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Is AM-HD really FM Quality?

Nope. No. Nyet. Nein. HD-AM sounds like an internet audio stream, with a metallic or "chorusing" effect which is fatiguing when listening to the human voice. This is an especially detrimental fault given that most mass-appeal programming on AM these days is news and talk. The "stereo" effect, in the rare instances you can actually get an AM-HD signal to decode in stereo, is disconcerting to me - and I admit I haven't had much experience with hearing AM-HD in stereo (see foregoing reason.) It's reminiscent of those "electronically reprocessed for stereo" mono LP records of the 1960s/1970s where the manufacturers used a delay line and equalization to add a few microseconds to either the left or right channel, giving a sort of "spatial" sound. Like AM-HD, those fake-stereo records were not as enjoyable to listen to as the clean mono source. Fake is as fake does.

Then there is the synthesized high end. There is a kind of novelty appeal here: the unsophisticated listener immediately reacts to hearing "highs" on AM with a temporary kind of "wow." But among the honest critics, the "wow-factor" is short-lived. All highs above 4.5 khz are cobbled within the HD receiver. Like most digital constructs it's an approximation of the original sound, not actual reproduction. And the fuzzy "close-but-no-cigar" audio product is, as noted before, fatiguing. In short order most listeners yearn to turn the dial to listen to something more natural sounding.

AM-HD Radio is Robbie The Robot Radio. It may have initial novelty appeal but - combined with the typical reception problems and the incompatibility with most AM transmitting systems - it's going nowhere in the competitive marketplace. The lack of robustness - nighttime skywave interference and local reception faults like pulse-type, dimmer and power line noise - causes annoying mode-hopping and defaults to analog, often revealing time-sync errors with the main channel. And as noted on the SF board, the adjacent-channel interference is horrific and I predict will ultimately spell the doom of HD-AM, if not HD Radio generally.
 
Definitely not FM quality. I am a regular listener to Radio Disney, and I can tell you that the audio quality is terrible, the high frequencies are muted, and shifted in frequency, phase, and delay, and the majority of time the stations will not decode in stereo. It is a horrible system for music, it reminds me of a less than broadband stream. The sad thing is - the stations have 1/10 to 1/20th the range in stereo that they did when they used C-Quam. VERY poor system, very poorly engineered, and a very poor decision by Radio Disney to use this system, particularly given the limited spending power of their target audience.
 
rbrucecarter5 said:
Definitely not FM quality. I am a regular listener to Radio Disney, and I can tell you that the audio quality is terrible, the high frequencies are muted, and shifted in frequency, phase, and delay, and the majority of time the stations will not decode in stereo. It is a horrible system for music, it reminds me of a less than broadband stream. The sad thing is - the stations have 1/10 to 1/20th the range in stereo that they did when they used C-Quam. VERY poor system, very poorly engineered, and a very poor decision by Radio Disney to use this system, particularly given the limited spending power of their target audience.
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I can't comment on the music, but the HD AMs I listen to in Chicago WBBM & WLS have good sound quality for talk. Far better than their analog signal.
Is it worth the IBOC splatter--NO!
 
Try listening to the KYW 1060 background teletype in AM HD, if you can lock in the signal for long enough.
It seems the top octave of the codec was optimized for music and not sound effects, and HD radio impairs their analog signal and fidelity for the benefit of a very few employees who bother to listen to this novelty.

The analog negative and positive audio modulation peaks must be reduced and audio fidelity cut in half to accommodate all the HD radio digital hiss on the adjacent channels.

This is progress?
 
I've heard WBZ in their talk format and talk is just as fatiguing as music (I've only heard AM IBOC music in commercials), the voices have an eerie unnatural overly bright sound.
 
The analog AM sounds a lot better to me than AM HD but my biggest complaint is the iBLOCK adjacent channel interference.
 
Of COURSE the HD-AM digital may sound better than the analog. That's because they've restricted the bandwidth of the analog signal to 6 kHz, 5 kHz or in some cases - like the Crawford stations - a forehead-smacking 4.5 kHz, in order to provide sufficient bandwidth for the hybrid signal. In addition average and peak modulation is reduced, since anything approaching carrier cutoff (100% negative) will cause the digital to go intermittently out of lock. In some cases, if the antenna load is just right, it can also cause transmitter damage, I'm told.

78 rpm records from the 1940s had this kind of frequency response. The extended-range London FFRR (Full Frequency Range Reproduction) 78 rpm records of the immediate postwar period had a range up to 8 kHz, considered "high fidelity" at the time.

So: HD Radio forces a throwback in audio quality to SIXTY YEARS AGO for the 99.98% of AM listeners still hearing programming in analog. (And of course there are the completely unacceptable adjacent-channel and self-interference issues. It's beyond stupid.)

A much fairer comparison would be HD's digital stream versus full 10 kHz NRSC AM bandwidth - and if we're gonna use a level playing field, the 10 kHz should also be in C-QUAM stereo. I'd bet anybody here a nice steak dinner: the analog would win every time.
 
Sorry, I'm not going back to 1930's sound unless I purposely want to listen to 78's or Wax Cylinder recordings! ;)

So has anyone written an Epitaph for the AM HD Gravestone? Send us your Epitaphs!
 
AM HD Radio 2002-?

Here lies AM HD,
He was Dead On Arrival.
On life support from the beginning,
Almost no one cared about him.
He was belittled.
He was a distant step child to DAB,
Satellite Radio, DRM and C-QUAM.
Most everyone wanted him to go away,
He was a disease to the airwaves.
Good Riddance!

