iSuppli’s forecast of U.S. digital radio shipments for HD Radio

[davideduardo]

According to the USA Today article, HD Radio has been around since 2002:

Untill 5 days ago, HD was not even authorized by the FCC except in experimental transmissions. The marketing for consumers swtarted 9 months ago, when the HD Consortium felt there were enough stations on the air to make it work. So the consumer perspective is that it started in June, 2006.

 

[Mike Walker]

"Old analog radios ain't bad", huh? Well my first girlfriend wasn't "bad" (no matter how hard I tried to convince her to be!) My wife is better.

Analog fm stereo has a noise level comparable (at best) to a quiet analog tape, and at worst to someone trying to talk over the constant sound of running water. High frequencies are limited to somewhere between 15khz and 17khz. No big deal. What IS a big deal is that the 75us pre-emphasis/de-emphasis curve means that stations can either be loud, or they can be bright and clean. They can't be both. Classical stations choose bright/clean. Everyone else chooses loud. ALL sound dull in comparison to the original, or to the HD stream. "Good" analog FM stereo has a channel separation of 50 or so db. With HD it's 90db or more. Distortion on analog FM can be several orders of magnitude higher than HD. Etc.

To those of us who are actually "into" audio, these things make a difference. "Not bad" ain't good enough. As for the satellite radio comparison, people don't buy satellite radio (or largely HD) for sound quality, anyhow (other than the very picky...largely public radio listeners like me...and early adopters) They buy for the improved variety. I get formats that I can't get otherwise (Exponential Radio from NPR as broadcast on WFAE Charlotte's HD2 stream is WONDERFUL for people who are actually into music and want to hear some freakin' variety...not just the same damn hits. Plus other HD2 streams in my area have formats just not available in my market (country oldies, 70s pop/adult contemporary, etc) Certainly enough to justify the 100 bucks I spent for the radio, and thirty for the antenna.

 

[radioskeptic]

Mike, do you really think that 90 dB of stereo separation is of any practical use? On real stereo programming, that is?

Most stereo pickups (yes, for vinyl!) has separation of only 30-35 dB at midband, and less at the extremes of the audio spectrum. First generation pickups had only about 20-25 dB at midband. And in a real listening environment, masking of the weaker sound from one speaker by a 30-dB stronger version from the other makes that irrelevant.

And as for 75-μsec pre-emphasis? Well, it seemed like a good idea at the time it was made a standard part of the mono FM system. Unlike AM, FM has a triangular noise spectrum, meaning that noise increases with frequency. While HF audio noise can be negligible on strong local station, reception of weak stations be plagued by a white noise heavily weighted toward the treble end of the spectrum. De-emphasis in receivers reduces that noise as it cuts the pre-emphasized treble back down to size.

Unfortunately, it doesn’t really help with Zenith FM stereo, because the difference subcarrier is (1) double sideband suppressed carrier (i.e., AM sans carrier) and (2) in the noisier part spectrum recovered from the detected FM signal.

This also explains why the “white noise” in stereo (which disappears if you switch to mono) has a different spectral content, with less treble, but more midrange and bass: FM noise components with frequencies at or near the (suppressed) carrier (38 kc) are around 10 dB higher than those at 3.8 kc in the mono (L+R) audio (and that frequency is just about the peak of the ear’s sensitivitiy), and those noise components in the FM signal are detected as bass noise components in the demodulated L-R difference signal. The noise across the 23-53-kc range of the difference subcarrier varies only by about 8 dB, so the detected AM noise is almost flat, but the same de-emphasis used on the straight mono audio gives it a roll-off, resulting in the dull roar of stereo white noise.

Good FM stereo should sound almost exactly like the original, except for a VERY slight treble roll-off that is audible ONLY on the highest-quality speaker systems. Stations that choose to be as loud as possible at the expense of any semblance of fidelity do indeed sound dull, as you said. But that’s their own fault for making an unwise choice. The problem is not with pre-emphasis, but with the judgement – and dare I say the taste (or lack or it) –of the morons running most of the stations!

 

[Mike Walker]

Yeah good fm SHOULD sound that way. And does on mostly small market stations with clean signal paths, but who aren't in a modulation war like the "big guys". 75us pre-emphasis is EXTREME as frequency rises. You simply can't boost highs that much, AND be loud, AND bright. Something's gotta' give, and that something is crispness.

No I don't think separation beyond 30-40db makes much difference with much material. But it IS an advantage of digital, so why not tout it? To not point out that this spec is FAR better would be an injustice, even if it makes far less difference than other measured specs...like distortion, flat frequency response even at full modulation, and distortion that doesn't rise to extreme levels under multipath conditions. THOSE are the big advantages. Separation just goes "along for the ride". Hell on a 32" tv from ten feet away, most people see NO difference between 720 and 1080 lines. But if your display HAS 1080 lines, that still is a higher spec, so why not crow about it? All other things being equal, expanding quality far beyond what it absolutely has to be is a good thing. The "fi" IS higher.

