One question that comes up pretty frequently is the topic of being a double major in college, especially the topic of being a double major in music education and performance. I have addressed this question partially in prior articles, for example in my article on choosing a school for advanced study.
Music education is a great program and I do enjoy working with undergraduate music education students. For students considering this program I have one standard thing I tell them; the reason to be a music education major is because you would like to be a music educator. At ASU I expect all horn players to reach a high level as a hornist with the hope that you will contribute to musical life wherever you are and that you will teach high level students. But in terms of entrance level it is somewhat lower. Many students audition for me for the performance degree that play on a level acceptable for music education but not for performance. But realize that if you don’t show that you have a good ear and some potential you will be rejected for music education. It is not enough to love band and want to be a director, you have to individually show that you have made the effort to reach the highest level you can as a player.
Expanding a bit, the essential thing is to be a double major involves completing the degree requirements of two degrees. The catch is that you have to be accepted to both programs and also you have to complete both programs which will very likely take extra time. The more closely related the easier it is in general to complete both programs, but expect that it may take you an extra year.
If you feel being a music educator is among your interests and you also want to strive for a high level as a performer I think generally you are best off just doing the music education degree but with the idea that you will practice hard and achieve as high a level as you can, equal to that of a performance major, and aim to continue with the horn in grad school. It is very possible to do, and certainly among the Master’s and Doctoral students I have had many held music education undergraduate degrees.
That being said, music education is one of the busiest degree programs there is. If it is not something you want to actually do then music education really is not a good program to be in. You would be better to aim at a performance degree if your level is high enough going in or perhaps a BA if a music degree is important to you.
Also please note: if you have the performance degree you can always go back and complete the extra course work for the music ed certification later. You can always teach lessons with a performance degree but you can only teach public school music with proper state certification.
To close, in general I like music education as a program–if you are interested to teach public school–and I don’t in general suggest the double major, but if you feel it important to do both then feel free to go ahead! There are many out there who have done both. Good luck!