For myself, I'd divide bass sound into the categories below. Vintage : 1950's - 70's. Tubby, thumping tone, lots of low-mids and not much high-end or low-lows. This was probably a function of the equipment available at the time (Fender, Gibson, Ampeg, Marshall, etc..) rather than any preferences. Modern : Starting in the 80's. The scooped sound. I'd peg it at the introduction of cabs with tweeters (SWR). The modern sound didn't supplant the vintage sound, it's just another choice (edit: obviously some day the "modern" scooped sound will be vintage...) Hi-Fi : Starting in the late 90's (?). Full range, or "Flat", from low B upwards. Full range meaning little coloration is added to the sound by by the equipment. Acme, Accugroove and EA come to mind.