2x Custom 15's in Ford Escape Review/ PICS

[snb778 5,000+ posts]

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anyone else..... this is all I have been told, thats what i've been building based on.... but 4x6" ports sounds a little overkill for 2x15's on 1200W each

 

[SSS 18734 5,000+ posts]

You are correct in saying that round ports *typically* require less port area in order to prevent port noise. This is because round ports minimize the amount of air moving alongside an edge. This friction causes turbulence and chuffing.

However, it does not mean that you have double the port area. If you calculated the ports as having 100+ square inches of port, your tuning is not what you think it is.

What is airspace in the box after all displacements, and how long are the ports?

 

[mazzasec 5,000+ posts]

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anyone else..... this is all I have been told, thats what i've been building based on.... but 4x6" ports sounds a little overkill for 2x15's on 1200W each

2 should be fine.

I am about to do 3 15"s with 3 6 inch aeros

 

[JHughes 10+ year member]

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anyone else..... this is all I have been told, thats what i've been building based on.... but 4x6" ports sounds a little overkill for 2x15's on 1200W each

All PVC ports are not aero ports. Aero ports are the ones with flared ends and they are the ports people have tested to be as efficient as almost double the port area but that doesn't mean you count them as double the area. A round port can be slightly more efficient than a slot port but not nearly as much without the flared ends. You should either flare the ends or add more PVC ports to get more port area for those 15s.

 

[mobeious 10+ year member]

aero ports are more efficiant to port noise then a slot port hince u dont need as big of a port to get away from the noise... but still doesnt mean that aero ports require half sq of port.... the reason people skimp on using the same SQ of aeros as a slot is... 1. cost 2. all the **** elbows ull prolly have to use to get the port length

 

[amartin_72]

Yeah looks like you need to check the math next time. The area of a circle is 3.14 times the radius squared and that's it. not multiplied by two not divided by two and nothing to do with the diameter. for 7.8 the minimum port would be 78 inches max 124 inches. With 2400w/ 6 straight pipe id start at 100 inches or 4 6's.

 

[tommyk90 5,000+ posts]

Need more port area, STAT!

3 6's should have been the minimum, especially for a box that size. You are reaching compression/maximum excursion too soon and thats why the bottom end falls so quickly.

 

[godhatescivics 10+ year member]

Just because the port is round doesnt mean that 2x the air moves through it. The port has the same cross sectional area. Your 6" PVC ports will move the same amount of air as a square port that is 5.31x5.31.
You dont understand how port area works. Ive had boxes for 15s with flared ports. Each 15 had 2 6" ports. You need more port area.

not really we been threw this before im rocking four axis 15s in 11 cubes on two 6 inch areos still doing 155s on music at 39 hrtz

 

[snb778 5,000+ posts]

omg... everyone is sayin different things now!!!?? what shall a guy do??

 

[Litunerkid 10+ year member]

very nice!

 

[snb778 5,000+ posts]

You are correct in saying that round ports *typically* require less port area in order to prevent port noise. This is because round ports minimize the amount of air moving alongside an edge. This friction causes turbulence and chuffing.
However, it does not mean that you have double the port area. If you calculated the ports as having 100+ square inches of port, your tuning is not what you think it is.

What is airspace in the box after all displacements, and how long are the ports?

airspace is 7.8 after displ. ports are 14.7" long... psp says 32hz.

omg... everyone is sayin different things now!!!?? what shall a guy do??

if aero's don't need 1/2 the port area, then how do you properly calculate it?

 

[ThatChevyGuy 5,000+ posts]

More Port!

 

[tommyk90 5,000+ posts]

not really we been threw this before im rocking four axis 15s in 11 cubes on two 6 inch areos still doing 155s on music at 39 hrtz

You also don't have nearly the amount of airspace per sub that he does, so you can get away with less port area.

 

[snb778 5,000+ posts]

but if you did a basic calculation, wouldnt a bigger box want more port area?

you think i should throw another port in there, or should I try to find some 6.5" tubes?

 

[tommyk90 5,000+ posts]

but if you did a basic calculation, wouldnt a bigger box want more port area?
you think i should throw another port in there, or should I try to find some 6.5" tubes?

Yes, that's exactly what I just said.

He only has 2.75 cubes per 15, you have almost 4.

More airspace per sub=need more port area for proper tuning.