The Avalanche was the predecessor to the current Arsenal series. The Avalanches weigh about twice what the Arsenals do. The Avalanches were xbl2 technology licensed and the Arsenals use shorting rings instead(free technology). Damn sexy looking mother too. I've got one in my "too many drivers in the closet collection". I've read that they're a helluva HT sub driver as well.
The only knock I've ever read about the Avalanche series was that they didn't have a good high end.. say above 70hz , but being xbl2 they were low end monsters. They were significant because they liked small boxes and could really get down. They were sold direct via internet and offered very good value. This is starting to sound familiar ......