I'm a complete beginner when it comes to mastering. But I think it's a common practise to magnify the sound of an instrument in its particular range of harmonics, and if two instruments are close, like a bass drum and a bass guitar (panoramics left apart), each one will see its harmonics magnified in a refined particular frequency range that will be different from its close neighbour, so that they can sound distincly even if played together.

I was wondering if another way to achieve this goal could be to magnify the harmonics in a more « mathematical » manner, let's say, magnifying the bass drum harmonics frequencies if they are even, and the bass guitar ones if they are odd?

Do you think this could be effective, or is it way too much theoretical and unadapted?

Thanks in advance,

Cyrill