Explosions in the Sky is no longer on the fringe.

When you draw a paying college and university crowd of 3,000 to the Sound Academy, as the Austin-based instrumental quintet did on Friday night, to hear loosely sculptured sonic soundscapes that rely on anything but virtuosity, you’ve broken through.

The jury is still out on whether Explosions is deserving of that development, since the audience seemed to be tested by a fairly tedious performance as indicated by the din of chatter that continuously increased in volume as the 90-minute, encore-free show dragged on.

Visually, there wasn’t much to keep you riveted, unless your idea of showmanship was watching guitarist Munaf Rayani, bent at the waist, employ his axe in a shovelling motion or sink to his knees to adjust the pedals.

The music itself is also pretty unassuming: songs like “The Only Moment We Were Alone” from The Earth Is Not a Cold Place and “The Moon Is Down” blossoming from simple, sweetly pleasant, single-note melodies into epic three-guitar wall-of-sound assaults of furiously strummed chords strengthened on Friday with the addition of another unidentified body helping the four principals out on bass and guitar.

What keeps it interesting more often than not is the propulsive drumming of Chris Hrasky, whose imaginative rhythms both cut through the sonic wash and add a much-needed separate texture on which to focus. It’s music that translates well whenever it generates momentum; wordless soundtracks to non-existent films that are somewhat hypnotic, which is why it’s understandable that the Friday Night Lights film and TV franchises found them appealing enough to hire Explosions to write the scores and cue music.

But one could have just as easily stayed home, turned the volume up, and not missed much in the way of action. In fact, the most effective way to enjoy Explosions live is to close your eyes and let the music soak into your cranium.

The routine was rote: soft, delicate picking that introduced “Postcard From 1952,” a track from Explosions’ sixth and most-recent album, Take Care,Take Care,Take Care; then ramping up the energy and the volume with a note-for-note recitation of the recording and building to a frenetic din before calming things down again and immediately segueing into the next number.

It was the same story for any of the nine songs paraded before the plaid-and-denim multitude: impressive displays of dynamics during “Greet Death,” “Birth and Death of the Day,” “Catastrophe and the Cure” with occasional smatterings of applause and cheering, but overall, fairly monotonous.