Don't understand why people talk about flats as being dull. Maybe it's my amp and cab combination (Ampeg PF-50T with SVT-212AV). Or maybe it's my bass (Fender Aerodyne). Or maybe it's the particular flats I'm using (D'Addario Chromes). But I have no issue getting any area of the frequency range. I've even used it to record some heavier tracks lately where I was looking for that modern metal "barbed wire" sound.
My fingers love D'Addario light gauge chromes.