12" Sonotube Subwoofer

Introduction
Design
Results
Future Plans

My original subwoofer  was my first effort in speakerbuilding and I felt I could improve on the design. I decided on a passive radiator design to maximize low frequency response. Since it was for the Home Theater I wanted the most rumble and house shaking I could get. On the other hand I didn't want to make too many sacrifices  in the accuracy of the response. A full size cabinet with a passive radiator seemed the best compromise.

SInce I'd already obtained a subwoofer and a plate amp for my sonosub project, the design was simplified to sizing the cabinet for the woofer and the passive radiator. I bought  a 15" passive radiator from Adire Audio. I decided that size was no object in my pursuit for low frequency. With a  8.235 Ft^3 cabinet the box tuning  frequency is17.88 Hz. Here's a plot of the predicted frequency response. Once again I used WinISD to model the cabinet using a ACI SV-12 driver.  ACI doesn't seem to sell drivers anymore, having concentrated on conplete speaker systems, so future designs will not include the same driver. Here's the outside dimensions of the cabinet and a layout of the panels needed from a 4'x8' sheet of 3/4" MDF.

.  Since my amplifier only has a Dolby Digital 5.1 output I also needed an amplifier. ACI had a package deal so I got a PSA-1 amplifier with the speaker. 

I'm fairly happy with this design. It's much cleaner than any commercial subwoofer in this price range (about $400). Its so clean that its deceiving how loud it is.

I'd really like to build another subwoofer so I have a pair on each side of the TV. I'm looking at the Adire Audio  Shiva Mk III for the driver.