wilfred2k5

I have so much content between my jukebox, iPhone and satellite, that I'm just getting around to playing with the FM radio.

1. HD radio channels actually sound better than the Sirius/XM ones. I checked the Wikipedia articles and it looks ilke HD radio typically provides 150 kilobits (NOT kilobytes) per second of data. That's 1/10th of what a CD can handle, but the CODEC used more than makes up for it. The result is akin to CD quality with some frequency compression effects (e.g. complex music tends to have bass notes that are on/off instead of different frequencies and treble headroom disappears). However, it's an order of magnitude better than regular FM, something like going from an old analog cell phone to Sprint's fully digital network. No static, no interference, crystal clear.
2. When you tune into a station, it takes a while for it to buffer enough data to begin HD operation. Meanwhile, it's only analog.
3. If you're tuned into an HD1 station, which is generally just a digital version of the analog one, the radio tends to bounce between analog and digital. Sometimes the stations are not perfectly aligned, and you'll end miss a second when it flips. That also makes it VERY easy to tell when you've been dropped to analog. HD stations seem to be more fragile in terms of reception; when the radio keeps bouncing between analog and digital, it's very irritating.
4. If you're tuned into an HD2/HD3.../HD7 station (which are generally completely different content from the HD1/analog portion), all you get is silence until the station can be received again. Satellite cuts off in tunnels and such, but HD radio can drop you if you turn a corner or a tractor-trailer drives by.
5. Audi doesn't handle the HD stations very well. From the steering wheel, you can only select analog channels and you have no indication of whether HD2-7 are available. If you set a preset, it sometimes forgets that you really wanted 103.7 HD3 and just gives you 103.7 HD1. See my next point. This may be because it can't capture the HD3 component at the moment, but it doesn't go there when it does become available. To select it, you MUST use the MMI. The steering wheel controls can't be used to select the proper HD2-7 subchannel.
6. While HD1 is just a digital version of the analog channel, HD2-7 are often wildly different. For example, HD1 is classic rock, HD2 is playing news and HD3 is playing smooth jazz. From what I've read, radio stations often sub-license their other HD channels to their sister TV/radio stations, or other broadcasting companies.
7. Scanning doesn't seem to pay attention to HD subchannels.
8. I really wish there were a way to list what's on all the channels, including subchannels. To find out what's on a subchannel, you have to tune to the analog channel, wait 10-30 seconds for the subchannels to appear on the MMI, then you can see the subchannels for ONLY that analog channel.
9. Not only is it not possible to control HD channel selection from the steering wheel, voice recognition seems oblivious to the concept.

Still, if you still listen to FM radio, it's awesome when the digital feed works, and it's better quality than XM/Sirius.

wilfred2k5

To find a normal terrestrial radio station, try http://radio-locator.com

To find HD stations, try http://hdradio.com . That doesn't seem to be a complete list, but it's a start.

snagitseven

Unfortunately, HD Radio, a terrestrial tower medium (unlike the satellite borne signals of Sirius/XM), operates at a much lower power than FM. As of a couple of years ago, HD Radio was only permitted to broadcast at 1% of FM power. Now, thanks to the constant lobbying by iBiquity, the owner of the technology, it's a whopping 10%, which still provides a relatively weak signal and not all HD stations are even using that yet. Stations also have to determine the chicken/egg investment vs. return potential of their equipment and programming although, with many more vehicles now including HD Radio tuners, the proposition continues to improve, albeit at a snail's pace since the intro in 2002.

Even though the HD digital signal requires less power than analog, it's still wanting. The FCC has had this fear that HD Radio would interfere with FM frequencies and has been loathe to allow the power needed to bring HD reception on a par with FM. Additionally, unlike analog, as the signal gets weaker, it can still be received as you move away from the tower until it's so weak, it's completely lost; digital is either there with good reception or it isn't - there's no gradual decrease in performance with distance or signal obstructions.

Of course, Audi is not alone dealing with these issues - all car brands equipped with an HD Radio enjoy the same sub-par reception performance. Perhaps, in time, the FCC will be persuaded by iBiquity and others to allow further increases in transmission power. If and when that happens, AM and FM will begin their death throes and HD Radio will become the standard. It's a big if though.

Grapeking

Not surprised here, to my ears EVERYTHING sounds better than Sirius/XM....the sound from the Sat radio is just...bad. I'm not an audiophile, but to my ears everything on Sirius/XM sounds very closed-in and tinny, as if everything is being conveyed through a tin can. And it is this way in both our Audi and our Chrysler, which leads me to believe it is the nature of the Sirius/XM codec or transmission itself that is to blame.

The Sat radio service itself is pretty neat, with so many options from which to choose. But the poor sound quality is enough to make me not want to renew when the free service ends in a couple of months.