TromboneChat

I’ve been playing on Griego 3 Alessi series mouthpieces for years now, which in the UK are considered large as they’re about the same rim size as Bach 3G. Recently I made a darker more centred sound when, on a whim, I tried a bach 4 corp. on a conn 88HCL trombone. However, the trigger register needs more work than before. Has anyone else gone through this and should I stick with the smaller 4 size, especially as the sound seems warmer?

The trigger register should be more responsive with a larger mouthpiece. Downside is if the cup is too large the notes above the bass staff get flat.

It's hard to answer your question directly, though.

A smaller rim on a deeper cup helps the lower register. This is the philosophy of the Helleberg mouthpiece popular with tuba players. A deeper cup with the 4G rim might be just the ticket. You might want to look at a Wick 4BL or 4AL. If you go Doug Elliott, a 102 rim with a G or H cup is a "large" 4G.

If you want the larger 3 size rim but want better high register, a shallow cup might help. A Doug Elliott 104 rim with an E cup might do this.

Maybe, or maybe what you really want is something retaining the 3 rim size, but a bit more efficient/focused than the Alessis.

Saw your profile - you're probably not a million miles from me, and you'd be welcome to try out a Doug Elliott setup in that sort of world... 3ish rim on a Bach Gish cup (I have the E cup Bruce mentions too, but coming from the Alessis that's probably brighter than you're looking for). Send me a PM if you want.

For me, the rim size / cup width is independent from the cup depth and throat/backbore.

There is an ideal cup width for your face and the general total range you need to play. There are ideal cup depths and throat/backbores for specific types of playing, specific registers, etc.

I think of the two as separate things.

Choose the cup/rim diameter to suit your face. Choose the cup depth/shape, and throat/backbore to suit the horn/playing.

Which 3 series are you playing? You may just need a deeper one.