Is AQ right on how they say to tune a box?

[CoilBurner]

Trying to put an HDC3 18 into a malibu with a slot port to AQ's box specs.. Need to confirm this box is tuned to what I think it is though... The box is 24.5" wide X 29' tall X 18" deep. Using 1/2" wood. Works out to 6.4 cubes before any displacements

On AQ's site under box construction, he says that the way to tune a box to 40hz is by recommending 16^2 port per cube, multiplied by your box volume to get port area.

So for me thats 16 X 6.4 = 102.4" of port area needed.

It says that if I use that port area 16" deep, that the box will be tuned to about 40hz....

BUT

How come EVERY SINGLE box calc gives port lengths MUCH longer??

I know my box will have to have an L in the port because Im only going to have 18" depth but I dont know how long to make it for the tune I want.. Heres a pic of my box I wanna build. My port would be 3.6" wide and 28" tall internally to get that port area

But I am unsure if the length should actually be 16" for the 40hz tune.

Click to read more...

 

[thehardknoxlife 10+ year member]

1/2" wood for an 18"? You'll need to bump it up to 3/4" wood and a double baffle. What's your max dimensions?

 

[modskwod 10+ year member]

According to my calculations your port would need to be 15 1/4 inches long to get a tuning of 40 hz. That's assuming the woofers displacement is ~.2 cubes, which is fairly close to most 18's.

Oh and 1/2 inch wood = //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif Your box will probably explode.

 

[I Like Waffle]

lulz at .5 mdf

 

[mlstrass 5,000+ posts]

16" long for 16^2 of port area is 40Hz. I've built a TON of AQ/DD boxes. Port area is based on NET volume, not gross...

1/2 mdf = fail

also you're net volume is going to be pretty small as AQ's like big enclosures to get the most out of them.

 

[kr15 5,000+ posts]

1/2 mdf is only suitable for Sony Xplod 10s and Pyle 12s

 

[hatedonmostly 5,000+ posts]

1/2" wood? idk dude, I think you should build it out of a garbage can //content.invisioncic.com/y282845/emoticons/nerd.gif.c6fa51ddf7ff75f1c0371fbc648f70ae.gif

 

[Qxxx4]

Aq's love 40 hz, throw in some bracing though if youre gonna use 1/2" wood

 

[CoilBurner]

You guys can stop worrying about 1/2" MDF. Ive used it on plenty of tight space builds and it works GREAT with oak dowels bracing every panel. Gains me over a cube in this situation so Im using it

Can anyone help me with the bend and length of the port for the 40 hz tune though, since I only have 18" depth and most likely need some L in the port

Im quite curious how you guys actually came out to the length AQ says, all the lengths I get in calcs vary from 24-27" port length

 

[d-REW 10+ year member]

1/2" mdf lol good luck i have mine hdc18 tripple baffeled and almost doubled all around with 3/4"

 

[CoilBurner]

Thats honestly nice thanks for sharing, but I do intend on 1/2"

heres a quote straight form AQ lol

"Your box should be free from air leaks and braced internally if the volume exceeds 2 cuft. Internal cross bracing is far more effective in making a rigid box than doubling the wood thickness. Doubling the wood thickness adds a great deal of weight to your vehicle, and the added wall stiffness is less than stiffness added by cross bracing. Try to cross the braces at the same point so that they add strength to each other."

Anyways

Id just like help with port length and bend please. all I need

 

[FurbiesAndBeans 10+ year member]

Everyone has told you the length needed. And you're still asking about it. Same with the thickness, people are telling you to use .75 but u keep ignoring them. Looks to me like you're the know it all and don't need our help.

 

[CoilBurner]

Yes 16" deep I get it. BUT I need to bend that and dont know where or for how long after to run it

I only have 18' depth, so a 16" deep port doesnt work,

Itll be 3.75" wide says, so would be to close to the back, I need to bend it

Would it still be only 16" long??

And MLStrass mentionned 6 cubes being to small for an HDC3?

 

[d-REW 10+ year member]

agreed sounds like he knows everything whys he asking and not taking our advise? if you dont wanna belive someone who has an aq hdc318 and built about 3 boxes for it then dont im not the one whos gonna have a shi t made box.

 

[d-REW 10+ year member]

to answer your question on the bend minus the port width from the back wall and bend it there so in your case it will be 3.75