"Articulate" usually refers to a clear & pronounced tone, with no or very little overdrive, and abundant clarity. The easiest way to achieve an "articulate" tone is to combine a Solid-State preamp with a high-wattage power-amp (for more headroom) and smaller speaker cones (5", 8", or 10" woofers). From the instrument standpoint, Modulus basses are the quintessential "articulate" bass, having extreme clarity and piano-like consistency from string-to-string due to their graphite construction.
Articulation also refers to:
1) strong mids, especially upper mids
2) clearly defined tones
(Reflective artist: Chris Squire) 3) Can also refer to strong highs
4) When concerning speaker cabinets, generally refers to smaller cones (5", 8", or 10"), possibly with the inclusion of a horn for more high-end.
5) When concerning power amps, generally refers to generous headroom.