Radioskeptic,we both grew up in an era when FM stereo sounded better than it does now (at least I believe you're an "old fart" like me). Ride through a small market where the local station is owned by a guy who cares about sound, and you'll get a glimpse into the past! But it ain't goin' back. The modulation wars on analog won't go away. HD gives those of us who care about sound quality a chance to have sound that's BRIGHT and clean, even when compressed and clipped TOO DAMN MUCH! Even public stations have an excellent reason to use more dynamic-range compression than any audiophile would condone...road noise in cars, and analog noise from...well the world. Every db in average modulation is a db less perceived noise. Also if you're a public station, it is to your advantage that your signal not simply disappear when someone tunes from the local hit-music station to yours!

Show me a station where the on-air audio sounds just like a cd (or lp), and I'll show you a PD who's about to scream at his engineer because his station isn't as loud as the competition. And the PD isn't entirely off base! People DO perceive stations that "jump off the dial" as being "bigger", and more "powerful". It also enables listening at work, with the volume turned down low...because quiet sounds don't disappear. NOBODY at work is going to turn the volume down when someone speaks to them, or they answer the phone, and back up to hear quiet passages. They'll simply change to a station with more consistent levels.

Dream in an ideal world, LIVE (and work) in this one!

 

[PhilJSmith67]

Mike, I have a home experience with loudness and high compression equating with "sounding more powerful." I have a micro-powered Part-15 which is hardly more than WinAMP running on a server machine, with a load of my CD selections ripped at 256 or 320 kbps MP3. My wife and I tune it on a fairly cheap FM radio while getting ready for work.

About a year ago I stumbled across a nice compression/expansion/limiter plugin that works surprisingly well. I set the single-band portion of the plugin to significantly compress the audio so quiet passages/content wasn't so darn quiet. I set up the multi-band section to maintain similar bass/midrange from song to song, while keeping the highs clean with sharper attack/decay rates. My wife said it sounded MUCH better and she could hear the station farther away. In reality, it sounded vastly different than the "true" sound with the plugin turned off. And, obviously FM stations don't gain distance with higher compression or modulation.

If I listened to my flea-powered station at very high volume levels, I would prefer to run "barefoot" without the plugin so I can enjoy 30 or 40dB of dynamic range, but I rarely listen that way. I suspect that most radio listening is done at moderate or lower levels, where compression helps overcome environmental noise.

 

[Mike Walker]

You're right that FM stations don't gain ACTUAL distance with higher modulation the way AMs do. But they do gain EFFECTIVE distance...because the noise level is fixed...what's there is there. Increasing average modulation by ten db means that you can turn the volume on your radio DOWN ten db...thus turning the noise down by 10db...then you can go farther away from the station and still have a listenable signal (because the noise will become bothersome at a greater distance)...thus increasing EFFECTIVE coverage.

It's all about noise versus signal (in analog). The higher the ratio of signal (audio) to noise...in other words, the greater you can raise that average volume level...the lower the perceived noise...and the farther you can get from the tower before noise again rises to a bothersome level.

I've used DSP plug-ins with winamp, too. Great for background listening. I have a three band limiter program from db Audioware, a British company...sounds just like a well processed FM station when you crank the compression/limiting up to about 12db.

 

[PhilJSmith67]

But they do gain EFFECTIVE distance...

Agreed...

 

[paul vincent zecchino]

Audio quality was never the issue. As with the rest of TeamBLOC's manipulations, it's a contrived problem for which HD Stooge-radio offers a most restrictive, destructive, and best of all - for KronyKasters - extortionately costly non-solution.

Dr. Paul Vincent Zecchino
Manasota Key, Florida
30 March, 2007

 

[paul vincent zecchino]

PS -

Peter Lynch recommends that those wishing to buy stocks in retail companies visit local malls, note which stores are busy, and which aren't.

Bridge figures may only tell half the story. Reports from around the country indicate HD receiver sales are, ahem, sluggish. Compounding this, is the fact retailers are increasingly wary of selling them, as customers frequently return them.

Now TeamBLOC blames 'poor tuners', 'weak tuners' for their 'HD Trollout' flop?

Aren't they predictable? It's the receiver manufacturer's fault, right?

How can that be? HD sets are made by good companies, well versed in producing successful receiver lines.

Might they be, as are citizens, limited by a poorly conceived, half-baked, sloppily executed, long obsolete, fatally flawed, serially superseded, kleptocratic 90s pipe dream?

Receiver returns render HD sales figures moot.


Dr. Paul Vincent Zecchino
Manasota Key, Florida
30 March, 2007

 

[clouseau]

..TeamBLOC's manipulations,

HD Stooge-radio

KronyKasters

extortionately costly.

Dr. Paul Vincent Zecchino

Along time ago, Jackson Browne recorded a song called "Doctor, My Eyes."

More like "Doctor My A##"


Clouseau

 

[paul vincent zecchino]

Jackson Browne? Doctor My A#*?

I like it! Thanks!

Pithy, albeit anachronistic!

Dr. Paul Vincent Zecchino
Manasota Key, Florida
31 March, 2007