Welcome to this follow-up to the Vibrato 101 tutorial. As I mentioned in that tutorial, I thought that timing and vibrato merits its very own tutorial, so here we go.
First of all, remember how we discussed the "smooth and even" vibrato in the previous tutorial, to avoid using the "EKG" vibrato? Having a smooth, and above all, even vibrato, means that the time between each micro bend and release are exactly the same, thus creating a uniform note value in relation to a specific tempo.
Let's say I am playing at 120bpm, then my vibrato might be a sixteenth note grouping in that tempo. Each peak of the vibrato would correspond to an eighth note, and each release to an off beat 8th note, together forming a 16th note pattern. I'm not using a metronome in the video, just stomping my foot. However, I urge you to practice this either with a metronome or a drum beat. This is also an excellent exercise to help get that smooth and even vibrato we so strive to have.
Try it out in any given tempo, with 8th notes, 16th notes and triplets. In the video I am also exemplifying using thirty-second notes, where you would count each micro bend peak as 16th notes. This makes it easier to keep the proper timing of your vibrato in that faster pace. Once you've mastered playing in time with your vibrato, move on to the next part which deals with "floating" over the beat, which is what REALLY constitutes a good vibrato.