I'm a fresh new band teacher and I'm having an issue with one of my French horns. I have two doubles with trigger and one without. The French horn without the trigger wasn't matching the pitches as the other two and I played it with a tuner and found out it was playing a half step lower. I played the lowest open partial and it was Eb. Aren't French horns only F and Bb concert? I dropped a snake a little ways in the bell and there seemed to be no blockage. If I blow air through without the mouthpiece it seems to come out ok. All the notes play ok and all the tuning slides are in. What could the problem be? Thanks in advance.

French horns are common in F, Eb and Bb. In my limited experience in small middle/high schools, though, I've only ever seen F/Bb doubles and F singles. Are there any identifying markings on the horn that you could give? Brand marking, serial number, etc. Perhaps someone on here knows where to find that information exactly.

In elementary school, I did have a Conn single F horn with an Eb extension slide you could swap out. If it's a situation like that, check to see if one of the tuning slides is extra long (probably wrapped around itself to fit the extra length). There may be another tuning slide (hopefully still with the horn) you could change out to put the horn in F.

Case in point: https://www.8notes.com/f/51_347340.asp