Port Area

[thebiggmann12 14]

Alright, so im working on a design for a new box for my NS 18. i am running a saz1500d on stock alternator and soon to be (hopefully) a new xs power battery(probably d5100) im gonna do it right at 5 cubes tuned to 35hz, so it will still be good for daily, and get me a little more spl for when i compete. so since i plan on competing as much as possible i was wondering how much port area to have. ik everybody says 12-16 but i was wondering if i should go more or less or just stick within that range. ik there are some people on here that are really smart when it comes to this subject so thanx in advance. also, is 35hz a good tuning for daily and a little bit of competing or should i go higher, i dont listen to much that peaks really low normally in the 35-40hz range.

[Duran 387]

Given the Nightshade xmax, which I'm estimating to be 27mm, you will need a minimum of 145² inches of port area.

[thebiggmann12 14]

in 5 cubes?

[stealth 113]

no dont listen to him. if your going for daily with a little more output, you could go 35-38hz with 15-17 per and you should be fine. that should give you a good star off point. then you can redo the box to your liking. also you should figure out what freq your car likes, or simply do 2 boxes. 1 daily, 1 comp.

[slim2fattycake 85]

Given the Nightshade xmax, which I'm estimating to be 27mm, you will need a minimum of 145² inches of port area.

Where did you get that number?

And OP, if you want to save space and be able to do daily and competition easier, Use aero ports. Get some 6" aeros and you can just switch them out when you go to competition with your car's peak tuning. You won't do as well if your peak no where near your daily tune.

[thebiggmann12 14]

well i dont wanna use aeroports bc they are soooo expensive, and i wont be competing ALOT just every now and then. id like to just stick with a slot port.

[94sundance 0]

well from some of my own expierince areo ports for daily and competing are better they sound smoother and well just like my SSA sig says \/

[Duran 387]

in 5 cubes?

Enclosure size doesn't come into play. You build the vent to the driver specifications, not the enclosure.

[lithium 358]

Given the Nightshade xmax, which I'm estimating to be 27mm, you will need a minimum of 145² inches of port area.

how did you calculate this

[Duran 387]

no dont listen to him. if your going for daily with a little more output, you could go 35-38hz with 15-17 per and you should be fine. that should give you a good star off point. then you can redo the box to your liking. also you should figure out what freq your car likes, or simply do 2 boxes. 1 daily, 1 comp.

Making that recommendation doesn't tell him the exact minimum amount of port area needed to avoid port noise.

[Duran 387]

Given the Nightshade xmax, which I'm estimating to be 27mm, you will need a minimum of 145² inches of port area.

how did you calculate this

Dmin = 2030(Vd²/Fb)^1/4/Sqrt Np

[stealth 113]

no dont listen to him. if your going for daily with a little more output, you could go 35-38hz with 15-17 per and you should be fine. that should give you a good star off point. then you can redo the box to your liking. also you should figure out what freq your car likes, or simply do 2 boxes. 1 daily, 1 comp.

Making that recommendation doesn't tell him the exact minimum amount of port area needed to avoid port noise.

so you are telling me that he will have port noise with 15-17 per and it will be audible???? are you a dumbass, or just a dumbass.

my recommendation is not telling him the minimum amount or port area needed without port noise, its giving him a proper starting point for a daily system with lots of output.

[jcarter1885 995]

Given the Nightshade xmax, which I'm estimating to be 27mm, you will need a minimum of 145² inches of port area.

29in^2 per cube(for a 5ft^3 ported enclosure) seems like a lot even if you dont go by enclosure size.

[lithium 358]

Given the Nightshade xmax, which I'm estimating to be 27mm, you will need a minimum of 145² inches of port area.

how did you calculate this

Dmin = 2030(Vd²/Fb)^1/4/Sqrt Np

good lord i have to do real math... im this hobby to stray away from this kind of shit lol.. just kidding im a physics major so me > maths lol

thanks for the eq.

[Julian 641]

no dont listen to him. if your going for daily with a little more output, you could go 35-38hz with 15-17 per and you should be fine. that should give you a good star off point. then you can redo the box to your liking. also you should figure out what freq your car likes, or simply do 2 boxes. 1 daily, 1 comp.

Making that recommendation doesn't tell him the exact minimum amount of port area needed to avoid port noise.

so you are telling me that he will have port noise with 15-17 per and it will be audible???? are you a dumbass, or just a dumbass.

my recommendation is not telling him the minimum amount or port area needed without port noise, its giving him a proper starting point for a daily system with lots of output.

^^^^^^^^^^^^^^^^^^^^^^^^^

Edited March 15, 2010 by Julian

[Duran 387]

no dont listen to him. if your going for daily with a little more output, you could go 35-38hz with 15-17 per and you should be fine. that should give you a good star off point. then you can redo the box to your liking. also you should figure out what freq your car likes, or simply do 2 boxes. 1 daily, 1 comp.

Making that recommendation doesn't tell him the exact minimum amount of port area needed to avoid port noise.

so you are telling me that he will have port noise with 15-17 per and it will be audible???? are you a dumbass, or just a dumbass.

my recommendation is not telling him the minimum amount or port area needed without port noise, its giving him a proper starting point for a daily system with lots of output.

While it will reduce port noise your recommendation will make mechanical failure more likely. My estimation gives the OP the minimum amount of port area needed to reduce the likelihood of port noise as well as reduce the chances of mechanical failure.

You recommending 15-17 proves your stupidity and your lack of understanding of enclosure design. Stop making recommendations as all of them have been proven incorrect.

[Duran 387]

Given the Nightshade xmax, which I'm estimating to be 27mm, you will need a minimum of 145² inches of port area.

29in^2 per cube(for a 5ft^3 ported enclosure) seems like a lot even if you dont go by enclosure size.

If I had the exact xmax it would be more accurate, I estimated it to be 27mm.

[thebiggmann12 14]

should i get the exact xmax or should i just go with 145sq in? bc i can email jacob about it...lol he probably hates me with all the emails i send him.

[Duran 387]

should i get the exact xmax or should i just go with 145sq in? bc i can email jacob about it...lol he probably hates me with all the emails i send him.

We should use the exact xmax, yes.

[thebiggmann12 14]

alright i will email jacob tonight. thanx bro.

[jcarter1885 995]

Well I appreciate it, will definitely get those figures from Jacob tomorrow so I can find a port length for my new enclosure since I may not have enough port area.

[antonmiller 8]

The Subwoofer DIY Page - Port Calculations

little bit of info here.

[thebiggmann12 14]

jacob said Approx 25mm linear each way. he also said 64 in squared should do it.

[Argent Audio 54]

It is also very simple to model a driver/enclosure combo in WinISD to see the actual feet per second that air will have flowing in and out of the port.

Andrew

[thebiggmann12 14]

lol i have no idea how to do that.