Does HD radio sound better than analog? - Page 7 - AVS Forum
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post #181 of 195 Old 12-10-2008, 07:54 PM
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About the Zenith vs. Crosby issue. I discussed this several years ago on FMTunerInfo.org (great site which even features a few of my contributions) taking the anti-Zenith stand well represented here (and done better here). A radio engineer (J. Byrns) strongly disagreed with me. One of the key virtues of the Zenith system is low distortion. Modern tuners can push FM-Stereo distortion way down to nearly zero (I've seen numbers like 0.003%) because there is no theoretical limit. However, IIRC, with Crosby, you do have small, but not negligible, distortion in stereo. On the other hand, as has been explained here, because the L-R AM carrier is higher frequenices, going to stereo gives you higher noise on a weak signal. The noise can be reduced by reducing the stereo separation (blend). So it may be that Crosby isn't exactly perfect either, and it can't be fixed, but the problem that the Zenith system has (noise) can be minimized.

Either way, and even if I wish it had been done better, FM stereo is a fine system, and good enough for human audition. With a strong signal, noise and distortion and artifacts are negligible. Systems based on high compression to get by with low bitrates generally have non-negligible artifacts. The analog system does not degrade quite as nicely at first, but never goes entirely over the cliff as digital does, and for that reason also makes for more fun DX'ing. For a long time I wished HD/IBOC would go away. Now I just hope it doesn't take over.
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post #182 of 195 Old 12-12-2008, 03:43 PM
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charlesp210, do live someplace where multipath doesn't exist? Where I work I have multipath from buildings and hills and even buildings on hills. I haven't found a FM stereo tuner that didn't crank out an unlistenable mess of distortion from most of the stations here.

HD Radio on the other hand works perfectly. No reception problems at all.

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post #183 of 195 Old 12-13-2008, 03:33 AM
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On the issue of sound quality, IMHO, one can successfully trade-in one "evil" for another and enjoy the results. FM Multiplex stereo is NOTORIOUS for "tip-toeing" around the issue of rich spectral energy as you approach 15Khz. It has to duck the "800 pound gorilla" in the room, ie, pilot hetrodyne and consequential subcarrier saturation analog artifacts that plague most tuners. I feel that pychoacousticly, the rich spectral content of the HD radio audio pass-band, provides much needed "top end punch" without having to play with modulation levels or hi-end (frequency-wise) compression techniques to otherwise "mask" the inferior MPX audio pass-band roll-off. Artifacts? yeah maybe with poorly done FM and surely with AM HD audio; it all depends on how the engineers approach it. What crap if any does the source material comprise itself of? Good audio in on a proper FM HD setup (HD-1 and HD-2) can yield decent enough outcome that I'd take any day over analog. Add an HD-3 channel and I'm no longer betting my house on that statement. That's quite tricky to pull off and I'll have to listen hard to examples before I can include that scenario with a "thumbs up".
So long as you've got the signal in the car and the lazy ones don't FORCE HD ONLY/ NO BLEND BACK mode, (now there's a reason to bring back capital punishment!), I'm a happy fish in a clear pond.

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post #184 of 195 Old 12-14-2008, 02:32 PM
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I'll say again, multipath turns analog FM into "crunch". It affects every sound and it's far worse than the worst compression artifact I've heard on HD Radio. The only thing worse with HD Radio is unreliable reception.

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post #185 of 195 Old 12-15-2008, 06:49 AM
 
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Quote:
Originally Posted by dead of night View Post

What has better sound quality, HD music or a regular analog signal?

HD has a quieter sound floor (basically silence), but otherwise I don't think it sounds any better than FM.

I should add that most of my FM stations sound like they are playing CDs with lots of high-frequency components (above 15,000 hertz), so HD would be hardpressed to beat that.
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post #186 of 195 Old 12-15-2008, 10:30 AM
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Quote:
Originally Posted by electrictroy View Post

I should add that most of my FM stations sound like they are playing CDs with lots of high-frequency components (above 15,000 hertz), so HD would be hardpressed to beat that.

Are your FM stations broadcasting in mono so they don't chop off everything above 15 kHz like FM stereo stations do?

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post #187 of 195 Old 12-15-2008, 10:53 AM
 
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Uh... no. Why would the addition of stereo cause the frequency range to drop from 20,000 peak to 15,000 peak?
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post #188 of 195 Old 12-15-2008, 12:19 PM
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Quote:
Originally Posted by electrictroy View Post

Uh... no. Why would the addition of stereo cause the frequency range to drop from 20,000 peak to 15,000 peak?

Because it does. FM stereo suppresses that frequency range.

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The (L+R) Main channel signal is transmitted as baseband audio in the range of 30 Hz to 15 kHz. The (L−R) Sub-channel signal is modulated onto a 38 kHz double-sideband suppressed carrier (DSBSC) signal occupying the baseband range of 23 to 53 kHz.


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post #189 of 195 Old 12-16-2008, 06:31 AM
 
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Alright. Well I don't know anything about that - I just know that my local stations (especially WARM-FM and WROZ) have a strong response on the higher frequencies, such that it sounds like I'm listening to a high-frequency CD with some background hiss.

BTW: Just because wikipedia says the L+R channel is limited to 15,000 does not mean it's true; wiki has lots of errors. If the L-R channel starts at 23,000, then that means the L+R channel could extend upto 20,000 in response.
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post #190 of 195 Old 12-16-2008, 07:59 AM
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Quote:
Originally Posted by electrictroy View Post

Alright. Well I don't know anything about that - I just know that my local stations (especially WARM-FM and WROZ) have a strong response on the higher frequencies, such that it sounds like I'm listening to a high-frequency CD with some background hiss.

