It doesn’t buzz or anything like that. It’s just very very flat, and it gets worse over time. Last time I looked at it, it was playing somewhere around the first F below the C it should be playing (10-blow on a C diatonic - ignore what I said earlier about 10-draw). I expect that it’s just a case of replacing the reed - just that one reed is affected. I bought the chromatic partly out of curiosity, partly to have something of reasonable quality to play while I decide how exactly to deal with the broken one.
I live in France, and there aren’t any Seydel authorised repair shops here (even though I live in one of the larger cities in the country) - the official one for France is in Holland, and his web site got munched by pro-Kurdish hackers. So either I send it back to Germany, or void the warranty by opening it myself to replace the reed or the plate. Either way it’s going to cost a bit as reed replacement isn’t covered under Seydel’s warranty.
The chromatic is good fun, and much easier to get all the notes in the range than on the diatonic. I love the mellow clarinet-like tones in the lower octave. There’s an awesome sound you can get from it if you close the slide about half-way, especially around the C/D on hole 5, where the two notes interact in a particular way.
Yup, I know about slidemeister.org, and I’m signed up there as well.