OK. So I've only been taking fiddle lessons for a couple months and I'm still a bona-fide noob; humor me please. This question has to do with the basic timing of bluegrass fiddle. My teacher has been teaching me a lot of tune back-up stuff to give me a solid foundation for other learning. I just Nashville shuffle in beat with a guitar (long stroke with his "boom", and two shorts with his "chick"). But I'm looking at sheet music and how to apply shuffles to them and I'm a tad confused. The limited resources I can find say the "long" is a quarter note and the "shorts" are two eighths that land on the back beat which makes sense to me. What confuses me is with the last lesson my teacher was playing his guitar and said each "boom" (or my long) was an eighth, which would make my shorts sixteenth notes? This doesn't make sense to me because I thought a "beat" was a quarter note and if that's true, his whole "boom-chick" would be a quarter note with it having an on-beat and an off-beat in a single beat.....? This could've probably been worded way simpler so I'll restate the question as simply as I can...... is the long-short-short rhythm of a Nashville shuffle one quarter note and two eighths, or one eighth and two sixteenths or...???
It sounds to me like simple confusion over the time signature. In 4/4 time, each guitar "boom" is indeed a quarter note, followed by a "chick" that's another quarter note. Each measure will contain two boom-chicks. If you're playing a basic shuffle, you'd play a long stroke on the quarter and two short strokes as eighth notes.
In 2/4 time, as a lot of fiddle tunes are written, the "booms" and "chicks" are eighth notes. There are still two sets of them in a measure (4 eighth notes in the measure giving you 2 quarter notes of total duration). Your shuffle bow strokes would be an eighth note followed by two sixteenth notes, and again there are two of these per measure.
It's almost literally six of one, half-dozen of the other. It's just a semantics thing.
In a bluegrass jam I would go easy on using a shuffle to keep rhythm. Maybe if you're trying to emphasize an old-timey sound. Otherwise it can be "the fiddle is always playing" brand of distracting. Check out how bluegrass players use rhythmic fills to avoid clashing with the singer. Both in playing rhythm and in avoiding playing in the the singer's vocal range