Weathering is the dark coloration over the natural metallic surface of the aluminum, to give it the appearance of being a "well used". A high bass speaker is a speaker able to produce the sound from the saber with just a little more vibrato than the standard speaker. Typically they are 2 watt speakers.
A weathered finish, you can get as an option on a standard saber order from SaberForge. The high bass speaker is not an option from the main site, or Etsy, but the Saberforge Custom shop could do something like that. They can also do custom finishes in a variety of colors, crystal chambers, electronics that differ from standard offerings, and can probably work with you on other ideas you might have. Of course, going this route is more expensive, but if you crave something truly unique, it is the way to go.