This fretted acoustic bass is played in cello position. Two special features: 1) The neck and fretboard are oddly angled. This is to make it so that a typical bass player’s plucking motion propels the string in the direction that activates the soundboard most effectively. 2) The soundboard is unusually light and non-rigid. (The strings are anchored in a way that minimizes pressure, so the soundboard doesn’t collapse.) These features improve the volume, and they contribute to a heavy, thumpy attack, good for a rhythmic bass sound. The fact that this somewhat crudely made bass sounds pretty good makes me think maybe these peculiar features were good ideas.
In the sound clip, the Cubist Bass is joined by an electric guitar and percussion.