“On standard-speed LPs, however, some grooves, especially those representing very quiet sounds, are so tiny and so tightly curved that no cartridge can track them perfectly. As a result fine details — the full shimmer of a cymbal, the vibrating wood of a bass, the sense of real people playing in a real space — get a little bit smeared.
But the grooves on a 45-r.p.m. LP are spread out more widely. Their undulations are much less sharp, so they’re easier to navigate. “The cartridge ferrets out a lot more low-level detail within the groove’s walls,” Mr. Hobson said. “It connects you a little more closely to the live music. We’re trying to do time traveling here.””