Medford musician Emily O'Brien is offering a series of five online Sunday workshops titled "Practical Music Theory: Nuts and Bolts for Everyday Musicians." O'Brien, who specializes in playing the record, will go over common nuts and bolts topics that will help you learn your music faster and sight read more easily, recognize how your part fits into the context of an ensemble piece, and gain a more detailed understanding of music you hear. Today's opening session is on musical intervals,…