Port Placement In a wall

[Duran 387]

misinformation here...

Assuming displacement is 0.25 per sub=0.5cuft

Using 1.5" thick walls all the way around the box(6 sides)

Assuming the 6 1/2" is the port opening on the far right...

Assuming the port depth goes back 15.5" internally leaving 6 1/2" opening in the back...

Assuming the 18s will be flush mounted into the baffle..

Assuming added port wall is single layered(recommended)

I get 13.15cuft

Port area 175.5sqin 6.5" x 27"

Port depth physical - 17" \ 15.5" internal.

Port depth acoustical- 27.5"

Tuning - 30.5hz

For 38hz -

Port depth physical - 7.5" \6" internal.

Port depth acoustical - 10.75"

Please note that ANY mass added to the inside of this box will throw off tuning. The more mass you take up, the higher the tuning will go so if you want 45s in the corners then gotta know beforehand.

Also, when bracing this thing, do as MUCH as possible to the outside when designing for competition.

Try to brace adjacent walls to each other if you can't brace your box to the car or build a steel frame or layered wood around it.

Where exactly is the misinformation? Look at our enclosures, they are both different of course we'll get different tuning.

[shizzzon 461]

there isn't enough information posted from the user for me to get exact numbers.

I don't really see how you even got numbers without all the info i posted about assuming this and so on...

[Julian 641]

That's what AQ recommendeds for the HDC3 18's

Increase port width to 8" with no length it's tuned to 38.44 Hz. with 240 In².

What do you mean by "No length"?

[Duran 387]

That's what AQ recommendeds for the HDC3 18's

Increase port width to 8" with no length it's tuned to 38.44 Hz. with 240 In².

What do you mean by "No length"?

My design is built with no port length, the physical port length will be 0.

[Julian 641]

i see.

[shizzzon 461]

that's suppose to mean just use baffle depth but uh.. how u get that?

Either i'm lost or there is some serious misguided math goin on here...

the baffle is double layered correct?

If that's true the internal volume needs to be about 22cuft to have a "no length" when using 27x8"

You are using 8x30"... there is no where in this thread that he mentioned that the dimensions posted were internal dimensions so i am subtracting 1.5" thick all the way around what he has posted.

If this is incorrect, Julian, you need to clear this up as you will have 2 totally different answers.

[Julian 641]

I'm utterly confused to be honest. It should be external dimensions. I PMed you Shizzzon not to long ago about designing a wall for me.

[Duran 387]

I was making my enclosure based on this picture. I should have clarified if that was the outside dimensions, that's how I designed mine.

[shizzzon 461]

i'm bout to go to sleep but i assumed that is external so-

47" internal wide

27" internal high

22" internal deep

Ok, well i might tackle this tomorrow but i got some more box designs to take care of first....

[Julian 641]

i'm bout to go to sleep but i assumed that is external so-

47" internal wide

27" internal high

22" internal deep

Ok, well i might tackle this tomorrow but i got some more box designs to take care of first....

you're about to have PM

[Julian 641]

i'm bout to go to sleep but i assumed that is external so-

47" internal wide

27" internal high

22" internal deep

Ok, well i might tackle this tomorrow but i got some more box designs to take care of first....

you're about to have PM