Is xmax directly related to port area?

[helotaxi 5,000+ posts]

More port area means lower port velocity which means lower potential for port noise. Port noise indicates a loss in SPL if that's what you're after and it sounds annoying if you're after SQ. There is no difference in how it actually sounds and you either have enough port area or you don't. There are various ranges of not enough from the point where the port is so small that the box behaves like a leaky sealed box to sound correct but having a lot of port noise at high volume. If you are running lower power, you can have less port area without problems. You can have too much port area as well. At that point the port is not able to load the sub and the sub behaves as if it were in free air and there is next to no output. There are trick to allow you to run slightly smaller ports without noise, such as flaring the ends, as well.

 

[MyFartsStink 10+ year member]

More port area means lower port velocity which means lower potential for port noise. Port noise indicates a loss in SPL if that's what you're after and it sounds annoying if you're after SQ. There is no difference in how it actually sounds and you either have enough port area or you don't. There are various ranges of not enough from the point where the port is so small that the box behaves like a leaky sealed box to sound correct but having a lot of port noise at high volume. If you are running lower power, you can have less port area without problems. You can have too much port area as well. At that point the port is not able to load the sub and the sub behaves as if it were in free air and there is next to no output. There are trick to allow you to run slightly smaller ports without noise, such as flaring the ends, as well.

please explain what flaring the ends mean.

 

[BrianChia 10+ year member]

please explain what flaring the ends mean.

 

[IDSkoT 5,000+ posts]

Flaring is when it's rounded off at the end of the port. Like you can see on that Aeroport, the end is flared out at a nice soft angle so the wind doesn't "whistle" off the edges. Someone explained it to me like a whistle.

 

[MyFartsStink 10+ year member]

Flaring is when it's rounded off at the end of the port. Like you can see on that Aeroport, the end is flared out at a nice soft angle so the wind doesn't "whistle" off the edges. Someone explained it to me like a whistle.

Now would this at all take away from the port length though? would I have to add port length to it?

 

[helotaxi 5,000+ posts]

The flare actually difuses the air coming out the port which reduces the velocity at the port's ends. There are equations out there to account for the flare when figuring port length. Devil Driver has them and should also have a link to an Excel spreadsheet that I made to calculate it.