Bass Amps and Tweeters

Do bass amps really need tweeters?

Tweeters have become more & more common in bass amp combos and speaker cabinets in recent years, as I'm sure you've noticed. Do you need them?

There are several cases and sets of circumstances where I think tweeters are entirely unnecessary.
 - If you're the kind of player who just sits in the pocket and plays basic lines, nice & fat & low, never slapping or popping or 'spanking the plank'. You likely even use flatwound strings.
 - If you play fretless, in which case also you might even use flatwounds which have very few upper harmonics. Tweeters would tend to over-emphasize the 'buzz' of a fretless, resulting in a harsh rasp.
 - If you play 'oldies' & (very) classic rock (Cream, Mountain, James Gang...)

But, if you want to emulate Marcus Miller or Victor Wooten on a fretted instrument, you're going to want that tweeter. Modern round-wound bass strings have a very rich harmonic content in their sound, and for those of you who like to utilize that, a tweeter is just the thing to make those harmonics really pop out and sing.

The types of tweeters offered in bass amp systems these days vary from piezoelectric types, to dynamic horns, to dome tweeters, to aluminum cones.  Piezos are my least favorite, because they roll off at a rather high frequency, letting only the very highest overtones through. They also tend (to my ears) to sound a little 'harsh'. Dome tweeters and horns (which are basically dome tweeters with horn lenses) sound better, but unless the dome is of a fairly large diameter, say, 2" or more, they also tend to roll off pretty far up there. I like the aluminum cone tweeters that Hartke uses. Their frequency response seems to extend a little lower than the other types, thus bringing out the upper-midrange a bit more. And let's face it, basses don't really put out much high treble (>12 KHz). Something that kicks in at around 1KHz and goes upward from there to 15 KHz is about ideal.

But hey, I'm a fretless player, and I keep the tweeter in my Behringer combo unplugged entirely, because those 10" aluminum-coned speakers seem to give me all the highs I want, and then some.

But if were a 'plank-spanker' and wanted a lot of upper harmonics, I might build up a speaker rig something like what Stanley Clarke used to use on stage.  He had two 15" Karlson enclosures one atop the other on their sides, with the slots facing opposite ways, and topped with a strange-looking cabinet containing about eight of those 4" 'hot-spot-monitor' drivers mounted on a plexiglas 'dome' for good dispersion of the high frequencies.  He also bi-amped that system, and it sounded awesome!   I wish I could find a photo of that rig to show you...