“Fair enough” I hear you say “but can you give us some examples?”  I thought you would never ask.  Near the beginning of the title track of Leonard Cohen’s You Want It Darker there is a simple drumbeat overlaid with a bass guitar.  With the EQs in place, there was a percussive thump to the leading edge of the drumbeat that was lessened when the EQs were removed.  Also, with EQs, the drumbeat held its own behind the bass.  Without EQs, it seemed to hide in the bass guitar’s shadow.  This, of course, is just a small detail from a song which features a male choir and a huge, deep close- mic’d vocal from Cohen.  Taken overall, the separation between the instruments (drumbeats and bass), choir, and Cohen’s vocals (quite obviously recorded in a different acoustic space) were more evident and the whole thing just sounded better.”

Read more here: https://www.hifipig.com/stack-audio-auva-eq-equipment-isolators/