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re-tuning my box. Nightshade 18


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SO after buimpin around for almost a year i realized my port area was WAAAAAAYY too small. :pardon:

Im having a few issues due to the way this box has to be built.

Its sub up and the port shoots up through the rear deck of my car, because of this my options for my port is pretty restricted.

Gross volume: 6.24ft^2

Port volume 1.00ft^2

Net volume 4.57ft^2

basically using torres' calc im getting a port area range of 55-73in^2, but to make the box fit my trunk im needing to go with 80in^2... Is this a problem?

the other thing im concerned about is the fact that the port area per foot seems high, its 17.49in^2

Too much?

The tuning freq ends up being 36.49hz, which is a littler higher than i would have liked, but im not overly concerned with that.

Pioneer x930 bt

Rockford t2500 bdcp

18" nightshade v1

DC audio 175.4

RF power T162s up front, infinity 3 way 6x9's in the back (removing rear stage and re-doing doors soon)

3x XS power D2700's

Knukonceptz 0awg all around

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Can you get a screenshot of the Torres showing the parameters, it's hard to understand why you say that you need a larger port area to fit the box, in any case your port does not need to go all across if that's your problem, if you can't upload the screenshot just give the external dims you intend to use.

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Can you get a screenshot of the Torres showing the parameters, it's hard to understand why you say that you need a larger port area to fit the box, in any case your port does not need to go all across if that's your problem, if you can't upload the screenshot just give the external dims you intend to use.

the only reason i need a larger port is because of my car, its hard to explain...

I actually may have solved my own problem though:

Here is the screen shot

p46hL.png

Ther depth and width are so odd because i already built the bottom and sides of the box and it came out 1/8th of an inch bigger than it was supposed to, haha.

Edited by JZeFF

Pioneer x930 bt

Rockford t2500 bdcp

18" nightshade v1

DC audio 175.4

RF power T162s up front, infinity 3 way 6x9's in the back (removing rear stage and re-doing doors soon)

3x XS power D2700's

Knukonceptz 0awg all around

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Since port area is not determined by box volume, don't stress too much.

Edit - I missed the entire title (on my phone). Eighty sqin is definitely not too much port for a NS 18. I would go up to 100 sqin.

Very seldom would you ever have too much port area in a car enclosure, so as long as you can get the length you need for the tuning you want, you will be fine.

Edited by bkolfo4

Current system:

1997 Blazer - (4) Customer Fi NEO subs with (8) American Bass Elite 2800.1s

Previous systems:

2000 Suburban - (4) BTL 15's and (4) IA 40.1's = 157.7 dB at 37 Hz.

1992 Astro Van - (6) BTL 15's and (6) IA 40.1's = 159.7 dB at 43 Hz.

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Since port area is not determined by box volume, don't stress too much.

Edit - I missed the entire title (on my phone). Eighty sqin is definitely not too much port for a NS 18. I would go up to 100 sqin.

Very seldom would you ever have too much port area in a car enclosure, so as long as you can get the length you need for the tuning you want, you will be fine.

Thanks bud, that's exactly the kind of answer i was looking for.

Just wanted to make sure i was on the right track before i start building the port.

Pioneer x930 bt

Rockford t2500 bdcp

18" nightshade v1

DC audio 175.4

RF power T162s up front, infinity 3 way 6x9's in the back (removing rear stage and re-doing doors soon)

3x XS power D2700's

Knukonceptz 0awg all around

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im assuming having a tuning of like 38hz isnt going to kill my low end too bad?

I tend to listen to rap, but honestly, i have never been a fan of the super low notes (like waddle by gorilla zoe, etc)

Edited by JZeFF

Pioneer x930 bt

Rockford t2500 bdcp

18" nightshade v1

DC audio 175.4

RF power T162s up front, infinity 3 way 6x9's in the back (removing rear stage and re-doing doors soon)

3x XS power D2700's

Knukonceptz 0awg all around

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It won't kill your low end just wont be as strong down low, but you will need to be a little more careful on how much power your pushing to it, if your over powering it you may do some harm playing a lot of lows for whatever reason...

All in all I personally don't see a problem say you should be perfectly fine

Laying frame soon.. System has to wait

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This gives the best idea of what im doing... the port NEEDS to shoot out of the box at the point that it does so that it lines up with the rear deck.

You can see from the circle on the 2 baffles where the sub will be going. The 2 rectangles in the baffles is just because the port is external.

3pW74.png

is there any MAJOR problems with this design? obviously i would like to get the sub further away from the port opening, but its just not going to happen.

i end up with 96"^2 port area, 21"^2 port area per foot.

And a tuning of 38 hz.

Pioneer x930 bt

Rockford t2500 bdcp

18" nightshade v1

DC audio 175.4

RF power T162s up front, infinity 3 way 6x9's in the back (removing rear stage and re-doing doors soon)

3x XS power D2700's

Knukonceptz 0awg all around

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If it was me, I would want the tunIng around 34 for daily. I have had a couple of boxes at 38-40 and they do lack a little on songs with really low bass.

If you stick with 38, just make sure your subsonic filter is set correctly to keep the mechanical excursion under control (you did not mention how much power you are running).

Current system:

1997 Blazer - (4) Customer Fi NEO subs with (8) American Bass Elite 2800.1s

Previous systems:

2000 Suburban - (4) BTL 15's and (4) IA 40.1's = 157.7 dB at 37 Hz.

1992 Astro Van - (6) BTL 15's and (6) IA 40.1's = 159.7 dB at 43 Hz.

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