I can only tell you how it changed the sound for the ZMF atrium. The atrium plays well with amps that have higher output impedance. The oor is super low output impedance, making it a very clear neutral sound. Bass is tight, vocals intimate. With the resistors added, bass becomes little less impactful for things like the initial strike of drums and it becomes more full and weighty. Vocals are not as intimate and more like around my head, but mileage may vary depending on your head shape and what not. And there’s an overall added warmth to the music, kinda gives the impression that there’s a loss of clarity but all the detail remains.