This video was made around 1995, in Seattle. The person responsible for the project was Jay Bulen, now Dr. Jay Bulen, Professor of Music at Truman State University. This is what I remember about that day:
Jay asked me to arrive (with my trombone) at the University of Washington Medical School at 8 or 9am. He had secured what resembled an examination room that was filled with electronic measuring gear. He had me play on a mouthpiece that had two holes drilled through the cup, one for the camera and one for the strobe light, which flashed in sync with the vibration frequency being produced. This is what creates the wave-like motion of my lips. As you will see, I have a pressure sensor taped to my cheek which is also in my mouth. There was also a sensor on the bell of my trombone and also one in the room, measuring loudness. The white dots on my lips were put on with a wax pencil in order to track the wave motion. All of this produced data for Jay to interpret for his project. One of the camera views is from inside my mouth, looking out through my lips. That was a real challenge for me, to produce a sound with a camera in my mouth.
When we started the tests, there was an almost immediate knock at the door, a clearly irritated knock. It seems that they had not exactly expected noises such as these that morning and a discussion ensued. This video begins after we were given the "all clear."
There are a couple of embouchure concepts that this video highlights. It shows that both lips are actually in motion during the buzz and it also shows a very distinct difference in aperture size from low B-flat to high B-flat. This is very valuable information to those who struggle with their upper register. So often, as a teacher, I encounter players who attempt keep their aperture as open as possible at all times…to get a "big sound." As you will see, I allow my aperture to close down naturally as I ascend into the upper register. It helps produce clarity and reduces fatigue.
Portions of this video were used for David Finlayson's "Waltz of the Two Lips" which has over 190,000 views on YouTube. David is the most creative guy I know.