Question = High Definition Radio Capabilities

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.

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

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

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.

by default it can't be.
dynamic range as well as freequency bandwidth is very limited for the HD standards.

Nice to see that you still get quality radio. Pittsburgh doesn't anymore.
Yes, I use xm on my computer. However, I would never bother running XM through my single ended triode gear. I would rather spin an album.
Happy Listening.

Elevick-

I am sorry you have such horrible experiences with broadcast radio and I cannot offer contrary evidence, with only a rare exception or two. I have no experience with ClearChannel, I am happy to say.

However, my point was that the so-called HD-Radio is not an improvement and will likely lead to further corruption as more and more channels are packed into the fixed bandwidth.

Lately, I've been fooling with XM reception which is a good example of such. The broadcast quality is no better than it has to be to accommodate all the channels. By comparison, my reception from WQXR-FM in NYC is superior, as is what I get from digital DMX cable-radio in CT. I do not expect this to continue and I will have to rely even more on my music collection (and the internet).

Kal

You have to do some serious research. Most radio stations are sending out such garbage (compressed or worse)that it probably won't be worth it. Clear channel is a huge culpret-they put everything on a hard drive, compressed with heavy duty, low sound quality sources that will prevent the sound ever from coming even close to a redbook cd through a simple $150 cd player.
I have seen what is local in pittsburgh. WQED, for example, uses single bit sony 300 disc changers when they aren't using their massive hard drives with compressed music-SAD :(
I got rid of my MD101 when I couldn't find any more analogue stations.

HD is a poor term for it. Does anyone really call it High Definition?

It is also known as IBOC (In Band On Channel) radio. It is a compressed digital transmission which allows the channel lessor to pack more channels/functions in his alloted bandwidth. Quality can be good but there's no guarantee.

Kal