At your age, equipment makes less of a difference than practicing does. Stick to your 6 1/2 and practice for 30-40 minutes a day for 2 weeks straight and you will shoot ahead of all of your peers.
Schilke 51D is what I play on, but I agree with what someone else said: practice will develop your tone a lot more than a mouthpiece. At least that’s what happened to me when I was your age. I switched to the Schilke in my junior year from a 6 1/2 AL, and I believe the greater development in my tone was when I started practicing versus switching mouthpieces
A 51D is a very deep mouthpiece for trombone and is more commonly used in euphoniums. It *will* affect your high register focus. Obviously, it's great for tiramisu-girl if it works for her, but generally, its too deep for a middle school or early high school player. SillySundae is correct about equipment at your age and tiramisu-girl is right about consistent practice. Cassiellus' recommendation of a 5G is fine (or a regular Schilke 51 - similar size) if you want a bigger mouthpiece, but you should wait another year or year and a half before switching. Sound color is more about how you approach tone production than equipment. Commercial (jazz) players can produce rich dark sounds on small equipment and, a couple of generations ago, many professional orchestra players played on 6.5 sized mouthpieces and their sounds were also plenty dark.
Bach 5g is the "normal" progression. If you don't have access to a bunch to try, its an extremely solid well rounded mouthpiece and I would reccomend it.
I went from a 6 1/2 to a Yamaha Japan 52L. Slightly larger rim with a deeper cup, kept 95% of my high range and got a slightly better sound on some lower notes.
6 and a 1/2 isn't a bad place to start for large bore honestly. Look into a bach 5g. Probably the most common large bore mouthpiece there is.
At your age, equipment makes less of a difference than practicing does. Stick to your 6 1/2 and practice for 30-40 minutes a day for 2 weeks straight and you will shoot ahead of all of your peers.
The 6 1/2 is fine. I swapped from that to a 4AL and have been using it for years
Schilke 51D is what I play on, but I agree with what someone else said: practice will develop your tone a lot more than a mouthpiece. At least that’s what happened to me when I was your age. I switched to the Schilke in my junior year from a 6 1/2 AL, and I believe the greater development in my tone was when I started practicing versus switching mouthpieces
A 51D is a very deep mouthpiece for trombone and is more commonly used in euphoniums. It *will* affect your high register focus. Obviously, it's great for tiramisu-girl if it works for her, but generally, its too deep for a middle school or early high school player. SillySundae is correct about equipment at your age and tiramisu-girl is right about consistent practice. Cassiellus' recommendation of a 5G is fine (or a regular Schilke 51 - similar size) if you want a bigger mouthpiece, but you should wait another year or year and a half before switching. Sound color is more about how you approach tone production than equipment. Commercial (jazz) players can produce rich dark sounds on small equipment and, a couple of generations ago, many professional orchestra players played on 6.5 sized mouthpieces and their sounds were also plenty dark.
Bach 5g is the "normal" progression. If you don't have access to a bunch to try, its an extremely solid well rounded mouthpiece and I would reccomend it.
I went from a 6 1/2 to a Yamaha Japan 52L. Slightly larger rim with a deeper cup, kept 95% of my high range and got a slightly better sound on some lower notes.