I’ve been on an a journey back to playing trombone after nearly 25 years off. At 54, as expected, things felt awkward at first but after a few weeks of playing daily, I was pleased with the comeback. However, I am struggling with repeated articulations in the middle and upper registers. The first note is usually clean, but followed by splats and fuzzy starts to the rest. This is especially the case on repeated notes. For example, the classic Remington repeated eighth notes followed by a half/whole note that used to feel easy now feels impossible. This is not the case from low E
(i7th pos.) below the staff up to D 
in the staff. This low range feels good and sounds the way I expect, yet I can’t do the same in the middle and upper registers.My first teachers
urged “Tah” and “Toh” articulations for nearly all notes. Even on a legato passage, I articulated with a “t” and connected the notes with airstream and clean/quick slide technique. And this seemed to work fine when I was 25.As I’ve explored this challenge, I’ve tried some things:
-See where your tongue touches on low notes, do the same for high, put it somewhere in between for the middle register.
-Use nah-nah-nah-nah-naaaaaaaah and ne/ni instead of tah/toh… for repeated tonguing.
-Avoid focusing on it and spend time on legato etudes.
-Experiment with various tongue positions/movements to find the clean start to notes.
Additionally, I’ve noticed some other commonalities:
-I can gliss through any musical passage with good tone and a clear sound in any register.
-Even with legato playing my sound immediately turns fuzzy and strained when I use my tongue to articulate on notes middle Bb and higher.
-I get some better results when I focus on bumping each note start with a bit more air which cleans the front of notes but adds a bump up in the volume on each pulse of air.
-For legato playing I can feel and hear good note starts (initial and repeated) when I consciously tongue “nah” toward the roof of my mouth, near the center.
I sought help from some experts and am currently using their collective advice to mix in the following strategies one at a time or combined in my practice sessions.
1. Confirm a good focused embouchure (thank you, Doug!)
2. Avoid using your tongue at all for note starts or use “nah/dah” or mix it up like “tah-dah-dah” or “tah-nah-nah”
3. Spend time starting all articulations with only air and buzz.
4. Try to imitate the good articulations from the low register by gradually moving into the middle via a scale or melody.
5. Spend some time on my smaller horn- alternating between .547 and .500 bores. Same MP rim (see equipment above)
Finally, I should note that this repeated tonguing issue seemed only subtle and quite fixable when I started playing every day. Everything needed work. But once other aspects of my playing got better, this repeated tonguing issue seemed to get worse. I even played on a couple of concerts with no concern or problems.
As I eased back into things, I did an equipment check and landed with the following:
Edwards T-350 (1993) w #1 lead pipe, yellow brass bass crook slide (lightweight!)
Olds Studio (1953)
Mouthpieces - DE XT F+/G8/MN103, DE XT C+/D2.5/MN103
Assuming I haven’t developed any physical dysfunction, I’m under the impression my improvement will continue. But, I would really love to hear advice from this group about how I introduce clear articulations in the middle and upper registers. I’m having trouble seeing a future moment in which my tongue suddenly starts doing what it should.
We change a little bit. We loose something but we also gain something.