Seems in the past people talked about telephone quality versus AM radio quality versus FM radio quality versus CD quality.

And to further confuse, there's PCM versus other encodings and besides the number of bits (4, 8, 12, 16, 24) there's the sampling rate in Hz. According to my PC's sound recorder (using PCM):

8 bits at 8 kHz being is 7 kb/sec,
8 kHz at 16 bits is 15 kb/sec,
8 bits at 12 kHz is 11 kb/sec,
16 bits at 16 kHz in 31 kb/sec,
16 bits at 22 kHz is 43 kb/sec.