<p>I can answer about playing trumpet. If you are at the level that you are planning to be a Music Performance major, and band is important at that school, that could be just the hook you need. If you are planning to be something other than a music major and are just an average player, band is a good EC to throw on the page but not a hook to get you in. Also, trumpet players are not usually in short supply. Tuba, on the other hand (it's not too late to switch).</p>
<p>How to tell if band is important at that school? If it is a joke band, like Stanford, Rice and too many others nowadays, your potential contribution is worth a cup of warm spit. Where the band is good, popular, constantly featured in alumni events, is hard to get into (audition required), populated with scholarshipped music majors in leadership positions, then you're looking at a real band.</p>