Dear Professor (Sobrenome),
My name is ... and I am a Brazilian (violinista, violista/etc) currently studying in (cidade.) I would very much like to apply to your class for Bachelor’s/Master’s at university/conservatoire. Would you have time for a brief tryout lesson in (month), before the audition?
Below are links to recordings of my playing and I've attached a letter of recommendation from Full name of Musician (se você tem, eventualmente mande também uma carta de recomendação em anexo)
I so appreciate your time and look forward to hearing from you!