There is a moment in this duo meeting of trumpeter Peter Evans and drummer Mike Pride that is brief yet speaks keenly to their partnership. It comes 4:12 into the 7:09-length of fifth track "Substance 5": Evans unfurls a technically challenging figure alternating four and five notes, under which Pride both punctuates and parries. It lasts less than a minute before Evans opens it up into a muted fanfare, Pride becoming only slightly more insistent. It is callow to think these things happen spontaneously within free improvisation; spontaneity is hardly mutually exclusive with preparation and foundation.

A Window, Basically is a fascinating bridge between Evans's solo performance and the power trio Pulverize The Sound with Evans, Pride and bassist Tim Dahl, in existence for over a decade. But it is not as simple as adding or removing elements as if these players are part of some musical Jenga set. Making the process of understanding even hairier is that the album is not, as one would imagine, a single afternoon's improv session but, rather, a collection of interactions across a nearly-three-year period at Pride's home studio.

The seven "Substance" tracks, all lettered apart from the aforementioned "Substance 5", are not in alphabetical order and there is no indication of when each was recorded. Still, a narrative arc of sorts emerges as the pair move from an initial foray, "Substance X", implying a straight-ahead rejoinder to Interstellar Space, to Evans incorporating increasingly technical flourishes, which Pride limns expertly, on the following "Substance T" to the longest piece, "Substance Z", whose duration allows for the most dynamic range but also reminds a listener that Evans is a fearlessly motivic player. Prior to "Substance 5" is "Substance M", pushing abstraction and angularity further than what had come before and trumpet like a Pointillist's brush, while "Substance Q" on the other side is fully articulated at only 76 seconds.

The closing piece, "Substance P", is the outlier in Evans's use of piccolo trumpet and Pride completely eschewing any timekeeping in lieu of scraped cymbals and gong-like effects (or maybe just a gong?), five-plus-minutes of sculpted soundscape and a compelling bookend to the opener.