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Calculating port area with xmax?


shanesauce

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Ok thanks.

If you missed my link this is a great way of flaring pvc ports to help tremendously with noise:

http://www.subwoofer-builder.com/flares-25mm.htm

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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Ok thanks.

If you missed my link this is a great way of flaring pvc ports to help tremendously with noise:

http://www.subwoofer-builder.com/flares-25mm.htm

Fuck it. too much work lol

I did calculate minimum port area for my subs, but it came out to be around 50^2 and 8" diameter. Which I think is just too much. So I decided to lower it to ~35-40^2 for 2 CF box.

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You can also take a round over to it, idk how well it will work but it's something.

Or you can get the precision ports as those can be reused in future boxes, or sold after used.

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

Well dang, sent me some PVC lol.

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

okay_sad_face_large.png

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

  • 2 years later...

yeass there we go that was the critical point in woofer specs that I was most curious about and wanted to learn the term for, thank you very much for putting it out there Vd=the peak to peak swept volume. Awesome.

Just to make sure - the formulas use Vd. That is the peak to peak swept volume, not one way Xmax.

I think your minimum calculates to 55 sqin, unless I misunderstood something.

In a car, you don't really have to have that much. The port may not operate 100% correctly at maximum driver excursion, but it will work.

Yes, an aero can have less port area. It eliminates a significant amount of port noise. Once again, the port may not operate 100% correctly, but as long as you don't get so small that the system begins to act like a leaky sealed box instead of a ported box, it will be fine.

I would guess ~30-35 sqin is enough for that pair of subs. Or you might could get decent results with one 4" aero.

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