I've been having this issue the semester and a half or so, in which I essentially woke up one day and my low register was gone. Specifically, notes that are below the staff but above the pedals I could no longer play. I've been fighting with this for this entire time and have not been able to find any good remedies or explanations, and that register is still almost untouchable. As a bass trombonist, you can understand why this has given me a lot of trouble.
It feels as if my embouchure just doesn't know what to do down there anymore, like I'm blindfolded throwing a dart if I attempt to play a note in that register. If I'm able to work down there (such as down a scale), I can generally produce the pitch, but the sound is very anemic and often times I can't hold it for very long.
There are a lot of things I've discussed with multiple teachers to attempt to ready this, but nothing has worked. Here are a few of the issues I've talked about:
- Aperture too open.
Aperture too loose.
Tongue blocking the air.
Not enough air.
Mentality/psyching out.
I used to have a very powerful low register, and took pride in it but it's very frustrating having just lost it over night. If you have any clues or have also experienced something similar, please give me a shout!