The word Schalmei can mean some different things:
https://de.wikipedia.org/wiki/Schalmei_(Begriffskl%C3%A4rung)
The kind of brass instrument you refer to is also called Martinstrompete, see https://de.wikipedia.org/wiki/Martinstrompete and https://de.wikipedia.org/wiki/Folgetonhorn#Martin-Horn/Martinshorn (In German, “Martinshorn” is also the word for the sound-making thing in fire engines, and yes that is technically related.)
The word Schalmei can mean some different things:
https://de.wikipedia.org/wiki/Schalmei_(Begriffskl%C3%A4rung)
The kind of brass instrument you refer to is also called Martinstrompete, see https://de.wikipedia.org/wiki/Martinstrompete and https://de.wikipedia.org/wiki/Folgetonhorn#Martin-Horn/Martinshorn (In German, “Martinshorn” is also the word for the sound-making thing in fire engines, and yes that is technically related.)