<p>I think you need to think about why you are in band, and what you want out of it, and what you would lose. Answering those questions will help you decide which direction to go.</p>
<p>If you are in band to fill up a spot or because your friends are there, have consistently played last chair, never practice, and are taking it because your only other option was metal shop and this sounded better - then go ahead and drop band and take piano, and figure out something else to do with your class period.</p>
<p>Nonvoluntarily could mean different things. Varely rarely do you not have any sort of choice. As in Thumper’s example, the student still had a choice: switch or quit. (Sad, but still a choice.) But maybe you perceived it as not having a choice, simply because you respected the teacher’s authority, or had a desire to please. Maybe the band director had a good reason - as soccerguy mentions, some people are physically better suited for different types of instruments. If the band director needed a euphonium, and you showed little aptitude or interest on the trumpet, didn’t practice, and were actually harming the band with your attempts, then it might have seemed like a good solution to the band director - a way to help you out while also helping the band. </p>
<p>On the other hand, if you were doing well on trumpet, enjoyed it, practiced and were making progress, and none of those things are happening on the euponium, then you have a very strong argument for switching back.</p>
<p>My S is a french hornist who was under strong pressure to play mellophone in marching band. His horn teacher discouraged him due to embouchure issues, and he was caught in the middle for awhile. He didn’t want to play it, but he hates to displease anyone. He did it for a year, then called it quits. Because he was a valuable band member on his instrument, and had solid reasons for his decision, the band directors had to give in. (FYI - same S is now a professional-level musician.)</p>
<p>Piano can be a separate decision. You can take lessons if you want, regardless of which brass instrument you take. Consider whether or not you have the time to practice two instruments. If you decide to pursue piano, make a decision up front to continue for a year and commit to practicing. I don’t know what year of HS you are (or even how Australian HS works, for that matter) but you don’t really need your college aps to show you starting and quitting lots of things. (Full disclosure: I am a piano teacher.)</p>