Audioguy, while analog FM stereo CAN sound quite good on the best tuners, most people don't own (and won't own) a Magnum Dynalab! HD at higher bitrates has distortion that's orders of magnitude better than analog FM stereo, wide-open highs that are far brighter and cleaner due to the lack of a pre-emphasis/de-emphasis curve, virtually unlimited stereo separation, and a background that's as much as 25db quieter than the quietest analog FM stereo. Given a well engineered station, like WDAV Davidson NC, the improved clarity of the digital signal (no multicasting on this one!) is startling! It's as if a veil is lifted during climactic orchestral passages. Every instrument in an orchestra can be heard with pinpoint precision just not possible with analog FM stereo. Brushed cymbals and muted trumpets have a glimmering sheen just not heard with analog FM stereo because the abundance of content above 10khz with these instruments is pushed WAY DOWN by the constraints of pre/de-emphasis.
Now I don't know what kind of music you listen to. If you listen to LOUD rock music that's already heavily processed, the "veiling" of analog FM stereo can actually make things sound "smoother", and more pleasant. IMHO rock/pop/country recordings have been WAY TOO BRIGHT for decades, and analog FM stereo can smooth over some of the edge. But if ACCURACY is what you're after, then you've gotta' know this "improved" tonal balance isn't anything like what's on the recording.
But perhaps the most dramatic thing about well engineered, high bitrate HD in comparison to analog FM stereo is when there's no music at all...the pauses between sentences when the announcer speaks, and the background goes DEAD QUIET! Even if you don't hear noise on your analog signal at normal volumes, it's striking when it's suddenly absent. It's like sitting for a few minutes in what you thought was a quiet room, when the air conditioner or furnace suddenly stops. You were even aware that it was running, but it's absence is striking...as is the new silence of the room. Just as the most important think in a video display is it's ability to reproduce black, because everything rises from, and is referenced to that black, the importance of an absolutely "black" (silent) background can't be over-emphasized...particularly with quiet acoustic music (and speech in a quiet studio). The first time I heard this effect (on WDAV), I told my wife "It's so quiet I could hear a mouse pass gass three studios away". I know, you could have gone all day without that image. But it IS true. You CAN hear every nuance in announcer's voices, and in quiet instruments. You can hear pages turning (sheet music and copy0. You can hear the tiniest inhalation and exhalation of breath. You can freaking hear EVERYTHING!
This is one of the things that drives me nuts about anti-HD folks. I am pro HD (on FM), but can readily admit that THERE ARE PROBLEMS, some of them potentially quite large. Why can't anti-HD folks say "you know it does some things very well, but I'm not convinced because......" Saying there is NO important difference in quality makes me thing a)-you've never heard HD on a well engineered station, or b)-you're not a very observant "audio guy". Yes it CAN sound quite mediocre, and many of the advantages I've spoken of go away when stations feed their over-compressed, pre-emphasized signal into the HD encoder! It gets worse when stations get too aggressive with multicasting, and the bitrates tumble. But when it's good, it's VERY, VERY good. And even when it's mediocre, it (HD) provides fully quieted, fully separated stereo sound in rural areas like mine where these qualities are difficult or impossible to come by, even with expensive outdoor antennas. The total absence of noise, multipath distortion, and blending to mono to deal with them, ought to give any serious "audioguy" pause!
