HD Radio is a viable option to improving FM performance

[SignalSeeker]

I have been using HD radio for two months now. I purchased the Sangean HDT-1 component tuner. I am really dismayed at the number of negative posts, condeming HD radio. Especially from those who have not tried it or heard it. I waited for the Sangean because I wanted it in the purest form available. I did not want a table radio. I was not disappointed by Sangean's tuner. When I connected it to my rooftop antenna, I immediately hit the seek function. I was surprised when the tuner stopped at some of the Philadelphia stations, 60 miles east of me. My traditional hi-end tuners had no problem receiving these stations, but the seek control did not pick them all up. I was pleasantly surprised when the HD indicator lit up and then displayed the fact that I could listen to 1-2 additional formats on the the same station. They were crystal clear! I receive things I could not get with traditional analog radio.

The digital side of the HD tuner is great. Now take the fact that RDS never really got off the ground here in the US. I am really happy that all of the digital channels have text built into the broadcast. We have been behind the Europeans for years in this regard. What is wrong with improvements to FM technology. The negative posts about an inferior system, just aren't true. That is a far as listening tests have shown. I have not seen any evidence of cross channel interference from the HD signal. They broadcast it at limited power now, but as I understand it, will be increasing the power as testing procedes.

The first affordable tuner to hit the market was Sangean. The forums tore it apart, literally. The biggest criticisms were about the analog side of the tuner, its blending of the stereo signal to avoid noise, and high THD. The Sangean also does not have a way of manually switching back to analog after the HD signal is detected. I don't know why anyone would want to, when they can receive a discrete digital signal. I have read no negative points about the tuners sound on the digital (HD) or hybrid side. All agreed that the Sangean had better selectivity than any of their audiophile FM tuners.

I have heard that different broadcasters have mishandled the HD signal. Usually boosting the high frequency end, as they would have done with their analog signal. But many listeners say that station engineers that are reacting to feedback from us have a HD signal that is superior to the analog one. That's the key to this, give the stations some guidance. Let them know about your reception. I have written a couple of the stations in the Philadelphia area, they were overjoyed to have a field report from the Lancaster Pa. area. They were very curious about their signal, but especially about the HD signal.

I watch posts about artifacts on HD, truthfully, I have never heard any. I see posts about the limited power of the HD signal. You have to understand the nature of digital signals. They don't require as much power. I get the HD signal as far out as 80 miles when I tune to the Baltimore and Washington DC stations. Don't mean-mouth a new technology until you hear it.

I am very pleased with the Sangean tuner. They promise to improve any of their shortfalls in their next tuner. I will give them my business again. They have proved that they understand the plight of the HD developers, and that is to put the technology into to reach of everyone.

 

[Mike Walker]

SIGH! Show me somebody who "hates HD", or "sees no justification for HD", or "deplores this defective technology", and I'll show you somebody who hasn't tried it in his/her home! For those of us who listen to "serious music" (classical, acoustic jazz, and other forms of acoustic music) the complete absence of noise, full frequency response even at the highest levels of modulation, and total elimination of multipath distortion are a revelation.

 

[PhilJSmith67]

Now take the fact that RDS never really got off the ground here in the US.

More stations than ever are running RDS today. Most stations adding HD Radio either already had RDS, or have added it as part of their "digital suite." RDS is even showing up (again) in after-market receivers, such as many of the new Alpines. RDS is prevalent in suburban and rural areas where HD Radio is nowhere to be found.

Granted, the initial push for RDS didn't take off in the U.S. in the mid-1990s, but with the popularity of receivers with artist/title display, RDS has made a major comeback.

As for reception, the HD signals don't have the coverage of the analog. But, it's also not as bad as some of the detractors make it seem.

 

[tomservo]

Of course all this only applies to FM, not AM. We've pretty much agreed that the digital scheme on AM has some serious issues which need to be addressed.

I'd like to offer more than a passing opinion on HD, but as of yet no ones does it here. I'm not counting the weak AM's from Memphis, 100 miles away. I'm confident that HD will never be "on the air" here unless the state's public radio network switches it on. The costs of installation is gonna have to go waaay down before everyone is converted & covered. The small-timers here can't even run the commercials at the right time, much less handle two more HD-only feeds.

It would be nice, if the forum, wasn't littered with, certain people, who shall go nameless, but one of whom, uses too many commas, because these people, have nothing but negative things to, say. We get the point -- you hate HD radio. Fine. Don't listen to it. We all agree that AM HD is a boondoggle and should work together to get this issue resolved. It doesn't take constant posting of Google Trends links.

