Best practice varies based on the specific use case, but generally you don’t want to modify sound any more than you have to. The more you modify, the more it has the potential to distort the sound depending on the quality of the particular amplifier and other components. It can get complicated, especially with hardware/analog EQs because of physical quality of the wiring, connections, and components. So, in general, it’s best to leave most things at 0db and change only the things you want to change. However, there are exceptions. Like if you want to change all but one of the frequencies by -4db, you’re better off changing the main amp by -4db and increasing just the one you didn’t want changing by 4db this the EQ is only modifying a small amount of frequency and the rest is passthrough. And generally the main amp is going to have less distortion than the EQ.

That being said, this is talking about cases where your tolerance for distortion is extremely low or you have a really shitty EQ, in which case it’s probably better to just throw it out and forget the whole thing 🤣. Because most people aren’t going to notice the difference of using the EQ for amplification or the main, even if they aren’t the best quality.

So, if you really are as picky about stuff that doesn’t matter much, but just want things to be as perfect as possible, like me, balance towards 0 as much as possible using both the EQ and the main. Otherwise, do whatever, probably no one will know the difference.

Also, I know the math isn’t exactly right for the -4 and +4, but there are other things you need to know to get it perfect anyway for one inline -4 to equal another inline +4. But it’s close enough…