here's something I do Dan, but I can't testify to the overall effectiveness for all systems. It seems to help it translate better to the stystems I play through

First of all, the equipment on the market is widely different in the frequency ranges they handle. My thinking is that you can only control what you can hear, and you can only hear the ranges supported by your mixing monitors. So the first thing I do is take note of my system's range from high to low. (This is usually on the speakers or in the manual)

Then when I mix, I completely remove any frequencies above and below the range of my monitors. In other words, I'm only assigning frequencies that I can hear within the range of my speakers.

Then, if I have 5 instruments, I divide the total range of my monitors by 5, and give each instrument the full 20% of range (with no overlap)
Here is a chart that reccommends frequency ranges for many instruments



For example, the instruments might be EQed as follows:
(not a hard rule, just one of many possible examples)

(100% = highest frequency my monitors can address)
81-100%= organ
61-80% = guitar
41-60% = tenor sax
21-40% = drums
0-20% = bass
(0 = lowest frequency my monitors can address)

for each instrument, completely remove the frequencies above and below the target range, then use the EQ sliders to adjust the tone using the remaining frequencies


This approach should accomplish 2 things:
1) eliminate muddiness caused by instruments competing for the same frequencies
2) removes all extreme frequencies that you can't hear, can't control and which are most likely to be problematic on a wide variety of other listening devices.

https://www.dropbox.com/sh/ey71h8ep047758h/AAC12jNM0Hz9Q8zsh5iDeqNHa?dl=0