responce range (it will make it more peaky).

[BMS]

A really quick trick if your box isn't quite right is to invert your sub. what this will do is increase the net volume which will lower your tuning it will also cause the sub to put out more output at it's tuning but at the price decreasing the flatness of the response range (it will make it more peaky).

[akuma4u]

A really quick trick if your box isn't quite right is to invert your sub. what this will do is increase the net volume which will lower your tuning it will also cause the sub to put out more output at it's tuning but at the price decreasing the flatness of the response range (it will make it more peaky).

i dont have enough space to do that .. i feel i tuned the box too low.. i was thinking of cutting a few inches of port in an attempt to increase the tuning frequency.. maybe that will give me the output im looking for in the band im interested in.. i also made the port width a tad bit too small.. no way to correct that unless i build a new box - not even sure if making it 1/4 of an inch wider will even have an audible effect ..

[BMS]

assuming you have 2.0 cub of net volume with that port your tuning is 33 hz. maybe there are other reasons you don't have a lot of output. net vloume is the total external volume minus the wood the subwoofer and the port displacement.

[BMS]

1/4 inch off of the 2.5 inch dimension would likely make a difference of the 12 dimension don't bother

[BMS]

so do you have 2 cubic feet. What is your wood thickness. do you have any leaks holes ect around the sub is gasketed.

[BMS]

if you would like to tune that high you should use a subsonic filter to prevent over excursion also typically 45-50 hz are spl tunes and not used on daily music setups but i have done it. Here is th math on the subsonic filter for a 12 db/octive crossover for 45 hz. Lets say you are tuned to 45 Hz:

- 45 Hz / 2 = 22.5 Hz (one octave lower)
- 22.5 Hz /2 = 11.25 Hz (half an octave lower)
So we take 45 - 11.25 = 33.75 Hz (rounded up to 34 Hz)

[BMS]

cut your port length down if you cut it to 10 inches instead of 32 you will gain .4 cubic feet of net volume bringing your tuning to 45 ish hz assuming that we started with a 2.0 cu foot box. Don't increase your port area you have enough.

[Krakin]

It's all about port area rule of thumb is 12-16 sq inches per cubic foot of net volume.

Absolutely, 100% not true.

[BMS]

well ok what i meant by its all about port area is that following the rule will ensure your velocity isn't so high that it makes excess port noise most of the time. How ever could you go over 16 sq inch... i suppose so under certain circumstances but we could talk all day how nothing is really true about audio equipment under all circumstances.