There are two types of Vibration that I am aware of:
Verbal/Spoken vibration
This is commonly used in Enochian magic, Golden Dawn magic, etc When you vibrate divine names, you are adding your emotion poured into it, and you concentrate on a long slow format of the name:
Th-awww-thth for Thoth for example. Or R-a-a-a-a, really as long as your breath can be exhaled, you are speaking through the exhale in a sine wave form.
Mental Vibration
This is the ability to control chaotic states of mind, and send/receive thought. Students in the air grade often get overwhekmed because thoughts are out of control, so control them.
From Raymond Buckland for a Vibration Exercise (Book of Spirit Communications by Raymond Buckland):
Vibrating names go deeper than just extending a vocal/mental exclamation of the word itself. When you vibrate a word of power, a divine name, the name of an entity, you should actually feel a buildup of power within and without yourself.
When I first started getting into more traditional magic, this feeling was hard to perceive. Now, even when I do a simple ritual like the LBRP I can feel the tingle of power within myself, but also into the space of the pentagrams when I charge them with the divine names. I feel the visualizations themselves vibrate with the holy names, and exude around me. Same things with the calling of the angels.
There is like a solidity to the vibrated words.
Israel Regardie has a great book called the Middle Pillar which goes into great detail on vibration. Now, I will not say that it gets as intense as he describes it, but I can see his point in how the vibration of words can be physically taxing for the practitioner themselves.
Nice. Someone recently mentioned vibration, so I was inclined to think of those two sorts. Thanks for the info, I have that book but apparently missed that chapter.