There are three critical elements to a quality buzz roll. Each of these can be developed in the first weeks for a beginning percussionist, but are also worth revisiting by the most experienced professional. A quality buzz roll consists of individual buzzes that are thick, sustained, and consistent.
Each stroke in a quality buzz roll must be thick. A buzz roll with too much space between bounces doesn’t have the characteristic texture required to sound smooth and full. With the stick held securely between the index finger and thumb, the middle finger is the digit most responsible for controlling the degree of pressure to create a thick buzz stroke. Practice multiple buzz strokes with one hand at a single dynamic level, consistently evaluating the thickness of each buzz stroke and adjusting as necessary. Repeat the process with the other hand, then repeat at a variety of dynamic levels, both with repeated strokes in one hand and with alternating hands. The space between bounces will necessarily become wider as the volume increases, but the buzz of snares at that volume will fill in some of that additional space.
Each stroke within a quality buzz roll must be long—or at least long enough to fill the space between strokes by the opposite hand. Most younger percussion students try to roll too fast, choking off the length of each buzz stroke and working far too hard for too little benefit. To practice the length of your buzz stroke, set a metronome no faster than 60 bpm and play one buzz stroke per beat, striving to sustain the buzz (still with a thick texture) until the next stroke. A controlled, long buzz will allow for more options in the underlying rhythmic framework of your roll without sacrificing a full, smooth sound.
A quality buzz roll must consist of consistent strokes. It is necessary for each successive stroke within a buzz roll to be similar in thickness, length, volume, and rhythmic spacing for the roll itself to sound smooth. A series of quality buzz strokes that are long and thick, but vary from stroke to stroke, even to the slightest degree, will create a choppy buzz roll. Both by practicing individual buzz strokes with each hand and alternating strokes between hands, strive to make each stroke identical to the previous one at all times.
Again, while these concepts are suitable for beginning percussionists, they are worth incorporating in your practice routine, regardless your level of proficiency. The buzz roll always has room for improvement!