Okay, I need to know if I designed this ported box right...

[SomeGuyDude 10+ year member]

Okay, so I didn't screw that up? That's what I needed to know.

 

[atlninja82 10+ year member]

nope its right.

 

[SomeGuyDude 10+ year member]

Sexcellent. Thanks a lot, man. And I can use RE's calculator to quickly get all my wood dimensions, get Lowe's to chop 'em up for free, borrow my uncle's Sawzall and I'm ready to start building.

Once I figure out if I'm buying a T5 or an RE SEX...

 

[atlninja82 10+ year member]

just be careful with lowes cutting for you. i have made the mistake of letting them do it for me a few times and i dont let them do it unless i have "my guy". theres only one guy that makes sure its right on or very close to it. so make sure you tell them you want as little error as possible or the cuts might be way off. good luck.

 

[SomeGuyDude 10+ year member]

Yeah. That's the problem. I don't have access to the necessary tools so I gotta hope for the best. Back when I was cutting the stuff myself I had a tendency to get the angles wrong. I'll have measuring tape with me when I go haha.

 

[atlninja82 10+ year member]

haha well go buy them. they will last you forever.

 

[ryls 10+ year member]

im pretty sure your port length would be 13.75 + .75 + 2.75 + .75 + 3. which would make it 21

actually isnt there another 1.5 inches of port length(half the width of the port) due to port end correction seeing as the port is on one of the enclosure walls

 

[atlninja82 10+ year member]

actually isnt there another 1.5 inches of port length(half the width of the port) due to port end correction seeing as the port is on one of the enclosure walls

im not sure i understand what you are saying. no i dont think there is another 1.5 inches

 

[SomeGuyDude 10+ year member]

im not sure i understand what you are saying. no i dont think there is another 1.5 inches

I know what he means. Eons ago guys would talk about something that I -believe- was dubbed "port correction" where basically you'd consider another few inches (half the width of the vent) inside the box as part of the port in all calculations. I think it came about because someone did some really rudimentary physics and didn't understand exactly what he was doing, but it caught on. Don't think it's legitimate though.

Actually I got lazy and started using this thing: http://www.reaudio.com/speaker_box/LPort_Box_Calc.html

Since I'm looking to make a box for a T4, this actually made things easier because the Soundstream manual says don't even take sub displacement into account, so I can do things straight as it says.

 

[ryls 10+ year member]

I know what he means. Eons ago guys would talk about something that I -believe- was dubbed "port correction" where basically you'd consider another few inches (half the width of the vent) inside the box as part of the port in all calculations. I think it came about because someone did some really rudimentary physics and didn't understand exactly what he was doing, but it caught on. Don't think it's legitimate though.
Actually I got lazy and started using this thing: http://www.reaudio.com/speaker_box/LPort_Box_Calc.html

Since I'm looking to make a box for a T4, this actually made things easier because the Soundstream manual says don't even take sub displacement into account, so I can do things straight as it says.

Here is a link that explain more what i was talking about

http://www.caraudio.com/forum/showthread.php?t=357091 there are alot more posts here and there about it in alot of other threads aswell. Also im pretty sure if your using the re calculator it is already adding in the port correction, but dosnt take into account sub displacement.

 

[dappa5 10+ year member]

if you increase the overall depth to 19.5 " you'll get 4.45 after port b-4 sub that's with a three inch prt idk if that port length is even valid just going off what you provided
hope this helped next time just post max dims and ask for suggestions plenty of ppl here will add their $0.02

ok so what are you looking for ??

It's been a while since I've done it, but here we go. My aim for the RE SEX15 was 4.0cu with a port at around 34Hz. Got 'em from the RE site
So here's what I did:

Then a 16.5x3" port, which means a length of 21.15" according to WinISD.

My final question: how does one factor in a bending vent? If it has to be 21"

i was under the impression that was what i provided ??

why are you arguing every answer you get??

w/e G/L with build

 

[SomeGuyDude 10+ year member]

Here is a link that explain more what i was talking about http://www.caraudio.com/forum/showthread.php?t=357091 there are alot more posts here and there about it in alot of other threads aswell. Also im pretty sure if your using the re calculator it is already adding in the port correction, but dosnt take into account sub displacement.

So I was right about the term? And yeah, I figured if it's a factor, RE would have it already as part of its equations, and as for displacement Soundstream's instructions even say "4.0ft^3 (w/o sub displacement)" so apparently that's not even a factor to them.

They also mention fiberglass insulation, so I'll have to snag some of that.

 

[atlninja82 10+ year member]

So I was right about the term? And yeah, I figured if it's a factor, RE would have it already as part of its equations, and as for displacement Soundstream's instructions even say "4.0ft^3 (w/o sub displacement)" so apparently that's not even a factor to them.
They also mention fiberglass insulation, so I'll have to snag some of that.

sub displacement is always a factor. they must have figured the volume needed was 3. somethin net and with the added sub displacement came out for 4 cubes even or close to it to make it easy.

 

[SomeGuyDude 10+ year member]

sub displacement is always a factor. they must have figured the volume needed was 3. somethin net and with the added sub displacement came out for 4 cubes even or close to it to make it easy.

Well yeah, that's what I mean. They have the numbers set so I don't have to worry about it on MY end. Which is convenient. I can just use round numbers.

So as it stands I'm looking at 16x16x38. Takes up the entire hatch from side to side but not too deep or tall. Question though: Is it possible to tune a box too low? If the manufacturer says 34Hz and I'm aiming at 33 or under, can that screw with the sub's potential somehow?

Second question: is 16" too short for a 15? I mean, the hole is 14.25" or something but am I cutting too close for actually mounting it? 17" wouldn't be a problem at all.

 

[atlninja82 10+ year member]

Well yeah, that's what I mean. They have the numbers set so I don't have to worry about it on MY end. Which is convenient. I can just use round numbers.
So as it stands I'm looking at 16x16x38. Takes up the entire hatch from side to side but not too deep or tall. Question though: Is it possible to tune a box too low? If the manufacturer says 34Hz and I'm aiming at 33 or under, can that screw with the sub's potential somehow?

Second question: is 16" too short for a 15? I mean, the hole is 14.25" or something but am I cutting too close for actually mounting it? 17" wouldn't be a problem at all.

1st question

i donno about that one. why would you want it that low dude? 34 is plenty low.

2nd

ive heard its recommended to leave atleast 3 inches on either side but you will be fine. i would just make sure wherever youre mounting it, make it a double baffle if possible.