Imagine a situation where something you’re working on is simply too fast for you to play at the moment. How might you address that?
I would say that there are two main approaches to consider.
Approach One: “Pick a tempo that is slow enough where you can play all the notes comfortably. Then gradually work the tempo up.” This is the way most students know and I would say it’s a good solid approach. The main problems are: (1) students may not always follow through all the way to the final tempo and, especially, (2) that the kinds of muscle memory and reflexes involved in playing fast are quite different, so you often have a”brick wall” phenomena, where you are stuck at a certain place in terms of speed.
Approach Two says: “Play a small chunk of the line, passage or piece but at or near the tempo, within reason and comfortable, but as fast as is easy for you. Pick a small enough unit that you can handle it. It might even be just two notes, the idea is you want be able to play those notes EFFORTLESSLY, in order to program SUCCESS in your daily practice, . This success is at the speed you will actually be playing so it makes more sense to your body.
I think without a doubt that both are very important and how much one shoud do of each will depend. I say all of this from my own experiences studying various instruments with excellent teachers, especially cello, piano and drums. I can tell you that I always did a lot of slow practice, both in reading music, at the piano and on my bass and cello, but also, and especially, in the creation of improvised lines, and it was later that I learned more about the second approach.
So, the two ways I’m talking about are Slow Practice and Chunking/Impulse Practice. Try both in your practice. Invert the order, that is don’t always start with the slow practice, though that’s never a bad idea.
In both situations, you’ve got to monitor yourself and make sure that you are really hearing what you are playing, both in scales, patterns and etudes, and in improvisation. In other words use your ear!