Mandolin, by all means! It has a bright sound, but has to be miked. Worked out fine for Bill Monroe. Same for harmonica. My opinion on OTHER INSTRUMENTS for bluegrass. Guitar, goes without saying. 12-string sounds great too, and lots of power. Same for dobro on melody. Bullfiddle is always the preferred bass. Electric bass is okay but mute the strings so they don't sustain so much. Acoustic bass guitars just don't have enough power for the stage. I'd like someone to try the Mexican bass (guitarron) - seems like it might work out soundwise but look funny. Oh well it's all for fun anyway, right? Piano is okay, especially for Jesus tunes. Accordion right hand is a fair sub for violin, but still would rather hear the fiddle. Drums - a small trap set --no cymbals please-- with a foot thumper are okay, if it's done right (like Woody Allen said). I still haven't formed an opinion on pedal steel for blue grass. Is it too far outside the style? == Johnny in Oklahoma City.