Help determine enclosure size for old Punch 15's

[Bret]

Model: RFP 1415
I have 2 of them.
The manual gives enclosure specs for sealed only. I want ported tuned to 30hz. I just need help figuring out the CF. I have used various calculators and keep coming up with nearly 10cf per sub so I must be doing something wrong. Would appreciate some help. Thank you.

https://www.rockfordfosgate.com/rftech/library/1996/5_subwoofers/rfp-1415_1815-ts.pdf

[Joe X]

Specs based on two 1415 drivers  tuned to  30Hz  and 400 W RMS total power.

 

8 net total with 36 square inches of total port area.

or

10  net total with 40 square inches of total port area.

 

 

[Bret]

Thanks Joe X! I was worried I was going to have to make a 20cf enclosure. 8 or 10 I can manage.

[Bret]

I built the box for these finally. It turned out 8.7 cf. Revisiting this thread to see what port recommendations I got from Joe x and I realized I don't really understand port area. I know what port volume to use according to torres calculator I downloaded. Torres shows my port area to be about 27ci using a 5.9" diameter id tube. Is port area just another way of expressing tube diameter? Is 5.9" a good diameter in my case? Thanks for any help.

[Joe X]

In your case a couple of 5" ports would give you a little above the 36 square inches of port area, unfortunately 5" pipe is not so easy to find.

[Bret]

Thanks Joe. I'm going to do a slot port instead.

[Bret]

Here she is. When I put the speakers in I noticed the surrounds were coming apart in several places. I just reconed these with oem parts. Guess I should have used some other surrounds.

[ckeeler11]

So what did you end up with on the port?

[Bret]

3" w x 12.75" h x 8" l

Hopefully tuned to 30hz. Ill see once I get some new surrounds and can play them.

 

[Bret]

Got the the surrounds last week and glued them on. Wired this up and am breaking it in. I'm really happy with the sound of it. I haven't cranked it up yet but at low volume it hits the lows like I was hoping. The tuning turned out to be what I was shooting for at 30hz. It will play below 25hz so I think I need to crank the subsonic filter up a bit. 

I tried painting it a few times and ended up covering it with foam core wrapped in vinyl. It worked OK but I'm totally disappointed with the 3m spray adhesive. I went through 2 cans ($20) and tried thin and thick applications and didn't get it to stick as well as I expected. I wouldn't use it again. Any spray or brush on adhesive recommendations?