A couple days ago, I showed you the series of small speakers. It are tweeters. Tweeters don't have a low end.
The low end is important for that buzzin'-engine like sound.
Today, I was in the Subte (the Buenos Aires underground) and I got a call from Rafael, the project assistant. Mercado Libre, South America's eBay/Amazon helped me out. I just had to swap trains and in 20 minutes I had my 12" woofer.
Technology makes things a lot easier. :-)