'an erhu' - Extracrricular activity essay for Common App

I have cut about 700 words from the original one, so I wonder whether my language is awkward or I should focus more on a certain point?I would be very appreciate if you can give me any advice on improving my essay!

Although an erhu(Chinese two-string fiddle) player,I was chosen to play zhonghu(bass erhu)in the school Chinese orchestra.
At first I thought it was too easy a task for zhonghu acted a subsidiary role which only has to play staccato notes or long monotone.That idea soon turned out to be wrong. In accord with the main melody, I must catch the very infinitesimal pause to cut in and play in a brief and energetic tone.Playing legato needs to follow the fluctuating mood: making a crescendo as the music climax or a diminuendo when it smooth down.The more I played zhonghu, the more I found its beauty.I realized that zhonghu's low-pitched voice deepened the contrast of rhythms, creating a grand atmosphere for the whole movement.

During the time of being an accompaniment, I learned that even the "simplest" note requires virtuosity and contributes to the harmony of the ensemble, that we shall appreciate every little piece of work, for it has its own value and can make a difference to the whole.

Technical jargon is good in small amounts, but the esotericism of some of these words in the essay is staggering. And, they are very widespread throughout the short statement, which can be difficult for the reader. Application readers are not going to want to look up numerous words in the essay. It's good that you want to show how much you know about your instruments, but you need to be able to do that without complex wording.

In all, the last two sentences are solid; very simple, well written, and get to the point. However, the start is rocky and rather confusing. It sounds like you have an interesting time in this extracurricular, so show it, not tell it.

Thank you so much for the detailed comments!!! I didn't notice the excess of jargon.And about the begining, I'm trying to explain why I play another instrument in the orchestra that is different from the one in my activity forms...well, I guess that part is not that necessary as I thought.

Again, I'm very grateful for your advice!