Besides the people who listen to "serious music", I can see this format also benefitting people like me who live in the middle of nowhere and only have 3 local FM's... But as I said before these guys are small potatoes, meaning little money. So in this respect, the HD option isn't viable. It's a shame. I'd love to see incentives for smaller FM stations to make the switch, instead of high costs and ongoing license fees.

There's a lot of hurdles yet, and the people who've tried HD seem to acknowledge that.

(FWIW, I've always been a fan of RDS as a nice supplemental data service. It's pretty robust as designed, but it never took off here as it should have. Radios from the beginning should have implemented both the program service (ID) and radio text fields, though. That woulda saved us from this stupid Dynamic PS that results in garbled displays when in a moving car...)

 

[tomservo]

OK, I went to clean up that last post and re-think and re-iterate my feelings on the subject and now it gives me an error, saying the time to edit the post has expired. WTF?? This stinks. The one time I hit 'Post' instead of 'Preview', grr..

A few more points, since I can't change what I wrote, like this is all set in stone in a cave...

I've come around. I started lurking here as an anti-HD-for-so-many-reasons fellow. The commentary of some of the more level headed folks has swayed me to be more open minded. I'm no longer vehemetly anti-HD on FM. It's a "if you don't like it don't buy into it" scheme. Easy enough. I'm still anti-HD on AM because it's going to adversely affect nighttime reception and it absolutely kills what little fidelity analog AM has left.

I'm no longer anti-HD, but I still feel it's just easier to listen to satellite radio, to be honest. The sound quality isn't great and there are coverage gaps here and there, but overall the music I want follows me wherever I go. Of course the catch is for not having commercials on almost all the music channels there's that pesky monthly fee... Which poor Delta farmers may have trouble justifying... But the content is totally worth it for those of us who can.

Mike, be careful about applying terms like "for serious music listeners" and whatnot -- it seems like just about anything aimed at the high-end market is a failure with mass consumers. If too many people get the idea that HD is just for haughty-taughty classical lovers, they won't see the justification for it. (I know, I know... No one is pushing that publicly, but after seeing great hi-end stuff like DAT and S-VHS die and the tumble in picture quality that has begot the sat-TV providers over the years, I don't wanna take any chances!)

 

[Mike Walker]

I agree with you Zach that being classified as an "audiophile" technology could be the kiss of death for HD. But I see three markets for HD. 1)-people who want more variety...the "general" listener. To him/her multicasting is the ticket. 2)-people in areas where multipath is a problem. HD flat-out cures it. And finally 3)-people like me who DO listen to music on the radio "seriously", and find "full" bitrate HD (sand-multicasting) to offer compelling advantages over analog (full 96db dynamic range, distortion NO analog system can manage, and a crispness and clarity that are startling, due not to much to extended frequency response on top as to the lack of 75us pre-emphasis).

Actually I'm in categories two AND three. Many of us are in more than one category. But I see myself as PRIMARILY being in number 3. Admittedly those of us in the third group are the minority of HD listeners...people like me who hear HD-2 stations and think "that's swell", while hitting the preset to go back to classical or some other form of acoustic music. But as long as my local public stations are HD, and continue to offer such outstanding sound quality, and as long as there are SOME HD radios/tuners available, why should I care. (To answer my own question, I SHOULD care because broader acceptance of the technology will mean greater availability of programming AND radios/tuners).

 

[stevenNOLA]

I fit into 1,2, & 3. I'm in a large metro and multipath is horrible, especially in the shadow of the downtown buildings from 2000' tower farm. Fortunately, there are about 4 HD2s that I listen to on a regular basis, all rock-oriented (Wide-playlist alternative on KTBZ-HD2, All 90s KHPT-HD2, AAA KKRW-HD2, and 60-70s hits KLDE-HD2). I other cities, I would have no benefit from HD radio because I do not like "Future Country", "Future Hits" or "Comedy". Sirius Raw Dog and XM's comparable channel are unedited and are the way comedy should be IMHO (a whole other debate).

 

[Tom Wells]

Each market's HD advantages will weigh against same market's disadvantges, and even unknown disadvantages regionally due to building construction, topography, ground conductivity, and other special features like the lovely city "sproutlets" sprinked around greater Dallas, providing lots of multipath for everyone in the Metroplex!

I live far enough from downtown Chicago to not suffer overload, but not far enough to ever suffer more than airplane flutter sometimes.
Mostly they are noisless and perfect in analog, so at 7 miles... not worth it for me compared to FM analog.

I gain nothing from HD but possible extra channels. I doubt their variety will equal the local offerings from college stations.


