I’ve noticed that many audio enthusiasts frequently upgrade their audio gear, never quite satisfied with the sound of their systems. They replace one perfectly good DAC with another, upgrade power amps, experiment with tube gear and tube rolling (the practice of replacing one tube with another of the same type, then attempting to judge by ear which sounds better), and even replace signal and power wires, hoping for the leap in clarity and realism they’ve read about in hi-fi magazines but never experienced. However, very few audiophiles consider the one aspect of audio quality that matters more than anything but the music source: the acoustics of their own listening rooms. Curtains and carpet are not effective acoustic treatment because they absorb only high frequencies, and a proper measurement will quickly prove that.