An interesting type of slot port

[ghart999 0]

Basically I have seen some people recently making ported boxes and putting the slot port in the middle to act as bracing. When they get to the back of the box they split the port's area in two but still use the same port length.

You can see what I mean here:

http://www.caraudio.com/forum/showthread.php?t=169881

So for example if I needed 48 inches of port area, 30 inches long. I would go 3x16 in area for 15 inches and then make a left and right turn. The port area would shrink to 1.5x16 inches in both directions and go for another 15 inches in each direction. So technically I still maintained the same port area for the same length.

But I don't know if such a design actually is not the same as a typical L-shaped slot port and maybe changing the tuning freq, etc? Any thoughts on whether this is a good or bad idea? It certainly eliminates the need for bracing in a 36" long box...

Thank you.

[CBFryman 2]

It is the same.

but that type of port design seems like it would be bad for turbulence...so more port area would likely be needed to lower velocity so the turbulance wont be heard. I would think it would kill a few tenths on the mic too...so if you are chasing tenths for SPL its probably best to configure it some other way like making 2 1.5"x16" ports...though that would break the 1x9 rule of thumb. But then agian that is just a rule of thumb.

Fun isnt it?

[ghart999 0]

It is the same.

but that type of port design seems like it would be bad for turbulence...so more port area would likely be needed to lower velocity so the turbulance wont be heard. I would think it would kill a few tenths on the mic too...so if you are chasing tenths for SPL its probably best to configure it some other way like making 2 1.5"x16" ports...though that would break the 1x9 rule of thumb. But then agian that is just a rule of thumb.

Fun isnt it?

<{POST_SNAPBACK}>

Yeah I guess it would best to just to do a normal slot port with an L-turn and keep it simple stupid. I will still need to add a brace between the subs though. Thanks.

[rfpcreations 0]

i would also make the port as smooth as possible if spl is your concern, it looks like that person used some kind of texture paint.

Edited July 31, 2006 by rfpcreations

[mrray13 30]

it work's just fine, i've done it on more then a couple of occasions. turbalance shouldn't ba an issue as longa s the biggest part of your port as enough area...remember, you will be going from small to big, so speed will drop....

also, just a quick tip...a person does not need to paint the entire length of the port, or the backwall....after completing the enclosure, simply spray the mouth of the port and as far into it as you can. once the sub is installed, no light will pass and viola'...it's black (or whatever color you choose)

but do indeed roundover your edges...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[ghart999 0]

Cool. Thanks all.