Question = High Definition Radio Capabilities

Thanks for your comments above. I contacted a local radio station (San Francisco Bay Area) and received the comments below from their Chief Engineer:

“As far as "HD Radio" goes, we are not on with it now. We are scheduled to begin next year, probably in the summer. Our audio quality really won't be any better with it in my personal opinion. It will be heavily compressed and there will only be an improvement in the signal to noise ratio if the digital signal works well in your receiving location. As far as FM goes, the existing analog signal won't be degraded much, though some published studies indicate that the overall analog receivers signal to noise ratio is degraded, the "new digital" channel (or channels) is a very low bit rate of something like 96kb. The codec that the system uses, which is not upgradeable has some issues, though reports I've heard state that it's "quite listenable".

On FM channels that "multicast" (add more channels), it all is the divided up 96kb, so the overall quality degrades as you add more channels. I'm not really sold on all of this at this point in time. We'll see what the market thinks of it, and we will do the finest installation possible, to give the new system the best chance of success, our listeners deserve that”.

Based on comments received so far, it sound like HD radio is not living up to the marketing hype. It may be too early to adopt this technology and I just hope that it gets better over time.

I have one of the two Yamaha HD equiped HD-equipped model RX-4600 AV receivers in the USA for review in The Audiophile Voice in the January 2006 issue. It takes about 55dBf of signal to get it to switch into HD, so basically it might give you quieter reception if you can read by a station's tower lights. Because the requirements that digital buckets can't be overfilled without disasterous distortion, music must be made to conform to the electronics; the heck with adherance to the original waveform, and because fall-back revert to analog, the present analog needs to be further compromised to match the audio qualities of the messed-up digital. Also, the digital uses look-ahead limiting to prevent over-shoot through a delay circuit before release. This means the analog must be delayed by the same acoustic perception -- another distortion circuit is now in the regular audio path. Effectively, it will decrease a station's coverage in half.
AM HD is a BIGGER disaster. The HD reverts to 5kHz analog MONO and is not compatiable with the present C-Quam AM stereo system, which must be scrapped to run HD. You should here WOR going from crisp digital to low-modulation, low high-frequency response analog AM. Can you picture the little guy in your car radio toggling a treble cut switch? Yes folks, this is new and better --YUCK.Also, digital AM at night is a no-go because of the phase differences in the ground and sky wave when they meet, or it can happen close in to a directional-array station because phase differences are used to control patterns and power levels -- like within two miles of WOR. The digital is highly phase-critical.
Don Scott

think further:
audiophile grade channels in xm radio he..he..

Based on the comments above, and my other Radio HD research, I am passing on the Boston Acoustic Recepter Radio HD and putting HD radio on hold. Thanks again for all your comments.