Common misconception, foam will do nothing to capture mid to lower frequencies. Those square black panels guitar center sells? Absolute hogwash shit. All that does is maybe suck up a tiny amount of the only good high frequencies you have.

No, true room treatment is bass traps, 705 panels, large ceiling hung diffusion panels etc.

6 figures easily with this stuff. Which is why most places do not bother even though terrible sounding rooms create fatigue and are awful to be in. A lot like modern houses. They sound horrid inside due to giant square boxes, no wood surfaces (drywall sounds awful), steel beams instead of wood, not even any popcorn ceiling to help a little with diffusion.

I always wanted to do acoustic education/installation for folks, but its too costly, its not somethibg they can “see” results of so its a dead business unless you only do mega churches. Really a shame, as its such an important thing psychologically

At some point you’re just building a better room