How far does a port opening have to be from a car's wall

[whizdumb 10+ year member]

I am designing a box for my trunk and was wondering how much space must be between the opening of the port and the wall of the trunk? I am going to use 2 4" flared ports from partsexpress and was thinking it should be at least the diameter of the port?

Thanks! //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

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[SeanDub 10+ year member]

yeah, at the very least

 

[whizdumb 10+ year member]

Thanks for the reply, SeanDub!

I wasn't sure if anyone would be able to understand me, so I made a graphic to help illustrate:

Sorry I haven't quite gotten to the SketchUp stage...

So the least it should be placed from it, is one diameter? Would 6" be better? At what point would it not make a difference?

Thanks!

 

[IgnoreMe 5,000+ posts]

depends on the car

all though im sure most need at least about the diameter of the port, you will hear from all the jeep cherokee guys that the closer you are to the rear hatch up to about 1.5-2", i believe, you only gain, versus having 5" or whatever.

pretty weird in this case. my explorer likes about 4"

 

[whizdumb 10+ year member]

yeah that's kinda weird. Well thanks for the thoughts... My original plan (before the ports were going to the side like that) had the enclosure's wall 4" from the car's wall. I guess I could try it like that....

but I remember reading a thread that said if it was too close, it has the effect of lowering the tuning. Anyone heard this?

Back when I was thinking of getting an HD3, DJ was telling me to point the sub back and fire the ports to the side like this so I am thinking I will get decent SPL.

I am also probably going to make some sort of trim panel that will cover over the front of the box to make it one panel (so the back of the trunk will be one continuous wall).. do you think this would have any detrimental effects to the sound?

 

[IgnoreMe 5,000+ posts]

yeah that's kinda weird. Well thanks for the thoughts... My original plan (before the ports were going to the side like that) had the enclosure's wall 4" from the car's wall. I guess I could try it like that....
but I remember reading a thread that said if it was too close, it has the effect of lowering the tuning. Anyone heard this?

Back when I was thinking of getting an HD3, DJ was telling me to point the sub back and fire the ports to the side like this so I am thinking I will get decent SPL.

I am also probably going to make some sort of trim panel that will cover over the front of the box to make it one panel (so the back of the trunk will be one continuous wall).. do you think this would have any detrimental effects to the sound?

yup, that was probably my thread. seems it was just me worrying too much and letting my thoughts travel.

firing to the side has proven effect to people in grand prix and the like.

your best bet would be to make a thread asking what works best in your car from people that have experience.

 

[whizdumb 10+ year member]

Here's the thread I'm talking about. http://www.caraudio.com/forum/showthread.php?t=232356&highlight=port+distance It seems helotaxi agrees.....

I can't find a definitive answer if it matters or not. It seems like it would... but at what distance would it be OK? That probably depends on how much air is firing out too. [Gonna be a 15" TC-9 in a 3.5 cu ft NET w/ a Nine.1 (~1400 watts before rise) if it matters.]

I don't see a lot of people with my car on here.. gonna go search.

Anyway, IgnoreMe, thanks for all the replies.

 

[IgnoreMe 5,000+ posts]

Here's the thread I'm talking about. http://www.caraudio.com/forum/showthread.php?t=232356&highlight=port+distance It seems helotaxi agrees.....
I can't find a definitive answer if it matters or not. It seems like it would... but at what distance would it be OK? That probably depends on how much air is firing out too. [Gonna be a 15" TC-9 in a 3.5 cu ft NET w/ a Nine.1 (~1400 watts before rise) if it matters.]

I don't see a lot of people with my car on here.. gonna go search.

Anyway, IgnoreMe, thanks for all the replies.

i can guarantee you helotaxi is a guy you can trust. hes a VERY respected member around here and knows his shit.

with that said though, seems like the cherokees arent gonna follow that rule. or maybe they do, and lowering the tuning a bit helps them peak differently and the guys that tune to XXhz are actually tuned to XXhz because of being so close to that wall. i really dont know lol.

kinda hard to give you suggestions that may or may not help, since im not really experienced. im hoping someone else will jump in.

edit: after reading the thread again, i think helotaxi was actually reffering to the end of the ports inside the box being close to the back baffle of the box, and not front of the ports being too close to the trunk.

 

[helotaxi 5,000+ posts]

If you want the box/port to act as designed, give it at least the diameter of the port for clearance. Closer than that and the wall of the car starts acting like a loading wall. It might help the response and output, it might totally trash it. If you can experiment a bit try different distances and figure out what you like.

 

[whizdumb 10+ year member]

Wow, thanks for the info helotaxi! I guess I have to read up on loading walls..

This is going to be my first non-slot port build, so I still have to learn how aeroports can be mounted. I know they can be mounted on either flange, but what about somewhere on the middle straight section?

 

[helotaxi 5,000+ posts]

Port doesn't have to be entirely (or even partially) inside the enclosure.