Sonotube Subwoofer AKA Concresub

DIMIBU 1.0

This project came to be after discovering the Sonotube Subwoofer DIY pages in the internet.

Exited with the idea of putting together  a Subwoofer with good performance and low cost built by me, I started looking for some Sonotube "replacements", since I had never heard of this type of product here in Brazil. After several weeks of googling, I found a company called  DIMIBU , witch manufactures a product called Concretubo. The product is very similar to sontubes, and it's used for the same purpose.

After founding the tube, iI started to design my first DIY subwoofer. Looking for a good cost/benefit I came upon a Selenium driver. The 12SW2A . Simulated response done in WinISD beta whas very flat an deep, just what I was looking for.

Many questions appeared during the design phase of the project. Fortunatelly i found a great group of audio professional and enthusiast who were willing to help. The  Audio List Brazilian disscussion list, founded and moderated by Edu Silva, was very helpfull (and patient ) in answering all my doubts. Also the good folks at another discussion lins, the HI-FI oriented audiodicas , helped me a lot.

Here's the final project as given by WinIsd:

Driver: Selenium Bass 12SW2A
Vas : 197,0
Qts : 0,43
Fs : 23,00
SPL : 90,00
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Number of drivers : 1
Box type : Vented
Box size : 243,2 l
Tuning frequency : 21,55 Hz
Vent : 1 vent(s)
5,45 in length for each
4,02 in round
Generated with WinISD[0.44] freeware (C) Juha Hartikainen

After assembled, I was amazed by the results. I don't have many parameters to compare, but it performed better than a 12" JBL Subwoofer. It was the first time I had ever heard (or felt) frequencies that low. I'm feeding the sub with a Sansui A-60. The results are very satisfing. I now plann to aquire a stronger amplifier to push the sub. I just hope the walls hold togheter, 'cause since building the sub I had to seal the doors and windows with  auto-adhesive rubber strips :)

Here are some links to a few of the projects I used to help me plann mine:

http://www.quux.net/roo/diy/sonosub/
http://www.io.com/~patman/sunosub.html
http://www.hometheaterhifi.com/volume_6_3/diy-11-sonotube-subwoofer-september-99.html

And here are some pictures of the (un)finished Sub. It still lacks finishing. I didn't had a camera on the day of the actual assembling and was to eager to built it to wait :)

Concresub1_th.jpg (71706 bytes)
It's corner home.

Concresub2_th.jpg (71706 bytes)
Notice how it perfectly blends with the decor.  (not being married has it's advantages...)

Concresub3_th.jpg (71706 bytes)
Vent view, Speaker connectors and stands.
(inside the vent you can se the back of the driver)

Concresub4_th.jpg (71706 bytes)
Internal view (trough the vent), showing the driver basket and polyester batting material, to help reduce ressonance.

Concresub5_th.jpg (71706 bytes)
Another view of the bottom end.

Concresub6_th.jpg (71706 bytes)
Top end, with the Selenium 12" Driver (notice the great finishing....)

Concresub7_th.jpg (71706 bytes)
Size comparison. me x sub
(I'm 1,84 meters)

I'll update the pictures when gave the sub a finishing.