Port Placement In a wall

[Julian 641]

I am designing my wall in my 95 Lumina, It is a four door Sedan. The wall will go up to the front seats. I was planning on making the port on the drivers side Vertically with two 18's like so

On the other hand my father said it would be better to do the port on the top or the bottom with the woofers above the port. Is this true?

[Duran 387]

What are your goals?

[Julian 641]

Basically to beat it daily and be able to compete with it

[loudcav 1]

it is typicly louder the way you designed it but it may not sound the best on music with the port being behind your head

[Julian 641]

Thats what i thought

[Duran 387]

To compete you'll want the style you designed, for music it will still be fine, sounding clean goes out the window with two 18's behind your head lol

[loudcav 1]

if by compete you mean Bass race Id go twards your dads suggestion it wont necisarily be louder but it should be alot better sounding even if you plan to burp it it should be OK

[Mac N Cheese 90]

To compete you'll want the style you designed, for music it will still be fine, sounding clean goes out the window with two 18's behind your head lol

x2

good luck on the build! and remember to do a build log

[Julian 641]

I think i have my final design ready. to make sure the port is not added into the enclosure? the width of the port is subtracted from it correct?

[Duran 387]

I think i have my final design ready. to make sure the port is not added into the enclosure? the width of the port is subtracted from it correct?

Are you talking about port volume? If so, it's not included in the NET volume. I don't know what you mean by subtracting the width.

[Julian 641]

Someone willing to check my math?

I came up with 13.92188 net with 195 inch of port tuned to 38hz im probably very wrong, I don't know yet

Edited December 30, 2009 by Julian

[Duran 387]

I came up with 16.50 Ft.³ NET tuned to 28.38 Hz. with 195 In.² surface area using 3/4" MDF all around.

Are you using double thick?

[lil_italy773 1]

i have 2 18"s in a ext cab s10 firing between the seats.

[Julian 641]

I came up with 16.50 Ft.³ NET tuned to 28.38 Hz. with 195 In.² surface area using 3/4" MDF all around.

Are you using double thick?

Yes double thick so it would be a thickness of 1.5inch

[shizzzon 461]

u can sound clean with a wall. Me and snoopdan's walls both sound clean on music so i don't know what the problem is there.

For competition, keep the design the way it is--> for burps and bassrace.

For Driveby, that is a toss up... It may be louder with a horizontal port but i have not and will probably never test that theory so i can't help there.

For strict daily driving, full horizontal port will work best because the port will not be made to load all in one precise area in the car.

[Duran 387]

I came up with 16.50 Ft.³ NET tuned to 28.38 Hz. with 195 In.² surface area using 3/4" MDF all around.

Are you using double thick?

Yes double thick so it would be a thickness of 1.5inch

Okay with 1.5" all around I get 13.86 Ft³ tuned to 30.97 Hz. with 195 In².

[Julian 641]

everything right except the tuning frequency! how can i get it to the 38 hz?

[Duran 387]

everything right except the tuning frequency! how can i get it to the 38 hz?

You want to tune that high?

[Julian 641]

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

[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.

[Julian 641]

is more port area a bad thing?

Edited December 30, 2009 by Julian

[Duran 387]

is more port area a bad thing?

No, it falls in the recommended range for your enclosure size. Between 189 and 252 In². With below recommended port area you will choke the subs, with too much port you risk mechanical failure.

[shizzzon 461]

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.

[Julian 641]

AQ requimends 16 inch per cuft that would equal 192 on the site it said fall within 10% of that number

[shizzzon 461]

if serious about competing, try and get as much port area as possible!

Recommended - 240sqin for average use.

350-500sqin for xtreme use. Do not use these numbers for daily use as stated before, strictly 1 note burps. It is up to the user to determine safe mechanical handling before unloading at port areas like this all at once.