Help Designing Box For HDS312

[B1GR3DDD]

Making a new post specifically about designing a box for this sub. So I want to make a center port design, if you saw other posts from me, for two HDS312's. First thing I did was take a look at the charts for a single sub in WIN ISD.

This is for one HDS312 in a 2.35 ft.^3 box tuned to 34 Htz

I'm no expert on charts, so give me some feedback on what you think of the results of that.

Next up I put a box together quickly in SketchUp just to see if I was getting the design right. WIN ISD gave me 24.2 inches for port length, so that's what I'm using for now.

I measured the length of the port from the center, following it down around the corners.

How does it look? Is there anywhere I screwed up in calculations that needs to be fixed (probably)?

Click to read more...

 

[Jeffdachef 5,000+ posts]

Winisd part is fine. The tuning and design is way off. With those dimensions, you only have 4.66 cubes gross. Definitely not enough airspace after accounting in port and sub displacement. After displacement, getting a tuning low enough will put you in the 3 cubic feet range because the smaller the box is, the longer the port needs to be to get lower tuning. The port displacement can even make it so that you can never reach a certain tuning if your box is too small. You also want a center divider if possible.

Use torres box calculator and you'll get a sense of how much space ports actually take up.

 

[B1GR3DDD]

Win ISD gave me the length for the port, I was following that

 

[CSCStang]

Use Torres like Jeff said. The box is too small. They need roughly 2.5 net cubes (not gross) to really shine.

 

[keep_hope_alive Premium Member]

And tuning won't be what you think because port area changes, tuning will be higher without a center divider in the port.

Sent from my SM-G900V using Tapatalk

 

[Jeffdachef 5,000+ posts]

Win ISD gave me the length for the port, I was following that

Winisd assumes you already know how much space is left after accounting in for the space the port and sub takes up. Thing is, you have not done so at all. Hence winisd is a poor choice to go off of if you are new to this.

Need to draw a clear line between Gross cubic feet and Net cubic feet.

The bigger and longer the port, the more space it takes up and the less overall USABLE NET cubic feet of airspace you will have

Again download torres box calculator

 

[B1GR3DDD]

Didn't take that into account. Will definitely take a look at torres. But open question for whoever. Does anyone think an aeroport would be a good option? A 4 inch aero would give me enough port area, along with not consume tons of usable airspace like a slot port would. My max dimensions for this box is 37x16x19, so I have around 5.2ft^3 to work with, and with an aero port and some bracing, I could probably keep the net feet cubed around 4.7-5 ft^3

 

[DaytonLax14 10+ year member]

Here's a box design someone used on another forum

Box specs:

http://s29.postimg.org/611h7gfon/hds.jpg]

Picture:

http://i1217.photobucket.com/albums/dd393/JoeDurkham/SFPFnoturnTshaped_zps723b7804.jpg]

 

[B1GR3DDD]

I think I'm going to opt for an Aeroport to cut down on some displacement. I'm going to need around 40 inches^2 of port area, so I'm a little confused on what size to get. I'm looking at around 4.7ft^3 after displacement. Any thoughts?

 

[DaytonLax14 10+ year member]

I think I'm going to opt for an Aeroport to cut down on some displacement. I'm going to need around 40 inches^2 of port area, so I'm a little confused on what size to get. I'm looking at around 4.7ft^3 after displacement. Any thoughts?

Where did you get the figure for 40 inches of port area?

I'd do 2 6" aeros if I were you. About 18" long

 

[Jeffdachef 5,000+ posts]

I think I'm going to opt for an Aeroport to cut down on some displacement. I'm going to need around 40 inches^2 of port area, so I'm a little confused on what size to get. I'm looking at around 4.7ft^3 after displacement. Any thoughts?

i'll design one for you if you want, Just let me know the MAX dimensions you can fit. Just to warn you ahead of time, you'll need at least 5.5 to 6 cubic feet gross to start off with if you want to achieve a 4.5 net box.

 

[B1GR3DDD]

Where did you get the figure for 40 inches of port area?
I'd do 2 6" aeros if I were you. About 18" long

I've read some places that a slot port is recommended to have around 12"-16" of port area per cube and aero's to have around 6"-8" per cube. With just my box dimensions, woofer displacement, and wood thickness, I get 5.03ft^3, so 5*8= 40 inches. I don't know if this is right, just following what I read.

And when you say 18" long, is that PER aero or total? My box has a max depth of 19", so I'd imagine an 18" long aero wouldn't be too happy that close. Could be wrong

 

[B1GR3DDD]

i'll design one for you if you want, Just let me know the MAX dimensions you can fit. Just to warn you ahead of time, you'll need at least 5.5 to 6 cubic feet gross to start off with if you want to achieve a 4.5 net box.

I have 37" W, 16" H, and 19" D. Not the roomiest situation but its all I got.

 

[Jeffdachef 5,000+ posts]

I have 37" W, 16" H, and 19" D. Not the roomiest situation but its all I got.

Yeah you are not going to have anything higher than 4.4 cubes total and thats without any bracing and that is very little port area, you'll definitely want to get 4 inch pvc pipes and heat/flare them out. We want the ports to fire the same way as the subs since this is in a trunk car. If you want to use two 6 inch or one 8 inch port, it will give you more port area but will decrease your cubic feet even more and require you to do side port because your depth is not long enough.

 

[B1GR3DDD]

This doesn't look too good for me. I'd like to keep the box over 4ft^3 but it's looking like that's almost impossible while keeping the port area up.