The wise major market FM with HD would sign up the coolest local college fm for an HD-2.
Yes, they're still gonna sound like college kids, but you'll hear what the P.D. and music director would never never let happen:
All-Day-Train-Crashes. The difficult listening hour, etc.

I'll be impressed an even likely BUY if somone bold programmer says" %#@! formats, we're playing every&$%!$@# thing. Hang On."

But that won't happen, so I'm mostly happy it doesn't seem to hurt regular FM except for it does make the tuning a bit mushy.

Some places will have good clear line-of-sight with little multi-path, others with more-or-less of either, with predictable HD decoding success rates.

Having synchronized manually a teletype using amateur radio RTTY signals, which are 45.45 baud digital, you get a feeling for
how much signal "needs to be there" before the triggering circuit will recognize the frequency shift.
And how it sounds when it's not quite "solid" enough.

Many places may find an improvement on FM.

I think the best FM 96k stream Mike Walker posted was good, but sounded like it had the 75 us pre-emphasis in the HD.
The telling point was violins that have more "zing" than a live violin.

Maybe it's insufficient no. of bits of resolution? Like not enough gray scale resolution.....

Even so, it will be an improvement over bad FM. Unless HD-2 and 3 come on line then all get garbly.

 

[Mike Walker]

Without access to the individual cd Tom, I'd only be guessing, but I think "it" (the extra bit of "zing") is that little bit you would GAIN from HD...high frequencies that can be as loud as midrange or low frequencies, due to the LACK of pre-emphasis!

As you no doubt know, 75us pre-emphasis is RADICAL at certain frequencies. The boost becomes ENORMOUS as frequency increases. Which is why the announcer's voice would be horribly "zingy" on "s" and "t" consonants if 75us really were being applied to the HD signal path. Think about that, relisten to the SPOKEN part of the broadcast, and you'll see what I mean. There is no pre-emphasis present.

We have all gotten used to the rounded, less than pristine sound of rolled-off highs on analog FM. It sounds "natural" to us. I thought HD sounded very bright at first...until I listened some more. Recordings in general have had too damn much high frequency content (in my opinion) for decades now. MOST condenser mics used in recording, even for classical and other acoustic music, have a rising high end response. CD first in the 80s (remember how piercingly bright that sounded at first?), and now digital radio lets us hear how bad it actually is.

Add 6-8db of hf boost to a recording, then broadcast it on analog fm, with the processor settings typically used to prevent overmodulation, and keep average audio high enough to be "useful" and above the noise floor, and it (the recording with boosted highs) won't sound that different from the same recording without the hf boost broadcast the same way. The multiband limiter will register this boosted hf content as "too much" and simply turn it down. Broadcast the recording with hf boost on HD, and you'll hear it alright. And it'll burn through your eardrums, straight through to the grey matter!

HD actually lets us hear what's wrong with recordings...not analog's strong-suit.

 

[Tom Wells]

I am comparing the sound of violins on HD FM to live violins. I agree that the announcer (was it WDAV?) sounded well balanced
and not overly sibilant.
I am suggesting that it makes the violins sound like they are using some new kind of bow rosin that contains "screechy grit".
A VERY fine grain grit, but still, something is wrong with the "edge" on the sound of those violins...

We normally experience dropoff of high-frequency info from sound sources, and our brain uses these cues to determine location and direction, or whether something is between us and the sound source, etc.

The brightness of HD is a bit too much "right there in my face", versus the softly "degraded" analog.

Most of us do not wish to experience the full dynamic range of music. We accept the limited range of a radio at a normal volume,
and prefer this compression to the volume level of everything being played at original levels.

The naturalness of the compression and balance of tones at lower volumes is far more important to a good radio result than
exercising the full dynamic range.

Of course I'm not saying it can't be made to sound right, just that right now it's a little bit "realer than real", which,
like artificially augmented body parts, is attractive in a curious way, but ultimately unsatisfying.

 

[Mike Walker]

And I'm telling you that it is the RECORDINGS that are bright! HD is letting you hear that. Whenever anybody hears ANYTHING with compressed digital, they assume it's the codec. Usually it isn't...usually the exact same effect can be heard on the uncompressed original, if one has access to it. How often do you listen to classical cds? They're (often these days) RIDICULOUSLY bright (as is most other recorded music).

