My first big studio job was as a runner at The Power Station. We had a session with Jason Corsaro who could tell a mean story, but that's a digression. Charitably, I'll just say that he'd spent a LOT of time in the studio and maybe didnt hear so well anymore... his secret sauce for kick and bass was watching the woofer surrounds crinkle on the NS-10s. He knew just what to look for to get his sound "visually". We also went though a lot of woofers that week.