My Subwoofer Project

I decided that I needed to add a subwoofer to my home theater. Rocket launches, jet engines, gunshots, and explosions just did not have enough punch. Since I wanted a high quality subwoofer but did not want to spend much, I decided to build it myself. After seaching posts on the Home Theater Forum, Home Theater Talk, and reading various pages by others who built subwoofers, I decided to use the Adire Audio Shiva driver in a sealed enclosure. For the amplifier, I got a couple of free samples of the National Semiconducter LM3886 high power audio amplifer.

The National LM3886 is designed to used as a high power audio amplifier. With the right power supply and heat sink, it can deliver over 75 watts into an 8 ohm load. Since the Shiva driver has dual voice coils, I used two LM3886 amplifer chips. From a scrap pile at work I was able to find power transformers, large electrolytic caps, and a case with power input filter, fuse, and switch. I was able to buy a very large heat sink at a good price on Ebay.

For the subwoofer enclosure, I used 3/4" thick MDF. The enclosure plans are from the Shiva application note provided by Adire Audio. The outside dimensions are 18" wide, 18" deep, and 22" high. It is a sealed design and internally braced.

More info on the Amplifier

More info on the Speaker