Why are my single coil pups noisy at certain angles to my amp and dead quiet at other angles? Can that be "cured" by cavity shielding? Thanks for any thoughts. Stay safely low.
They're noisy because they're basically big antennas. Noise signals are directional in nature and an antenna's orientation matters - think back to the days of screwing with the rabbit ears on your TV to get a better picture. Shielding can help but it's very hard to get single coil pickups to be dead silent in all environments. If you really care about noise on all possible use cases then humbuckers are going to be in your future.
Single coil noise is directional. Shielding is for RF interference, not 60hz hum (single coil noise). I would always suggest a good shielding job but you will need to either balance your single coils (use an even number of single coil pickups at once) or get humbuckers if you want a silent bass.