The high-pass filter is one of the most valuable processors in a mixer’s toolkit. Here's why:
- The low frequencies of many instruments (especially guitars) just get in the way of each other and don’t add much to the overall sound. If you roll off the low frequencies below 150 or 200Hz with the high-pass filter on instruments other than the kick and bass, the mix begins to clean up almost magically.
- Rolling off the low frequencies of a vocal mic can eliminate the rumble of trucks and machinery that you can’t hear because they're so low, yet muddy up the mix.
- Even rolling off the bass and drums at between 40 and 60Hz can sometimes make the mix a lot louder and punchier without affecting the low end much.