[2][3] On the albums Concept and Caldera, Mathews played his second instrument, the bass clarinet, in order to form a woodwind trio with Cole on saxophone.
[2] Free jazz critic John Sharpe praised the group's collaboration, noting that Mathews' "bowing segues into a spirited conversation between Rivers' soprano wail and Cole's intertwining tenor".
[3] The trio with Mathews and Cole was described by Orlando Weekly writer Matt Gorney as "an almost vaudevillian, recombinant band offering free bop, out funk, ballads, ruminant impressionism and, of course, the fire.
"[4] Mathews was known to attend concerts by Rivers' original trio (with Dave Holland on bass and Barry Altschul on drums) when they performed.
[7] Three years later, Mathews joined resident guitarist Mary Halvorson at the Atlantic Center for the Arts along with saxophonist Dan Jordan, trombonist Keith Oshiro, saxophonist David Pate, trumpeter Tom Parmerter and drummer Tomas Fujiwara.