SPL: more Port Area or lower Port Mach?????

[imhungnurnot 9]

I am currently designing a box for a DD9512g which will be on a SAZ 2500D. I wanna tune to 36-37 Hz with about 2.5-2.6 net volume.

My question is: What has greater potential increase of SPL. A lower port mach or more port area?

Thanks!

[Kanaworm$ 292]

To little port area can result in "huffing" or port noise. Port area is your friend!

[///M5 2,833]

Within reason. Modeling is your friend.

[a1161979 3]

It will depend on how the port loads, its hard to model that. In SPL its all about testing different ports to see what works best, as a general rule we start with area before we tune length in a burp box.

For a 2.5 cube music box id try 40 square and go from there

[antonmiller 8]

test, with spl every little thing will change somthing, whether its your impediance rise or your score alone. every little thing changes somthing. for my car, small port was better, now for yours, huge port might be better (and by small port i mean 5 sq per cube!) So there will never be a straight awnser for this, its somthing you need to find on your own, with testing.

[Adrian_D 520]

From my testing I have noticed that an increase in port area will show in score at high power.

For instance...with 1000w, going from 8 inch port to 10 inch port showed no increase. At full power, ~3500w, the bigger port showed a healthy gain.

This was in my install, with one 12 inch subwoofer.

[Duran 387]

Vance Dickason demonstrated that larger port area results in better port linearity, which equates to deebeez

[aimone 4]

ur using a dd sub whats dd's philosophy on ports?

"You need more port area for a clean sounding, high output system. The DD port formula is this: 16 sqin of port area per cubic foot of box volume. The port should be 16 inches long. Remember, the port is tuned to the box volume, not the sub(s).

This formula was derived from 1000s of hours of in-car testing and 1000s of installs. It works. It takes into account the need for increasing port area for increasing cone area. When combined with our DD subwoofer box requirements, you'll end up with the perfect match."

also

"The use of a larger than normal port will allow the user to find the cars peak frequency for greatest SPL"

http://www.ddaudio.com/caraudio/enclosureInfo/portInfo.htm

seeing as i live in the town where dd is based i've seen a few dd installs and even on simple installs the bigger the port the more it amazed me