Subwoofer

If, for some strange reason, you've been kept under a rock, and don't know what a subwoofer is, then I strongly recommend www.dictionary.com.

But basically, it is the big bad bass speaker that makes your car shudder and rattles your floorboards. Even the ones kept under a rock have probably seen it on that show, Fat Pizza: "Subwoofer, oohh yeah!"

Sometimes things can be described by indicating their opposites... this is NOT what a subwoofer is about.

Starting a project is probably the hardest bit, so I went to cash converters to see what kind of subwoofer drivers they had, because there was no way in hell I was gonna buy a new one for over $100.

In the end, after drooling over some $200 Lightning drivers, I settled for an 12 inch Earthquake brand driver from the USA for $50. It is capable of 200W, which was pretty good at the time. Apologies for the bad picture quality.

For any loudspeaker to work, you need an amplifier. In the case of a subwoofer, you also need a separate filter, so that you're only feeding the low frequencies into the driver (otherwise it kills itself trying to scream like a soprano).

The low pass filter, or sub bass processor (left) was sold to me by Dick Smith Electronics as a kit.

I realised that I was to put the subwoofer in my room, which isn't exactly big. So 200W was going to be complete overkill (probably knock over the walls). Thus I decided on an amplifier with an output of about 40W (RMS) [right].

I ran into problems every now and then, but in the end, I finally had the electronics bit sorted out.

An extremely messy installation inside the sub... this picture was taken during a repair operation in 2006 when it mysteriously failed. Opening up the box and seeing how ruthless I was in mounting everything makes me wonder how stuff of mine actually keeps working...

By the way, the repair operation was successful, and the problems were due to loose connections wandering around and shorting into each other.

All loudspeakers need some sort of box to enhance the desired frequencies. In the case of subwoofers, this box has to be huge for good performance.

You've probably seen or have one of those small subwoofers no bigger than a couple lunch boxes stacked together right? Well no wonder they sound like crap...

To the left is my subwoofer box, with everything mounted already.

And to the right is the equalizer control panel, with adjustments for bass level, low pass filtering, frequency adjustments, and extra cut/boost to the bass.

It works great, and easily thunders over the neighbours who always listen to Kasey Chambers and gangster rap songs.

But after a while I thought that it looked kinda crap. Especially the equalizer panel. What the hell was I thinking, handwriting the words on with permanent marker?

And so was born the newly rejuvenated version. There's a diet coke can for scale, since I didn't have one for the first picture

It's just been painted gloss silver.

And perhaps a slightly "better" job to the equalizer panel, this time using a computer to type the words...

And also added an LED status indicator that flashes blue/red when the sub is on.

And a view of the driver behind black acoustic screening.

Notice the two vent holes in the bottom. That's to stop the box blowing up when the sound pressure is too high. Oh, also to improve the sound quality too.