I don't mean to yell or lecture, Tom. Obviously you're very knowledgable in engineering. But I have found that engineers are often poor LISTENERS (not that YOU are...but often they are. Don't take that too hard...most people are poor listeners. For the record jocks are worse than engineers, program directors are worse than jocks, and general managers have no concept of what radio should sound like to begin with...particularly if they came up through sales. So who is a qualified listener? I AM OF COURSE (KIDDING!) Seriously, if you believe that lossy compression causes recordings to sound brighter, with "too much rosin" on the strings, THAT IS WHAT YOU WILL HEAR unless the test is done double-blind. It's the nature of the human beast, and we are ALL succeptible.

So how do I KNOW that lossy compression schemes are much better than most people think? Because I've done numerous "null" tests...compressing a recording, then laying it down (with polarity inverted) on top of the original in an editor. If both (compressed and uncompressed) are identical, the result will be zero output...silence (100 percent plus -100 percent equals 0). With a good codec, and adequate bandwidth, they cancel each other almost completely. What's left is what the codec removed. And it's almost nothing. Try it yourself, you'll see (if you have a codec that returns the exact same number of samples after encoding! If not, the two files won't line up).

 

[Mike Walker]

The problem is that you're comparing HD to violins in a live performance (as you've said). But when you attend a live performance, you sit in the audience (duh). As you also pointed out, highs decrease with distance. So if you listen, and don't hear a true representation of a live performance, it's the fault of HD, right? WRONG! HD is VERY ACCURATELY reproducing what a live performance sounds like...from INCHES (in the case of soloists), or a very few feet (in the case of a string section) away. THAT Is how most recordings are made. It doesn't sound like a live performance TO YOU, because you weren't suspended in air a few feet above the violins. In fact (shame on you, Tom), you didn't have a separate "ear" suspended a few feet above EVERY section of the orchestra...again, INCHES away for soloists. YOUR FAULT TOM, obviously!

Then take the excessively bright microphones (condensers with rising high ends) used for most recordings these days...and you have EARBLEED if the recording is ever reproduced as it actually exists (rather than the softened highs we get with analog fm and to a lesser extent with vinyl). This problem can only be truly "solved" at the recording end...move the freakin' mics back at least behind the conductor...preferably a fair distance behind him/her, and using minimalist mic techniques...preferably TWO mics, but if you're using spaced omnis, you might get OK results with a third for center-fill. FORGET "SPOTLIGHT" mics for soloists. Balancing is the CONDUCTOR'S JOB! If you can't hear a soloist well enough, the conductor isn't doing it (his job!)

Extra "rosin" on the bows? Hell, many recordings sound like a drill going straight through the eardrums, into the brain! Not HD's fault. My 2 cents worth, yours for free.

 

[PhilJSmith67]

Geesh... Imagine how much live-performance recordings would suck if only two microphones were used, aimed at opposing 80° angles to the performers (human ears!), from a location toward the right side of Row CC.

I'll vote to stick with the "unnatural" setup with microphones near each instrument and vocalist, with a well-paid dude working the sliders near the back-center of the venue!

 

[R.F. Burns]

Geesh... Imagine how much live-performance recordings would suck if only two microphones were used, aimed at opposing 80° angles to the performers (human ears!), from a location toward the right side of Row CC.

I'll vote to stick with the "unnatural" setup with microphones near each instrument and vocalist, with a well-paid dude working the sliders near the back-center of the venue!

Then you disagree with Telarc and the Mercury living pressence system who believe it's the job of the conductor to control the mix as opposed to a 3rd party producer sitting in a booth.

 

[Mike Walker]

Exactly RF. If the balance isn't right where you set the microphones, MOVE THE MICROPHONES (or the venue). Don't add more microphones. Balancing the sound is the conductor's job, not the engineer and/or producer. This is THE way to record acoustic music...in particular orchestral music. And, as RF mentioned, it produces STUNNING results (again...as with the recordings from Mercury Living Presence, Telarc, etc.)

We've all gotten used to the supply of microphones, and recorded tracks being nearly infinite. But there was a time when it wasn't so. And ya' know what? Some of the most stunningly natural recordings ever made come from the early days of stereo, with minimalist micing techniques, and two (or three as in the case of Mercury) tracks.

Now when it comes to rock, pop, country, etc...music with electronic instruments, I'm not such a purist, because there was never an "acoustic soundscape" if you will to preserve. Acoustic instruments in a hall with good acoustics are a different matter. Capture what's there...no editorializing.

 

[PhilJSmith67]

Then you disagree with Telarc and the Mercury living pressence system who believe it's the job of the conductor to control the mix as opposed to a 3rd party producer sitting in a booth.

No, I'm not disagreeing with that. I think that is also very effective, and make the actual live performance sound balanced, as well.