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Port area. what does it affect?


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Unloading is based on port location not area.

Area can make positioning it hard to keep from unloading happening, but doesn't cause it.

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Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

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Again forgive my ignorance, I'm asking not saying you're wrong.

I have very limited knowledge of enclosures.

That being said a lot of people's definition of "music" is a clipped 30 hz sine wave with some 80 IQ knuckle head grunting about committing crimes and his genitals.

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It's all good.

And once again the area requirement was created to find the smallest it could be before noise was induced.

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Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

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All of these negatives and complications due to using vented enclosures is why I try to steer clear of using them.

However the acoustical gain in output is quite enormous when looking at SPL uses.

b_350_20_692108_381007_FFFFFF_000000.png

Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

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Share on other sites

I feel it's only a negative when you don't have the design right, such as not enough enclosure volume or port area and anything that that effects the life of the sub. People trying to push them past what they're rated for. I believe ratings are everything, if you want to push more power than what those subs are rated for, buy new ones to take it. Same thing with wiring low. You want more power, buy the amp to make it at its rated impedances.

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Holy crap this thread has a lot of activity.

No such thing as too much port area (at least within reason), there is such thing as too long of a port though, and since area and length are tied to tuning, you can definitely get yourself into a spot where your port is too big, because its too long.

Cone control problems will arise from not enough port area, not from too much.

Not having enough port will cause port compression. This makes your box start to act like a leaky sealed box. Output around tuining will drop, impedance will rise, output from your amp will decrease. You can check for this with an AMM-1 if you have one available.

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

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Very interesting thread. Kinda over my head but making me feel better about my big ass port lol.

System:

Pioneer DEH-8400BH

4 Alpine Type R 6.5's

4 Soundqubed PA 6.5's

4 Soundqubed Supertweets

Hifonics BRX 640.4

Crescendo S800/4

2 Soundqubed Q1-3500.1s strapped @1ohm

2 Soundqubed HDC4 18's

11 Cubes net @37hz (Subs up, port back)

2 DC Power 250 HD's

1 DC Power 300 SPX

DC Power triple alt bracket

5 Kinetik HC 1800's

4 runs of 1/0 OFC power cables

4 runs of 1/0 OFC grounds from rear battery bank to OEM alt bracket

iPad Air in dash

300+ sq ft or sound deadening

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If your port is too long you run into trouble with pipe resonance.

Pipe resonances will produce extra harmonic waves and in extreme conditions it can adversely affect your overall output.

I believe I talked with Triticum about this at one point and I think I said that you don't want your vent length longer then 1/4th the length of the frequency you're tuning to.

b_350_20_692108_381007_FFFFFF_000000.png

Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

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Share on other sites

However, everything can be explained through science.

If something messes up in the real world you have to look at every single variable and isolate that and manipulate it to see its affects.

b_350_20_692108_381007_FFFFFF_000000.png

Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

Link to comment
Share on other sites

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