Hmmm. Interesting. The internal speaker acts like a normal speaker until you plug in external speakers to the speaker jack on the back, when it switches to subwoofer mode. I think the external speakers will get the full range of sound, but I'm not sure. My external speakers sound like crap without the bass from the subwoofer because they aren't very good at reproducing the low frequencies. If you plug speakers or headphones into the headphone jack on the front of the tower, then the speaker/subwoofer unti shuts off.
Did you check to make sure that the subwoofer control knob on the back of the case didn't get turned down? It's near the top of the case, right below the built-in monitor jack. That would be the first think I would check.
And I'm wondering why this thread got moved to the peripherals forum? The subwoofer on the 6400 is built-in to the computer and there's no way to remove it without ripping the case apart. It doesn't qualify as a peripheral in my mind. (Just me ranting a bit. Feel free to ignore.)
Hope this helps,
Dave C.
[This message has been edited by CyberDave (edited 08-14-2000).]