malletjazz.com FAQ pages
Should I use pickups or microphones to amplify my vibraphone?
If youre not sure, use microphones. The reasons to use pickups are 1) you want to use effects processing (chorus, reverb, etc.) as an integral part of your basic sound, treating your vibes plus pickups as an electronic musical instrument distinct from the acoustic vibraphone sound, or 2) youre playing in really high-volume situations where feedback and leakage are serious problems when you try micing your vibes. Pickups are great - I use em all the time - but theyre not going to give you the same sound as micing will. (Theyre more accurate than some folks want to admit when it comes to giving you a natural vibes sound, but they arent 100% there.)
My comments go double if youre recording - unless you want a processed vibe sound, use microphones. Tracking the vibes using pickups and mixing it without effects is probably not going to give you the sound you want. As they say, tho, YMMV!