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Good morning, I'm looking to do a 4th order with a single 10" skar sdr and need some help figuring out sealed, ported, and port size. I've done some calculations from online calculators but I just don't know if 1. I did it right or 2. If I should trust em. Any info or help I can get is appreciated

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You are gonna have to buy marine grade plywood because even if you bedliner spray it it would still get damaged by the weather. Do a 3:1 ratio and 16 square inches of port area per cubic foot. So if the ported section is 3 cubic feet the multiply 16 square inches by 3 cubic foot which would equal 48 square inches of port area. Make the port as close to a square as you can. Not a slot. And make sure wherever the subwoofer is mounted that you factor in the subwoofer displacement. Say the subwoofer is .1 cubic feet of displacement and the section the magnet is gonna be facing needs to be 1 cubic foot, then you add in that .1 cubic foot subwoofer displacement and whatever bracing displacements, let’s say it’s .03 cubic feet, and it would equal 1.13 cubic feet and that’s what that section has to measure to net 1 cubic foot. 

:stupid:“How can we help you?”
:guido:
“And don’t forget to tell them that 
the customer isn’t always right.”

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  • 4 months later...
On 8/11/2020 at 12:37 PM, 1point21gigawatts said:

You are gonna have to buy marine grade plywood because even if you bedliner spray it it would still get damaged by the weather. Do a 3:1 ratio and 16 square inches of port area per cubic foot. So if the ported section is 3 cubic feet the multiply 16 square inches by 3 cubic foot which would equal 48 square inches of port area. Make the port as close to a square as you can. Not a slot. And make sure wherever the subwoofer is mounted that you factor in the subwoofer displacement. Say the subwoofer is .1 cubic feet of displacement and the section the magnet is gonna be facing needs to be 1 cubic foot, then you add in that .1 cubic foot subwoofer displacement and whatever bracing displacements, let’s say it’s .03 cubic feet, and it would equal 1.13 cubic feet and that’s what that section has to measure to net 1 cubic foot. 

Does using a slot vs a square port make a big difference now that you say it i always see people do more squared ports on 4th orders but i thought it was just a personal preference. 

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10 hours ago, Marco said:

Does using a slot vs a square port make a big difference now that you say it i always see people do more squared ports on 4th orders but i thought it was just a personal preference. 

A square port creates better air flow. And do 20sq” of port area per cubic foot of the ported section if you are looking to get louder. And if you want better bandwidth, then do a smaller ratio like a 2:1 ratio. Tune it to 45hz. Port area and ratio can differ depending on build but tuning should always stay around 45hz. Tuning has nothing to do with bandwidth. Tuning is what it peaks at. The sealed section plays lower frequencies and the ported section plays higher frequencies. A larger ratio makes it louder but less bandwidth. A smaller ratio makes the enclosures bandwidth better but output is less. So more or less port area can help one or the other depending on other factors. Let me know what type of vehicle and subwoofers and amp.

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:stupid:“How can we help you?”
:guido:
“And don’t forget to tell them that 
the customer isn’t always right.”

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On 1/8/2021 at 9:20 PM, 1point21gigawatts said:

A square port creates better air flow. And do 20sq” of port area per cubic foot of the ported section if you are looking to get louder. And if you want better bandwidth, then do a smaller ratio like a 2:1 ratio. Tune it to 45hz. Port area and ratio can differ depending on build but tuning should always stay around 45hz. Tuning has nothing to do with bandwidth. Tuning is what it peaks at. The sealed section plays lower frequencies and the ported section plays higher frequencies. A larger ratio makes it louder but less bandwidth. A smaller ratio makes the enclosures bandwidth better but output is less. So more or less port area can help one or the other depending on other factors. Let me know what type of vehicle and subwoofers and amp.

Its going in a 17 malibu building a trunk wall, the plan is 2 skar svrs 12” on a massive n3 amp thats the end goal. Im ordering one sub at a time so i want to try the 4th for it never even seen one in person so it will help me decide wether to do a ported or 4th for the two subs once i get them. The single 12” is gonna be powered by a power acoustik 1500d ( i know not the best of amp but its a budget build so im using what i have.) i have a design in mind 2:1 ratio tuned to 50hz. Im not trying to win competitions so bandwidth over spl for me

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