Polyfill in Ported Box Experience

[Parker Smith]

I've read and learned from this forum for a long time just never posted anything as I feel like all the appropriate info is given by the fellow users of this board.

First of all, my setup is an Alpine Type R 10D4 (newest gen) powered by a Rockford Fosgate Prime 1200D in a rear console slot ported box tuned to 34 Hz.

Having a single 10 that lacks major excursion among other factors didn't allow me to really hit anything below about 40 Hz or so plus I was getting port noise on the higher end of the spectrum so I had the box lined with polyfill. By doing this (and this is just my own personal experience), the bass sounds a whole lot "fuller" as well as a lot cleaner. And now I am able to hit notes closer to 30 Hz at the expense of a little less top end punch. It also virtually eliminated the port noise I was experiencing.

Cliff notes: Adding polyfill really aided to the SQ of my system as well as giving it a more wholesome "boomy" sound without taking away any of the punchiness 10's are known for.

[Guest]

your port noise and frequency bandwidth issues are caused by the port being way too small

[Guest]

there is no such thing as 10s having more punch or whatever than bigger woofers. or bigger woofers being more sloppy or boomy than smaller woofers. it's a myth

[Omega5002]

Too small of a port can cause what's call Port Compression

Here's a quote from Subwoofer-builder.com

"The reason a ported speaker works is because the air in the port causes a 180 degree phase shift in the air behind the driver. When the air comes out of the port, at least at the tuning frequency, it is in-phase with the front of the driver, giving a boost to the output.

As air in the core of the port becomes turbulent, this phase shift decreases, thus reducing the in-phase contribution made by the port. The total output of the box no longer rises at the same rate as input power is increased, and the port is said to be compressing

Eventually the port acts as a mere hole in the box, short circuiting the acoustic output of the driver and allowing excursion to become uncontrolled."

You need to make sure you have proper port velocity so the port can function correctly to be musical

[Parker Smith]

Thanks for the replies guys.

there is no such thing as 10s having more punch or whatever than bigger woofers. or bigger woofers being more sloppy or boomy than smaller woofers. it's a myth

Based on my personal experiences, the larger the cone (to an extent), the harder time it has keeping up with quicker, repeated bass notes. However that could be due to the box I suppose.

Too small of a port can cause what's call Port Compression

Here's a quote from Subwoofer-builder.com

"The reason a ported speaker works is because the air in the port causes a 180 degree phase shift in the air behind the driver. When the air comes out of the port, at least at the tuning frequency, it is in-phase with the front of the driver, giving a boost to the output.

As air in the core of the port becomes turbulent, this phase shift decreases, thus reducing the in-phase contribution made by the port. The total output of the box no longer rises at the same rate as input power is increased, and the port is said to be compressing

Eventually the port acts as a mere hole in the box, short circuiting the acoustic output of the driver and allowing excursion to become uncontrolled."

You need to make sure you have proper port velocity so the port can function correctly to be musical

Thanks for the info. Yes I know my port isn't necessarily ideal in size but I literally have the worst vehicle possible as far as room for subs. That is unless I take out my back seat and do a wall or something lol. But by adding the pollyfill, it seemed to help offset the fact that the port is a little too small and did eliminate the port compression I was initially having.

[Krakin]

I drive a single cab truck, think you got it bad?

[Omega5002]

Thanks for the replies guys.

there is no such thing as 10s having more punch or whatever than bigger woofers. or bigger woofers being more sloppy or boomy than smaller woofers. it's a myth

Based on my personal experiences, the larger the cone (to an extent), the harder time it has keeping up with quicker, repeated bass notes. However that could be due to the box I suppose.

It's always the box, I've heard punchy 18' setups and sloppy 10' setups, it doesn't matter how big the woofer is, you need to accomidate the correct box for it.

[Parker Smith]

I drive a single cab truck, think you got it bad?

Haha I can guarantee you have more space than me without me taking out my backseat lol

[Guest]

"slow"

box dictates how the woofer plays. shitty box, shitty sound. simple as that.

edit:

thats me getting a demo. every 12, 15, 18" woofer setup i've heard thats in a proper enclosure sounds perfectly fine.