I just ripped Coltrane's Blue World, Apple lossless, and the bit rate is lower than I'm used to -- ranges from 411kbps to 464kbps. When I look at other dBpoweramp CD rips, they tend to be around 1000kbps -- though now that I'm looking, I see some albums have higher ranges (Coltrane e.g. The Complete 1961 Village Vanguard Recordings, mostly above 1000kbps) and others lower (Both Directions at Once: The Lost Album, between 500-600kbps).

I'm sure this variation is explained somewhere but my searches have been unsuccessful -- help please?