BTW: Just because wikipedia says the L+R channel is limited to 15,000 does not mean it's true; wiki has lots of errors. If the L-R channel starts at 23,000, then that means the L+R channel could extend upto 20,000 in response.

In this case Wikipedia is right. You can't go above 15k with stereo FM. It would interfere with the pilot tone and violate FCC rules.

Rock stations usually process the snot out of their high frequencies to overcome the strict modulation limits imposed by the FCC, but what you're hearing is not 15k. Probably not even close.

I don't think anyone is disputing that HD Radio has noticeably superior frequency response to analog FM. The problem, sound-quality-wise, is the artifacts at the most common bitrates.
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post #191 of 195 Old 12-16-2008, 10:31 AM
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Quote:
Originally Posted by electrictroy View Post

BTW: Just because wikipedia says the L+R channel is limited to 15,000 does not mean it's true; wiki has lots of errors. If the L-R channel starts at 23,000, then that means the L+R channel could extend upto 20,000 in response.

And would wipe out the pilot tone at 19 kHz which FM stereo needs to decode the L-R signal.

Mono stations can broadcast up to 20 kHz with no problems. In the old days you would sometimes see the stereo light blink on mono stations because things like crash cymbals would create sound that would hit 19 kHz. Many stereo receivers unfortunately filter out everything above 15 kHz because mono stations are rare and it eliminates some noise.

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post #192 of 195 Old 12-16-2008, 01:41 PM
 
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Good info. Thanks!
Quote:
Originally Posted by narkspud View Post

I don't think anyone is disputing that HD Radio has noticeably superior frequency response to analog FM.

Well I've never heard any difference. FM-HD sounds identical to FM-analog to me, minus the hiss.

AM-HD is supposed to be like FM in quality. So that means a 30-15,000 hertz range? Does it actually achieve that?
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post #193 of 195 Old 12-17-2008, 06:13 AM
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That could also be the way that stations process their signals. If an HD station is lazy and has the same processed signal limited to 15KHZ, your not gonna hear much of a difference (might be a tad cleaner with no hiss). You could record that signal on DVD-Audio, an SACD or even a CD and it would still sound just like FM radio. If a station is daring enough, they pass a more or less un-processed signal to the HD side and that alone can be a HUGE difference and the high frequency extension is noticeable.

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post #194 of 195 Old 12-17-2008, 05:46 PM
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Gentlemen,

After reading many of the posts on here, I decided to take the plunge and try an HD Radio.
I have been in the Comsumer Electronics field for years as a consultant, technician and installer of both home and car audio, as well as an avid audiophile.
The Hd I went with is the add on Sony XT-100HD as I have a Sony head that uses this tuner.
Let me start by saying I read a review of this, either on here or elsewhere, that said 1)this tuner is NOT as good as the one in the head unit (as far as analog reception) and 2)that it "eliminates" the tuner in the head unit (I.E. disables it)
NEITHER of these are true.
Let's address #2 first. The reason someone may have thought the internal tuner is eliminated is that the XT-100HD has NO ANTENNA OUTPUT to loop back thru to the head unit. It only has the antenna input jack. So unless one uses a 'Y' antenna adaptor, there is no way to have the antenna hooked up to both the head unit and the HD tuner module at the same time. But the internal head unit tuner DOES still operate.\\
Now, as to the ANALOG tuner performance of the HD Tuner Module, it is, IMHO as good or better than the head unit's tuner. At least close enough to not wory about (and believe me I listen to distant stations...both AM and FM as I live halfway between Cleveland, Oh and Pittsburgh,PA and work in Pittsburgh. And as we all know, HD will not travel much beyond 40 mi. (Although I almost wrecked my car when I actually received WABC-HD 770 AM out of New York City while just outside of Pittsburgh, East, in Greensburg, PA the other day. naturally went in and out of HD while I drove, but I was stunned! This leads me to believe there is no reason the technology can't eventually allow for further distances that 40 miles or so.
Next, let us discuss the SOUND quality of HD....First AM.....as an AM Talk show fanatic (politics/sports/heath, etc) I listen to AM more than FM.....and I can say without hesitation that AM HD is outstanding!!!!!! For all intents and purposes it IS like FM....at least on talk. Yes there are artifacts that would preclude it from competing with the BEST of FM analog done RIGHT (which so few stations do!) but it is a great improvement over analog and, unlike digital TV, simply goes back to analog when you exceed its terrestrial limits. WONDERFUL except lets get those limits in miles reduced!
Fm DEFINITELY sounds better, IF YOU LISTEN FOR MORE THAN FREQUENCY RESPONSE AND TONE. True audiophiles will understand what I am talking about when i say the imaging, dynamic range and inner detail are all far superior to analog, so long as the station is doing, as MattDP so clearly pointed out, passing relatively unprocessed signal to the HD side. Fortunately for me, many of the stations I can get here in Youngstown, Ohio and Pittsburgh, PA do just that. And it sounds great...WELL worth the investment.
Then, of course, there is the added benefit of no static,noise and multipath PLUS the increased program material (I now have a choice of fine arts/classical, blues, oldies,classic rock, 80's rock, country,r&b and some urban stuff i have no use for on the variety of HD2 available in these 2 cities. Only wish there was more talk AM stations (only 2 in Pitts. and none in Youngstown) that do HD.
Let's hope the technology continues to expand and be used by others while RETAINING analog as well.
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post #195 of 195 Old 12-18-2008, 01:16 PM
 
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They need to boost the HD power from 1% to 10%. The way it is now I couldn't get anything further than 10 miles from center city Baltimore or D.C. (This is in my car; at home it's a little better.) Since my job is about 25 miles from center city, and my hotel about 40 miles, the HD in my car was basically worthless.

If they boosted power to 10% I suspect the range would be almost as good as analog, and they would sell a lot more HD radios.
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