Enclosure help for two 12" hdc4's

[myjaja 10+ year member]

Long story short, I had a guy building me a box at my cousins shop and he got fired from the shop. So im just left with some cut out wood for the box. Itll be 5.79 cu ft before port and sub and with wood thickness subtracted. The box is 33 x 17 x 22. The subs displacement are .414 each. How should I make the port for it? We have a long tube of a 4" pvc. I was thinking of having four 4" ports 14.23 inches long tuned to 37.

Would this be too little port area and too little room for the subs?

Click to read more...

 

[RAM_Designs 5,000+ posts]

That would be a higher tuning than 37hz. You need to take into consideration the space that the ports will take up and then determine the length based on the final net volume of the box. You just need to plug and chug a little to get something that will jive correctly.

 

[myjaja 10+ year member]

That would be a higher tuning than 37hz. You need to take into consideration the space that the ports will take up and then determine the length based on the final net volume of the box. You just need to plug and chug a little to get something that will jive correctly.

Really? Everytime I plugged those numbers in, I kept getting 37 hz. I guess I can be doing something wrong. lol

 

[RAM_Designs 5,000+ posts]

Really? Everytime I plugged those numbers in, I kept getting 37 hz. I guess I can be doing something wrong. lol

What volume are you using to find the needed port length?

 

[myjaja 10+ year member]

What volume are you using to find the needed port length?

I think I was doing it wrong.

Total box size is 5.79232 before subs and port and with would thickness subtracted. So adding subs in it will end up with a total of 4.965323 cu ft. With that, four 4 inch ports need to be as long as 16.915 inches for it to be at 37 hz. Did I do it correctly?

port area = (four 4's)16 x 4.96 = 79.36 square inches of port

I have no idea if thats correct. Im just trying to take over from box that was supposed to be built. lol but thats what I have so far ^^^^

 

[duanebro 10+ year member]

then subtract the volume the ports take up. then recalculate tuning... Oh and start with inside measurements for the box.

 

[myjaja 10+ year member]

then subtract the volume the ports take up. then recalculate tuning... Oh and start with inside measurements for the box.

Wow this is confusing.. lol

Now I got 4.188493 cu ft with all four 4 inch ports being as long as 20.584. Sound about right now?

Doing it once more and subtracting the added port area, Im getting about a good 2 cubes per sub