How do aero ports work for enclosures?

[N8d513]

Hello all! I am by no means new to car audio but I am new to the aspects of ported enclosures. I have always went sealed as I was all about the sq but recently I have heard a few friends systems with ported enclosures and wow, not as accurate but extremely loud. My question is exactly how do aero ports tune the frequency of the box? Also how does one tune their subsonic filter when an enclosure is tuned to for example 30hz? Thanks for the help guys!

[bbeljefe]

Welcome to the forum. I can't speak to the ported enclosures you've heard but a properly designed and built ported box has better sound quality and low end extension than sealed... every time. That's why when you look in the winners circle at SQ competitions, you'll see ported boxes far more often than sealed.

That said, aero ports tune the box the exact same way any other vent tunes a box. Where they excel is in reducing vent noise and allowing less port area. Tuning is accomplished through mathematics and put simply, longer vents tune the box lower and larger vents have to be longer in order to tune at the same frequency as smaller vents. Vent area is dependant on xmax, tuning frequency and box volume, with the latter being the least important consideration in most applications.

As for infrasonic filters, they should be set at 5-10Hz below tuning and their function is to prevent unloading below the tuning frequency.

[poorfish88]

Torres Box Tuning program can be downloaded on this site. It's pretty much on point, and it's free.

[n8skow]

Box volume is actually not part of the equation for calculating necessary port area.

It comes down to the acoustic power of the woofer and the tuning frequency (which 'is' a fuction of box volume - but dosen't change port velocity). The formula for port velocity is:

(13.7 * SQRT(W)) / Fb x R squared

where W = acoustic power of woofer

Fb = tuning

R = radius of port

I would also argue Infinite Baffle is the best sq alignment - but kinda rare in usage these days...

Welcome to the forum. I can't speak to the ported enclosures you've heard but a properly designed and built ported box has better sound quality and low end extension than sealed... every time. That's why when you look in the winners circle at SQ competitions, you'll see ported boxes far more often than sealed.

That said, aero ports tune the box the exact same way any other vent tunes a box. Where they excel is in reducing vent noise and allowing less port area. Tuning is accomplished through mathematics and put simply, longer vents tune the box lower and larger vents have to be longer in order to tune at the same frequency as smaller vents. Vent area is dependant on xmax, tuning frequency and box volume, with the latter being the least important consideration in most applications.

As for infrasonic filters, they should be set at 5-10Hz below tuning and their function is to prevent unloading below the tuning frequency.