AKart and Rogerio,
What works for me may not work for you and your instrument, but I am currently playing a Naumann E5B (available only through Barry at the Baroque Trumpet Shop I believe). I have tried many and played a few different pieces in the past. In addition to the E5B I will also play a couple different Egger mouthpieces I have, depending on the situation. Some mouthpieces will work with one crook but not another. And a mouthpiece that works on my Tomes trumpet may not work that well on my Egger trumpet. The rim on the E5B doesn't suit me the best, but I use it anyway because it gives me the best combination of tone quality, intonation, and accuracy.
In our baroque trumpet ensemble you will see a variety of other mouthpieces: Egger (sizes 6, 7.5, and 9) , Naumann (Eklund model), and Webb, if I remember correctly. A couple of the other players will even use two mouthpieces - a bigger one when playing the low parts. I don't think that any of us feel we've found our ideal mouthpiece, but we've each found something that works for us.
I find the biggest barrier to selecting a baroque trumpet mouthpieces that works well is finding one with decent intonation. Many of them are quite flat in the low register, then go sharp up top. Dealing with can introduce tension, which is a real killer when playing baroque trumpet. Yes, you'll need to bend some notes to get them in tune, but you'll want the partials that don't require bending to line up as close as possible. If you can find a piece that plays fairly well in tune, stick with it for a while. You're more likely to find your sound using it than a mouthpiece that makes you work harder. It will also make lipping/bending easier when it's required.
AKart, like Rogerio, I am anxious to hear about baroque trumpet in Russia. It's great to hear that you are a baroque trumpet pioneer there!
