I feel this is a skill set that is far too often overlooked. We spends hours, days, months, and years developing rhythmic independence, sometimes to the point of levity, but often don’t take the time to think about developing that same level of independence in terms of dynamic balance. That’s one of the things (among many others) that makes guys like Peter Erskine so appealing. You could put Peter in a studio with nothing but a pair of overheads, and the balance between each of the components of the kit would be absolutely perfect, as though an engineer had mixed it and said, “I’m just gonna’ pull the ride cymbal up by one dB”. It was that idea that led me to use this analogy as an exercise with a lot of my students that I’d also like to encourage you to try.
Picture each of your limbs as a fader on a mixing console. See if you can control the dynamics of each limb individually without affecting the others. Start with “the AC/DC” or “Billie Jean” beat. Play everything at a relaxed forte. Strong and confident, but not over the top. Now, take your hi-hat down to pianissimo, crescendo to fortissimo, and decrescendo back down to pianissimo - or in other words pull the fader all the way down, push it all the way up, and pull it back down again - all without letting your bass drum or snare drum change in dynamic level. Then try the same thing with your left hand, and right foot.
This concept can be applied to any style of music. As we focus on a lot of jazz here on the blog, consider the same exercise while playing out of Syncopation or The Art of Bop Drumming. It adds additional layers of complexity as the left foot is now involved, and there is also a changing variable in the left hand. For example, feather the bass drum, play the hi-hat at forte, sight-read the left hand part at mezzo forte, and take your right hand through the fader process.
You will probably find that certain pairs of limbs are locked dynamically and follow each other, the same way your right hand and right foot always wanted to play at the same time when you first learned rhythmic independence. Practicing this will not only physically separate your limbs in terms of dynamics, but it will also fine-tune your ear and add a new level of detail to your playing as you draw your focus to each individual limb and how they sound together.