R.I.P. :'(
 
Well put stormy! You only forgot to add that "Wherever he went, a nasty, hissy mess surrounded him and engulfed others"
 
stormy01 said:
Sorry, I'm not going back to 1930's sound unless I purposely want to listen to 78's or Wax Cylinder recordings! ;)

So has anyone written an Epitaph for the AM HD Gravestone? Send us your Epitaphs!
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I'm sorry, but 1930's audio is not an accurate description of AM HD / analog reception of an HD station. I have listened to a 1930's vintage radio, it was a five stage tuned RF model. Frequency response was rich and good for talk and music. Probably not too much on the high end, but it was definitely more than the 4.5 MHz mandated roll-off, music sounded really good with a fair amount of highs. And 1930's AM stations did not self jam with deliberate hiss if you tuned a fraction off frequency. That same receiver was used for 1600 mile reception at night in the 1930's before station glut jammed the dial with useless nighttime modulation.
 
rbrucecarter5 said:
I'm sorry, but 1930's audio is not an accurate description of AM HD / analog reception of an HD station. I have listened to a 1930's vintage radio, it was a five stage tuned RF model. Frequency response was rich and good for talk and music. Probably not too much on the high end, but it was definitely more than the 4.5 MHz mandated roll-off, music sounded really good with a fair amount of highs. And 1930's AM stations did not self jam with deliberate hiss if you tuned a fraction off frequency. That same receiver was used for 1600 mile reception at night in the 1930's before station glut jammed the dial with useless nighttime modulation.
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Oops...my bad...I agree...how about audio from before 1920?

Yes, my 1938 Zenith Model 6-S-254** sounds waaaay better than iBlock!!!
**http://www.tuberadioland.com/zenith6-S-254_main.html
 
I took an old 78, digitized it, and used all the processing power I had to get rid of the surface noise and scratches. The result was incredible sound. Has to do with the wide grooves and high recording speed. Good sound hidden by high noise. Sound familiar.
 
There was an interesting study done after CBS introduced the LP in 1948. It's been forgotten now, but contrary to most perceptions, the LP was not universally embraced. Early LP records did not exhibit particularly good audio quality, for one thing. In fact many of them were panned for having deficient low frequency response and high "tracing" distortion as the pickup reached the grooves closest to the center of the disc. Much of the tracing intermod was due to the prevalence of crystal cartridges in 1948 which had poor compliance.

Most of the enthusiasm over LPs came from the possibility of uninterrupted playing of classical music like symphonies, half of which would now fit on one side of a single record, obviating the changer-cycle interruptions every four minutes or so. The problem was that classical music fans comprised about 15% of the record-buying market, and 80% of industry sales was comprised of pop hits on 10-inch singles that played for 3 minutes max. So initially there was a lot of resistance to buying new equipment, especially among jukebox operators and manufacturers who saw utterly no advantage to long-playing records.

LP records had a groove pitch of 180-220 lines per inch. It was found through experimentation that if a 12-inch 78 was given the same fine "microgroove" pitch, a single side played almost as long as a 12-inch 33 1/3 LP...about 18 minutes versus 25 minutes. Because of the higher linear velocity of the 78 and the fact that the grooves could be carried closer to the label before inner-groove distortion started appearing, they actually sounded superior to LPs.

Proving once again: sometimes "innovation" is, in varying degrees, partly a step backwards technologically. In the end it all comes down to market forces and consumer desires - which in the case of HD Radio, have been disastrously adverse on all fronts.

(Then of course there is the small detail: LP records actually worked. HD doesn't.)

Does "new" invariably indicate "improvement?" Largely that's perceptive. In 1948 and now.
 
Not to my knowledge. However a number of microgroove 10" 78s were produced, including some stereo issues.

www.cool78s.com

I recall getting a promotional copy of a Warner Bros 10-inch stereo 78 featuring specialty-offbeat guy Leon Redbone back when I was PD of 13Q Pittsburgh back in 1977-78. Of course you played these with the 1-mil LP needle, not the usual 3-mil 78rpm needle. As you can see from the site, there were a number of latter-day 78s issued, generally for promotional and/or curiosity appeal.

Everyone's seen Elvis and Fats Domino 78s, but it isn't widely known that there were many 1960s artists who had 78 singles on the market, like The Beatles, Rolling Stones and Herman's Hermits. These records were widely sold in areas of the world where springwound 78rpm players were still prevalent as late as 1970 such as Southeast Asia, India and Latin America.
 
Savage said:
Not to my knowledge. However a number of microgroove 10" 78s were produced, including some stereo issues.

www.cool78s.com

I recall getting a promotional copy of a Warner Bros 10-inch stereo 78 featuring specialty-offbeat guy Leon Redbone back when I was PD of 13Q Pittsburgh back in 1977-78. Of course you played these with the 1-mil LP needle, not the usual 3-mil 78rpm needle. As you can see from the site, there were a number of latter-day 78s issued, generally for promotional and/or curiosity appeal.

Everyone's seen Elvis and Fats Domino 78s, but it isn't widely known that there were many 1960s artists who had 78 singles on the market, like The Beatles, Rolling Stones and Herman's Hermits. These records were widely sold in areas of the world where springwound 78rpm players were still prevalent as late as 1970 such as Southeast Asia, India and Latin America.
Click to expand...

Very interesting info., and thanks for the cool78s.com website!
 
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