WBZ 1030 sounded great on a good quality AM mono radio with good AM bandwidth when it was broadcasting in AM Stereo.
AM stations that broadcast in HD have to drastically cut their analog high-end audio bandwidth to prevent any artifacts from getting into their sidebands which could interfere with the HD, as WBZ did when they went HD.
However, as the NRSC committe that analyzed HD and analog bandwidth concluded about 10 years ago, the average consumer radio has rolled off over 20 db at 5 kHz, so it does not make much difference.