help with port for a Fi 15" SSD

[C-Bass 10+ year member]

I'm well into my box building project. The remaining issue is the port.

I have 3.8 cuft box I want tuned to 33Hz

The online calculator stuff I've used comes up with a slot port of 6"W x 3" H x 5.22" L which seems small to me.

Can someone point me in the right direction here. I don't have a lot of room to work with either about 8" on either side of the sub

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[BJ The Man 10+ year member]

is it already built and your putting the port in? and what car are you putting this in and maybe some pics would help for starts.

 

[shavenblazer 10+ year member]

I had 4 cubes with 3 4in aero ports @32hz for mine and it wannged.

 

[C-Bass 10+ year member]

is it already built and your putting the port in? and what car are you putting this in and maybe some pics would help for starts.

The box is mostly built, I just have to get the port sorted out and fiberglass what will become the baffle.

I originally used some of the online calculators you can find to get my port area, but when I double checked with some people that are "in the know" they all said it looks too small for the woofer. That's why I'm confused. I thought a formula is a formula...

The car it's going in is a 64 Impala, but there is VERY limited room in the trunk

 

[C-Bass 10+ year member]

I had 4 cubes with 3 4in aero ports @32hz for mine and it wannged.

How long were the ports?

 

[Immacomputer 10+ year member]

The usual way of doing these things is coming up with a design BEFORE starting to build.

It doesn't look like you have anywhere near enough room to port. It also doesn't look like you have anywhere near 4 cubes either.

 

[C-Bass 10+ year member]

I did have a design BEFORE I started to build, using the same formulas as I have in years gone by. Everything had more than enough room as per my original design.

As I was posting a build up on another site someone mentioned they didn't think I had enough port area, but nobody has been able to say why. I didn't just pull these numbers out of the air, I used the standard formula for calculating ports like I have done in the past.

As far as it "looking" like I don't have near 4 cubes...my measurements say different. It's also in the trunk of a 64 Impala, which if you're not familiar with is HUGE....that might be a reason why it "looks" small to you

I'm by no means an expert, but just because I have 4 posts on this site doesn't mean I've never done this before.

The reason I came to ask what the deal was is I have always built my boxes the same way (with very good results) and I'm not understanding as to why I need so much more port this time around. Each time I've done this in the past, I've used the same formula.

 

[tuck05 10+ year member]

The car it's going in is a 64 Impala, but there is VERY limited room in the trunk.....

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[DaveT 10+ year member]

...

I think he is referring to there being limited room with the batts and looks like it may have hydros or bags.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[C-Bass 10+ year member]

It's got hydros and 6 batts in the trunk. They're currently removed for obvious reasons

 

[Immacomputer 10+ year member]

I did have a design BEFORE I started to build, using the same formulas as I have in years gone by. Everything had more than enough room as per my original design.
As I was posting a build up on another site someone mentioned they didn't think I had enough port area, but nobody has been able to say why. I didn't just pull these numbers out of the air, I used the standard formula for calculating ports like I have done in the past.

As far as it "looking" like I don't have near 4 cubes...my measurements say different. It's also in the trunk of a 64 Impala, which if you're not familiar with is HUGE....that might be a reason why it "looks" small to you

I'm by no means an expert, but just because I have 4 posts on this site doesn't mean I've never done this before.

The reason I came to ask what the deal was is I have always built my boxes the same way (with very good results) and I'm not understanding as to why I need so much more port this time around. Each time I've done this in the past, I've used the same formula.

I don't give a **** how many posts you have and it matters not. What "formula" are you using to get port area. If you were planning on using 18in^2 of port area, you would get a lot of port noise and things would sound terrible.

What other enclosures have you built (I'm looking for size and port specs)? For what subs? With what kind of power?

You may be able to get away with a slot port heading back into that top area you have there but without dimensions, there is no way to know.

 

[C-Bass 10+ year member]

I don't give a **** how many posts you have and it matters not. What "formula" are you using to get port area. If you were planning on using 18in^2 of port area, you would get a lot of port noise and things would sound terrible.
What other enclosures have you built (I'm looking for size and port specs)? For what subs? With what kind of power?

You may be able to get away with a slot port heading back into that top area you have there but without dimensions, there is no way to know.

If you don't know of any formulas to calculate ports I doubt you can help me.

Past enclosures have nothing to do with anything in this post...

the dimensions for the "top" part are 35.5" W x 5.5" H x 16.5" L

 

[Immacomputer 10+ year member]

If you don't know of any formulas to calculate ports I doubt you can help me.
Past enclosures have nothing to do with anything in this post...

the dimensions for the "top" part are 35.5" W x 5.5" H x 16.5" L

I know them plenty well. I'm curious as to how you figure how much port area you should use...

What about dimensions to the other parts of the enclosure? I can possibly make a sketchup of it and see how a possible port could fit. With that sub, you're going to want about 40-50in^2 of port area.

I would actually run that sub sealed but it shouldn't sound bad in about 3.5 cubes at 32hz or so.

 

[C-Bass 10+ year member]

ok for example...the 12volt port length calc

the formula they claim to use is ((14630000*(D/2)*(D/2))/((Fb*Fb*Vb*1728)-(1463*(D/2))))

I use 4" as the diameter simply because someone mentioned 4" aero port

box volume 3.8 cuft tuning 33 Hz Length = 5.22 inches

the bottom part of the box 34.5 x 12 x 8

the triangular middle part is 13.5 x 11 x 17.5

that's all internal dimensions also.

 

[shavenblazer 10+ year member]

How long were the ports?

21 inches.