Couple quick port questions.

[PapaGeno21 10+ year member]

Doing my first slot ported box.

I understand doing the 45 on the outside wall of the port in the corner of the box, but do I have to do anything to the inside wall? I am NOT going to do any kerf style cuts to round it out, so should I just leave that as the sharp L and then the outside wall has the 45?

Like this?

Or do I need to have it with both sides at the 45?

Now here is something that screws with me. How do I account for the corner?

Does this equal 20"?

Or does this and somehow the corner measures differently?

And as far as the face of the box, do I bust out the router to round over the port or does it not really matter?

90% of the boxes I see no one rounds over the outside of the slot port so I am just wondering if it is even necessary.

Thanks!

Click to read more...

 

[Sonic. 10+ year member]

Use drawing # 2, port width must remain constant, and the length of port is measured along the center line.

 

[PapaGeno21 10+ year member]

What do you mean it is measured along the center line?

 

[hispls 5,000+ posts]

What do you mean it is measured along the center line?

Draw a line down the center of the port and measure that. Then take into account the back wall will effectively extend the port by half a port width, so port may act a tad longer than you think.

Rounding anything will never hurt and looks good. Many people don't because they lack the tools.

 

[PapaGeno21 10+ year member]

Ok cool.

Now as far as pic 1 and 2. Do most people even bother? Doing pic 1 is easy, doing pic 2 is not so easy.

What happens if I do pic 1 with just a very small piece in the corner to help the bend, or will it still cut my port width down some?

 

[mklett33 10+ year member]

Ok cool.
Now as far as pic 1 and 2. Do most people even bother? Doing pic 1 is easy, doing pic 2 is not so easy.

What happens if I do pic 1 with just a very small piece in the corner to help the bend, or will it still cut my port width down some?

Yes people do bother, if you did picture one you would not have a consistent width. Its not as hard as it seems.

The videos in this thread should help a lot with some of your questions.

http://www.caraudio.com/forums/enclosure-design-construction-help/560833-about-make-thread-about-box-design-read-first.html

 

[PapaGeno21 10+ year member]

When I get home and on a comp I will watch those vids!

Do you need the 45's in the corners? Does it really make a difference that someone who isn't very into this stuff would notice?

 

[mat3833 10+ year member]

the port is all about smooth airflow. and the 45s help the air flow smoothly. you gain a little output as well as reduce port noise. its well worth it IMO. im going to go as far as using PVC pipe each corner for a completley smooth "U" bend AND routing the edge of the inner port wall ends if i can, if i cant i will be 45ing and still route the edge. but i will have a folded port, not an "L" port. im also tuning kinda low, and the lower you tune the issue of port noise becomes more of a concern.

i hope how i explained it makes sense.....

Matt

 

[PapaGeno21 10+ year member]

You did thanks man!

 

[mlstrass 5,000+ posts]

Without having a TL and tesing I would not start adding 45's. Some will hurt, some might help, no way to tell unless you test.

I have a box like pic 1, single HDC418 in the trunk of my daily beater. With 1500watts per USACI rules it did a 54.9 in the kick the other week, so pic 1 port style works just fine for daily/music...

 

[SMS 10+ year member]

Without having a TL and tesing I would not start adding 45's. Some will hurt, some might help, no way to tell unless you test.
I have a box like pic 1, single HDC418 in the trunk of my daily beater. With 1500watts per USACI rules it did a 54.9 in the kick the other week, so pic 1 port style works just fine for daily/music...

thats some crazy #s with a 18 in a trunk off 1500w.

guy i know gets that with 2 18" XLs off 5k- on the dash

 

[jdawg 5,000+ posts]

will you tell a difference in a daily system without 45s? probably not. Chasing tenths no a TL? You might tell a difference, if you have the tools to cut a 45 and round the mouth and edges easily go ahead and do it. If its a hassle dont worry about it.

 

[mklett33 10+ year member]

the port is all about smooth airflow. and the 45s help the air flow smoothly. you gain a little output as well as reduce port noise. its well worth it IMO. im going to go as far as using PVC pipe each corner for a completley smooth "U" bend AND routing the edge of the inner port wall ends if i can, if i cant i will be 45ing and still route the edge. but i will have a folded port, not an "L" port. im also tuning kinda low, and the lower you tune the issue of port noise becomes more of a concern.
i hope how i explained it makes sense.....

Matt

KERF! DEWHF@#*$@)

http://www.caraudio.com/forums/enclosure-design-construction-help/531017-kerfing-101-how-kerf-mdf-curved-port-applications.html

 

[mklett33 10+ year member]

will you tell a difference in a daily system without 45s? probably not. Chasing tenths no a TL? You might tell a difference, if you have the tools to cut a 45 and round the mouth and edges easily go ahead and do it. If its a hassle dont worry about it.

this.

To me, I am OCD about anything I make, so it get's 45's and kerfed, I dont ike knowing that something wasn't the best it could possibly be, does it make much of a difference, not really for daily driving, but still like I said, Im OCD.

 

[mlstrass 5,000+ posts]

this.
To me, I am OCD about anything I make, so it get's 45's and kerfed, I dont ike knowing that something wasn't the best it could possibly be, does it make much of a difference, not really for daily driving, but still like I said, Im OCD.

Without a TL how do you know it's "the best it could be"?

I did some testing on a 4th order build I did over the summer and added 4" PVC roundovers to various places inside the enclosure. I lost .3 - .6 everywhere I tried them. Would you hear that to the ear, obviously not, but just because on paper it looks good that doesn't mean it really is...