Acoustic guitar, drums are a good signal - lower quality just sounds hollow / spacey. The most obvious a/b was the Gamma Ray sample, imo (with mid-range Beyer headphones, wired). It's easiest to tell with recordings you know well, for me Steely Dan is a good reference. I rip to FLAC for archiving even though 320 or 250+ VBR is probably 'close enough' unless I'm scrutinizing.

> I rip to FLAC for archiving even though 320 or 250+ VBR is probably 'close enough' unless I'm scrutinizing.

MP3 is fundamentally flawed and has audible artifacts no matter what the bitrate is. If you use a newer codec (AAC or Opus) you'll probably not notice anything.