Confused on this

[ace_800 5,000+ posts]

Ok what is the point of having 2 round ports in one enclosure. For instance mine has 2 3" ports which are the same length. Why run 2 instead of one if it just doubles your port displacement? Does it help anything?

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[OmegaBunny 10+ year member]

Adds port area. Not sure exactly but You want to try to keep port area at something like 14-20 in ^ 2 for each cubic ft.

 

[ahole-ic]

Adds port area. Not sure exactly but You want to try to keep port area at something like 14-20 in ^ 2 for each cubic ft.

For a slot. It's significantly less for an aero.

 

[OmegaBunny 10+ year member]

I wasn't sure about aeros and slots, I just know that you are supposed to plan on a certain amount or port area per cubic foot. Not even sure what the benefits are. Is it to reduce the port noise?

 

[ahole-ic]

I wasn't sure about aeros and slots, I just know that you are supposed to plan on a certain amount or port area per cubic foot. Not even sure what the benefits are. Is it to reduce the port noise?

No, a port is like a free woofer. So it's basically to increase cone area.

 

[OmegaBunny 10+ year member]

LOL //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[bubbagumper6 5,000+ posts]

I wasn't sure about aeros and slots, I just know that you are supposed to plan on a certain amount or port area per cubic foot. Not even sure what the benefits are. Is it to reduce the port noise?

If your port is too small you will get port noise, yes.

 

[ahole-ic]

LOL //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

What was confusing?

 

[OmegaBunny 10+ year member]

how is the port like a free woofer? I know it helps to keeps the cone under control...

 

[ahole-ic]

how is the port like a free woofer? I know it helps to keeps the cone under control...

Have you ever heard of a passive radiator? The port is a mass of air. Notice the word "mass". Since air's mass is known for a given volume, we can control it based on it's area and length, coupled with the mass inside the box. This is how we tune it... just like a passive radiator. The air moves in and out of the port transmitting a sound wave through the air just like.... yep that's right... a woofer.

 

[ahole-ic]

Also I should state that I was not intending to sound like a jackass. I was trying to be informative but after re-reading it I sounded like a douche. My bad.

 

[OmegaBunny 10+ year member]

Ahh okay I see. So adding 2 3" aero ports is like adding 2 3" woofers because it is moving air. It's just not as audible as the air the woofer is moving, correct?

I always thought it was used to control the motor force inside the box to allow the woofer to only move so far.

 

---------- Post added at 01:59 PM ---------- Previous post was at 01:58 PM ----------

 

Also I should state that I was not intending to sound like a jackass. I was trying to be informative but after re-reading it I sounded like a douche. My bad.

LOL No problem

 

[ahole-ic]

Ahh okay I see. So adding 2 3" aero ports is like adding 2 3" woofers because it is moving air. It's just not as audible as the air the woofer is moving, correct?
I always thought it was used to control the motor force inside the box to allow the woofer to only move so far.

 

---------- Post added at 01:59 PM ---------- Previous post was at 01:58 PM ----------

 

LOL No problem

Well the port is actually incredibly efficient at its resonant freq. So a port and a woofer of the same area, if you were to measure the spl in front of the cone and in front of the port, the port would almost always be louder at its resonant freq. At all other frequencies however, the port becomes less and less efficient the farther from resonant it gets. Above tuning it falls off slower. Below tuning it falls off very rapidly.