Single Stroke Roll Progress
I have struggled significantly with bringing my single stroke roll speed above 16th notes at 175 BPM. This morning, I was able to hold 16th notes at 185 BPM. This was a result of consistent, daily work for many months (about 5 months). I found that my speed really leveled off for most of that time.
A little sloppy at the end, but I'm happy with it! Also, I was only able to hold it for about 25 seconds.
What Didn't Work
I tried holding 170 BPM and 175 BPM for long periods of time (5+ minutes) for several weeks. That helped with consistency, but did not increase maximum speed. I also tried practicing left hand lead. This didn't seem to help, either. I tried practicing both strict wrist and strict finger motions, too. I was very consistent with practice (6+ days per week). Some days, I was spending upwards of 40 minutes, but usually it was closer to 15 minutes.
After 4 months without progress with the above methods, I decided to bump the metronome up and go for short bursts. This was groups of 16 per hand (as 8ths) until I reached a max speed. Then I would drop to groups of 8, reach a top speed, then drop to groups of 4. Doing this once or twice a day (it takes about 5 minutes after getting warmed up), I found that after reaching top speed as groups of 4, I could drop down and hold 16ths at 180 BPM for somewhat longer periods of time (maybe 15 or 20 seconds). In fact, this happened the first time I tried practicing this way. So, I decided to keep working this strategy, and now I seem to have made a pretty decent breakthrough.
I don't do any more holds for extended periods of time at lower tempos. And, I find that I can only work the very high tempos for a few minutes a day, before things start to fall apart. I do take breaks and work on other things, then come back and do the drill again, if I have time. So, this can be done several times a day, but I'm not sure what kind of impact this has on speed development.
I'm going to keep practicing this way for the next several months, and hopefully I can reach 200 BPM as 16th notes sometime this year.