[Shicks18]

Re: Blue prints of first sealed sub... need input!

Would porting this sub be a good idea? And tune it to around 18-19hz?? Thanks

 

[Mike P.]

The sub would benefit from a bigger box if going ported.

 

[Shicks18]

What would be good dimensions for a ported box?

 

[Mike P.]

9 cu.ft. tuned to 18 hz would give excellent low end extension.

 

[Shicks18]

Sweet. And just 1 long port would do the trick?

24x38x22

.75in material thickness
800 in ^3 bracing
290 in ^3 port volume (5" diameter x 14.78" length)
.25 driver volume
1
driver

net cubic feet = 8.862

Those dimensions seem okay?

 

[Mike P.]

What would you use for a 5" diameter port?

The modeling shows a 7 db advantage at 20 hz with the ported box. That's a big gain in the low end compared to the sealed using the same Bash 300 amp.

 

[Shicks18]

Ok looks like I need 6" diameter pvp pipe.

New calculations:

24 x 39 x 22
6" diameter pvp pipe x 22" long
.25 cu ft. driver
800 in^3 bracing
626 in^3 port volume

8.935 Net cubic feet.

How does all that look??

 

[Mike P.]

You got it! :T

 

[Shicks18]

SWEEEET! Im working up a sketch now will post when im done.

Looks like I will have the port coming through the very top of the cabinet. The driver will be front firing, towards the bottom of the cabinet, and the plate amp on the rear side.

That all sound okay?

 

[Mike P.]

Shouldn't be a problem as long as nothing gets dropped in the port.

 

[sub_crazy]

I would try to have the port down firing but then you would have to add some sort of legs to give the port clearance. I also read somewhere that a down firing port can also minimize port related noises.

Mike makes good point about watching that nothing get dropped down the port if you place it on top. If you are going to have it on top I would really recommend some sort of grill to protect from anything falling in.

 

[Mike P.]

There won't be any port related noises with this setup with an air speed that's maximum 16 m/s at 18 hz. As mentioned above, a grill over the port would be a good idea.

 

[Shicks18]

Good idea! Will do.

 

[Shicks18]

OOOK. Here is my finished blue print. Let me know what you experts think! I the baffling in the middle I had to cut in half or else it would come in contact with the pvc pipe. Suggestions are welcome, and needed!

Thanks!

edit: Grr, came up small let me fix it...

 

[Mike P.]

Looks good, you're done. Looking forward to your build thread!

 

[Shicks18]

is that enough internal bracing??

 

[Mike P.]

Yes.

 

[Shicks18]

Woo Hoo! Going to start working it on it shortly. My VERY last questions (I promise!):

1) How much fiberbglass insulation do you recommend?
2) What kind of glue do you recommend?
3) Is it okay to screw things together? (I never really noticed many screws on people's subs)

THANKS SO MUCH!!!

 

[Mike P.]

1. A couple inches thick glued to the walls of the enclosure. Another option would be egg crate foam sold as a mattress pad at WalMart for $15-$20. Much easier to work with.

2. I've always used a glue gun with hot glue to glue egg crate foam. Others have used 3M spray on adhesive. Make sure you reads the label on proper use, you have to spray both the cabinet wall and the insulation.

3. Wood glue and screws can be used. For screws use 15 inch long coarse thread drywall screws. You have to drill a pilot hole and countersink first so the MDF doesn't split. Do some test holes on a couple pieces of scrap MDF first until you get it right. The pilot hole needs to be a hair smaller then the shank of the screw.

 

[Ricci]

Looks like a subwoofer build to me...Pics of the work as it progresses are mandatory.