David's Tip of the Day: Different Types of Tremolo and Vibrato - Part 14, Vibrato & Tremolo Mixture (Dynamics)

The vibrato needs a bit of airflow to activate all of its moving parts, so it doesn't work at very low volumes. For this reason, practicing going from a low-volume tremolo into a vibrato is time well spent. The practice is straight forward, start playing a note as softly as possible, using a tremolo of course, and as the volume increases enough to use the vibrato, switch to a vibrato as smoothly as you can (not allowing the vibrato to kick start and start swing hard and fast... the goal is a smooth transition). Once you've reached full-volume, reverse the process, bringing your volume down, changing from a vibrato to a tremolo smoothly.