Watching the Compression Depression video linked above is making me wonder about something that I noted and forgot about the first time through the course (I am new since Nov 20). Greg demonstrates “mouth compression” and produces decent-sounding notes at various pitches, several above the staff. When I use strictly mouth compression–not adding any air at all, just what can be held in the mouth cavity–I get a noisy squawk. I can make it sound at C4 (middle c), E G and E in the staff; above that just air. Greg’s mouth compression sound seems somewhat like his stab notes in the Ruby exercises. My stab notes sound close to his at Ab, A just above the staff, but am using a burst of “lung and throat air” held back by tongue and then released for the short note, not just mouth air. I am wondering if my understanding of mouth compression is off the mark, or if there is something to be learned to make the “mouth compression” notes sound closer to the “stab” notes. Any thoughts?