Home Theater Forum and Systems banner
1 - 7 of 7 Posts

177 Posts
Discussion Starter · #1 ·
I just finished building my two sonotubes out of the C12.2s I ordered a while ago. I've gotta say I love these 12s. It really makes me want to try some 15s or 18s :)

The finish is koana brown from Home Depot with 3 coats of sprayed on poly over it. No build pics cause I accidental formated my memory card. Construction was pretty straight forward. A friend a church had two 36" pieces of sonotube (16" dia) left over from a construction job so I used them. Slightly smaller than I'd like but I can't complain about free. The end caps are 2 pieces of 3/4" mdf, sanded down with 150 grit, then a coat of 50/50 water/titebond III, sanded, then another coat of 75/25 water/titebond III and sanded again with 150 grit before painting. The baseplate is built the same way and the legs are 6" long 1 1/4 oak dowels. The covering is some sort of pleather from hobby lobby that matches our couches fairly well to improve wife appeal. The pleather is kept on with 2" x 12" strips of industrial velcro on the back so the look from all around is pretty clean. None of the "barber pole" look of the sonotube shows through like I've seen on some fabrics. Although on one tube you can see a line where the fabric is folded over.

The speaker wire will be hidden MUCH better later, still working on positioning right now.
o-audio 500w plate amp
HPF set to 20hz
Speakers are to present a 4 ohm load to the amp.

1 Tube- 3.718 Cf
20.5" x 4" round port 1/2" flare = 19.5hz tune

Both tubes:
Projected F3 - 22hz
Projected F6 - 19.5hz
Projected SPL 30hz - 117db
Projected SPL 20hz - 112db

Measured spl so far 120db @30hz w/ room gain and spl meter correction.

Fun facts:
Can vibrate plates out of the cabinets
Very little port noise for test tones @ 20hz and it is inaudible during movies
Found the resonant frequency of the fireplace, entertainment center and fan on its first try.
Shakes the furniture in the master bedroom during movies


177 Posts
Discussion Starter · #3 ·
Nice tubes! I can't find any info on the C12.2. I take it they are discontinued?
Yep, got them on clearance from AE. At the time it was all the economy and wife would approve for a sub budget :)

Here are the stats:
Fs: 21.5Hz
Qts: .38
Qms: 4.5
Qes: .415
Re: 6.6ohm (in series)
Bl: 18.25Tm
Z: 8ohm (in series)
Le: 2.0mH
Vas: 154L
Mms: 155g
Cms: .35mm/N
Sd: 553sqcm
Xmax: 16mm
Vd: 1.78L
Suggested Power: 150-350W

For $75 each I have been incredibly happy with them. Haven't never had a "real" sub before they were a great starter build. Next on the list is a few 18s for an IB :dumbcrazy:

I think I've got REW working with my laptops built in sound card so I hope to have some graphs posted soon.
1 - 7 of 7 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.