If I want to change up the sound, the source remains the same, but amplification changes with the choice of speakers I’m listening to.Same thing than for amplifier and speakers ,it is very easy to buy a "relatively good source" nowadays...
Creating passive material treatment for a room and especially active mechanical controls to complement and enhance it is way more difficult...
People are hypnotized by pricing gear product, less so by acoustic and psychoacoustic fact....
Under 20 feet room space only acoustic matter to reach heaven with almost any " relatively good for basic gear "...
Why 20 feet?
Because it is easy to control TIMING under some acoustic treshold and use it for your benefit...
A very big room is more costly to control....
My room control 13 feet square cost me nothing to be controlled...