Before "Heat," Michael Mann directed "L.A. Takedown" (1989), a TV movie with an almost identical plot to the 90s classic, but with a much smaller budget. Although "L.A. Takedown" is inferior to its definitive 1995 version, the shootout in downtown Los Angeles is very well done and demonstrates Michael Mann's great skill in filming action scenes.
The scene in Collateral when Tom Cruise shoots the two meth heads in the alley is a masterclass in realistic gunfire sound design. Michael Mann chose to shoot the scene in a location in downtown L.A. that had perfect natural acoustics for a gunshot—a concrete canyon situated between a tall apartment building and a large above‑ground parking lot. When the blank rounds were fired, the sound waves bounced off the parallel concrete walls, producing a deafening, reverberating blast that hangs in the air.
According to sound designer Elliott Koretz, the gunshot audio captured on set was so powerful Michael Mann told him to leave it mostly untouched. Koretz said he only lightly enhanced the impact of the shots; the final mix still uses that same raw production echo.