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Designing a ported/4th/6th box specifically for strong lows


juan777

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Let's forget about subs for a second, assume you have amazing subs that can play very low or high. How would you tune a Sub box to play very strong lows?

I don't mean "How do you tune a box to a certain freq?" either, I mean "How can I design a box to play low?"

I have heard "lots of port area" "less port area" "1 port" "Multiple ports" and many other contradicting answers.

And for that matter how do you design a box for a strong high performance?

Building tutorials and tips are welcome

Once again, NOT ASKING HOW TO TUNE A BOX, this question is about box design and optimization.

The L@zy Hoe

 

 

2005 Chevy Tahoe

2,500 Watts of Highs/Mids

4 10 midrange

4 6.5 midwoofers

4 Tweeters

6 Supertweeters

2 Lithium 80AH Batteries

24K Watts

4 Custom 18s

Quad alt setup Rebuilt 250amp and 3 370s

Interior work by Lone Star Auto Works

 

The Build Log

Like Loud Bass? Click Here!

 

On 12/5/2014 at 8:06 PM, juan777 said:

See yall there, I'll be the drunk Mexican with aviators on.

On 12/6/2014 at 10:32 PM, boom50cal said:

I did see Juan LMFAO! He REALLY WAS the drunk mexican with Aviators on!

 
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^^^i'd say that's right on point, especially when working with 4ths and 6ths, so I hear...no matter how sweet it looks in design, you never really know till you slap it in there.

2007 Chevy Aveo Ls sedan

2 Sundown Xv2 on scv4k @ .5 ohm

2 pair RE XXX 6.5 components on sax200.4 @ 2 ohm

Big Three, Three runs 1/0 power from front to back, 1 ground front to back

Two runs ground from rear bank to chassis

XS power d3100 upfront, 3 Odyssey 2150s in bank

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Quick question. Normally when you tune a ported box it will peak higher than on paper or on win isd. Does this also occur in 4th order and 6th order boxes?

I know in my car I wanted it to peak in the mid 30s. So I had to tune in the high 20s.

03 Sable LS

AA mayhem 12" D2

Sundown ZV4 12" D1

Tantric HD 12" D2

Tantric SHD 12" D1

Sundown X12 V2 D2

2.5 cu net

Sundown 2000d @ 1 ohm

XS Power XP2000

Sky High Sound Deadener

Sky High wire

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Quick question. Normally when you tune a ported box it will peak higher than on paper or on win isd. Does this also occur in 4th order and 6th order boxes?

I know in my car I wanted it to peak in the mid 30s. So I had to tune in the high 20s.

The important thing to remember here is that the output from the box is not changed by being in your car. If you build a box with a moderate hump in output at 30 Hz, it is going to have that 30 Hz hump whether it is in your car, in your house, or out in the middle of a field. What changes is how your car effects that output (i.e. cabin gain). If your car naturally significantly boosts output at 40 Hz, its going to boost 40 Hz no matter what kind of box you have in there (though placement in the vehicle does have a big impact, along with other factors). This is why your car peaks higher than what your box is tuned to. What the box outputs and the acoustic effects of your car are both components that add together to determine what your car is going to end up sounding like.

So to answer your question, if your car naturally has a peak at some frequency with a ported box it is going to have a similar peak with a 4th or 6th order bandpass as well, assuming they are in the same location as the ported box was.

"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:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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Quick question. Normally when you tune a ported box it will peak higher than on paper or on win isd. Does this also occur in 4th order and 6th order boxes?

I know in my car I wanted it to peak in the mid 30s. So I had to tune in the high 20s.

The important thing to remember here is that the output from the box is not changed by being in your car. If you build a box with a moderate hump in output at 30 Hz, it is going to have that 30 Hz hump whether it is in your car, in your house, or out in the middle of a field. What changes is how your car effects that output (i.e. cabin gain). If your car naturally significantly boosts output at 40 Hz, its going to boost 40 Hz no matter what kind of box you have in there (though placement in the vehicle does have a big impact, along with other factors). This is why your car peaks higher than what your box is tuned to. What the box outputs and the acoustic effects of your car are both components that add together to determine what your car is going to end up sounding like.

So to answer your question, if your car naturally has a peak at some frequency with a ported box it is going to have a similar peak with a 4th or 6th order bandpass as well, assuming they are in the same location as the ported box was.

Thanks for the informative answer. Helped me out.

03 Sable LS

AA mayhem 12" D2

Sundown ZV4 12" D1

Tantric HD 12" D2

Tantric SHD 12" D1

Sundown X12 V2 D2

2.5 cu net

Sundown 2000d @ 1 ohm

XS Power XP2000

Sky High Sound Deadener

Sky High wire

Stock alt

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What about in general? I have heard that you can get a box to play better lower if your port area is right around 12in per cuft maybe even less. The reasoning being that it will act a bit more like a sealed enclosure.

Same concept seems to apply to enclosures that are designed for highs, not a lot of boxes are built for "highs" outside of burp boxes but I have heard some people will have port area in the 18in per cuft.

Any truth to that?

The L@zy Hoe

 

 

2005 Chevy Tahoe

2,500 Watts of Highs/Mids

4 10 midrange

4 6.5 midwoofers

4 Tweeters

6 Supertweeters

2 Lithium 80AH Batteries

24K Watts

4 Custom 18s

Quad alt setup Rebuilt 250amp and 3 370s

Interior work by Lone Star Auto Works

 

The Build Log

Like Loud Bass? Click Here!

 

On 12/5/2014 at 8:06 PM, juan777 said:

See yall there, I'll be the drunk Mexican with aviators on.

On 12/6/2014 at 10:32 PM, boom50cal said:

I did see Juan LMFAO! He REALLY WAS the drunk mexican with Aviators on!

 
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What about in general? I have heard that you can get a box to play better lower if your port area is right around 12in per cuft maybe even less. The reasoning being that it will act a bit more like a sealed enclosure.

Same concept seems to apply to enclosures that are designed for highs, not a lot of boxes are built for "highs" outside of burp boxes but I have heard some people will have port area in the 18in per cuft.

Any truth to that?

The "port area per cube" rule is a very simplistic method for determining how much port to use. While it may get you in the ballpark sometimes, the problem with it is its an incomplete answer. Using the "port area per cube" rule a 12 mm xmax sub on 400 watts would use the same port as a 30 mm xmax sub on 3K watts as long as the box they went in had the same volume. Obviously that's not going to be ideal in one or probably both situations. For this reason building a box with 12 sq in per cube to hit low notes better is an equally incomplete methodology.

Short answer: no there is not any truth to that, at least in my experience.

"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:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

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So no way to tell without testing I guess. That's half the fun anyway!

Thanks everyone

The L@zy Hoe

 

 

2005 Chevy Tahoe

2,500 Watts of Highs/Mids

4 10 midrange

4 6.5 midwoofers

4 Tweeters

6 Supertweeters

2 Lithium 80AH Batteries

24K Watts

4 Custom 18s

Quad alt setup Rebuilt 250amp and 3 370s

Interior work by Lone Star Auto Works

 

The Build Log

Like Loud Bass? Click Here!

 

On 12/5/2014 at 8:06 PM, juan777 said:

See yall there, I'll be the drunk Mexican with aviators on.

On 12/6/2014 at 10:32 PM, boom50cal said:

I did see Juan LMFAO! He REALLY WAS the drunk mexican with Aviators on!

 
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