Data dearth dooming digital radio?

[radioskeptic]

I recommend the following editorial from Stereophile: “Data Density Eats Tweaks for Breakfast” http://stereophile.com/asweseeit/data_density_eats_tweaks_for_breakfast/

The writer sees the prospect of uncompressed 24-bit, 96-kc digital audio (or 24/96 for short) over the web as promising a revival of interest in high-end audio. Compare that with 16/44.1 on CD’s

We all know that while the music on CD’s emerges from a background of utter silence, the resolution isn’t there. (If you doubt that, just play a good vinyl copy of any pop song with a fade-out ending, and crank up the volume as the music fades out. Yes, there’ll be audible surface noise and rumble, but the music itself will sound extremely clean—perhaps even cleaner than it sounded before the fade-out began, because it’s much easier for the stylus to track those small modulations of the groove. Now try that with a CD copy of the same recording, and you’ll hear how the sound gets rougher and rougher when you crank it up as the level on the CD goes down. That’s what I mean by resolution!)

And both internet audio and over-the-air digital audio, thanks to lossy codecs, have much lower resolution than CD’s.

But 24/96 digital would sound like more like a pristine LP or a master (analog) tape--but without hiss, rumble, wow-and-flutter or surface noise.

Go read that editorial (it’s under 1,000 words), and then consider these two points:

First, improved home internet, especially with fiber optics, will soon enable the streaming of 24/96 digital for listening in real-time (and perhaps even faster for saving files). But wireless internet will never have the bandwidth to handle files like that without heavy, lossy compression. (Low-powered wireless home routers eventually will have that kind of bandwidth, but high-powered wireless for mobile applications probably never will. There just isn’t that much bandwidth in the spectrum.)

And second, portable music players won’t be limited to MP3’s for long. Chip capacity will improve, and higher resolution formats will be practical in the next generation of players. Bandwidth is irrelevant here. But that doesn’t apply to mobile streamed audio.

I think the implications are that (1) both webcasters and broadcasters who stream will eventually be obliged to provide a high-quality 24/96 stream for home users, in addition to the choice of 64k or 32k compressed streams many do now; (2) the compressed streams will be used mainly for mobile listening; and (3) as portable players with a huge data capacity proliferate, there will be much less mobile listening to streamed music content, and most radio and internet radio listening on the wireless web will be to spoken word content—all-news, news-and-info (like NPR), talk, and sports.

And what I said about the implications for streamed music on the web also applies to digital radio in all its forms, “HD,” FM Extra, DAB and DAB+ alike—but not to analog FM, which has excellent resolution.

Finally, I think the availability of very high resolution audio on the web will be the coup de grace for the record industry. Could they really market audio-only blue rays as the new CD’s? No, they won’t be around much longer. (Are you listening, Gordon “Neville Chamberlain” Smith?)

Comments?

 

[local oscillator]

Skpetic, I think you've made the argument perfectly for why a high-resolution, no-noise digital audio signal modulating a very low-noise analog RF signal (FM done properly!) is a music transmission system that can't be beaten.

 

[tomservo]

I'll tell you why FM can be beaten. Frequency response. There's something about the harsh brickwall filter for the stereo pilot that makes FM sound 'harsh' to me. A well processed AM station is easier to listen to, at least with my ears. But those well processed wide AM'ers are all but gone. The truth of the matter is, most of us can still hear beyond 18 kHz or wherever that FM cutoff is.

While I would love to cheerlead the movement to 24/96 audio, I gotta say this: SACD has been a commercial failure. DVD-A has been a commercial failure.

The general population has roundly rejected high resolution audio, but has embraced poor production, lossy compression and $10 Wal-Mart earbuds on a tiny music player as the defacto listening system. I don't see 24/96 audio as been a boon for anyone beyond serious audiophiles and a few narrow genres of music.

FWIW, I just recently downloaded a swath of lossless 24/96 demo audio from a number of sites just to see if my sound card would play the audio. 24/96 yes, 24/192 was hit and miss. I don't have a high end card or setup, so I doubt I was getting the full effect, but it WAS different, but only really noticeable on certain types of music like percussion and then only after doing an A/B comparison with a 16/44. Still, if I could have all my new music delivered in higher resolution, I'd take it. My mp3 player supports mp3, m4a, ogg, wav, flac and more at up to 24/96, so adding those files to my playlist is no problem.

 

[K6JHU]

I have always lamented that in the old days (LP) the audio discussion was always "How much separation? what is S/N ratio? What is the harmonic distortion?" Now it is "What color is it and how many songs does it hold?"

 

[radioskeptic]

you hearIn Reply # 1, Local Oscillator said,

Skpetic, I think you've made the argument perfectly for why a high-resolution, no-noise digital audio signal modulating a very low-noise analog RF signal (FM done properly!) is a music transmission system that can't be beaten.

Thanks for the vote of confidence, L.O., but I wasn’t talking about using FM to carry a digital signal as a subcarrier. That’s what FM Extra does, and it works better—and sounds better—that the FM version of “HD” (the less said about the AM version, the better!). But FM Extra has little data capacity, and thus it, too, uses a lossy codec. The AAC+ codec sounds much better than the proprietary “HD” codec, but it still throws away a lot of data.

You can’t get 16/44.1 into much less than 1.5 Mc bandwidth. Remember, the most successful digital audio recorders used helical scan heads (like those in analog video recorders) for a reason.

No, I was talking about just plain audio on FM, because FM itself has virtually infinite resolution. And that brings us to what Zach (replying to L.O.) said in Reply # 2:

I'll tell you why FM can be beaten. Frequency response. There's something about the harsh brickwall filter for the stereo pilot that makes FM sound 'harsh' to me. A well processed AM station is easier to listen to, at least with my ears. But those well processed wide AM'ers are all but gone. The truth of the matter is, most of us can still hear beyond 18 kHz or wherever that FM cutoff is.

The wide AM’s are all but gone? No, I’m afraid they’re completely gone. Even the non-IBOC’ers are limited to 10-kc audio these days by FCC fiat. And that’s significantly lower than FM’s, which are limited to 15 (not 18) kc. So how could any AM today sound as good as FM? Simple. Too many FM stations are butchering their audio with bad EQ and excessive compression. (If even the better public stations sound worse than AM, maybe it’s your FM receiver.)

And why is FM audio limited to 15 kc? It’s to accommodate the 19-kc pilot tone that (1) automatically switches a stereo receiver to stereo and (2) is doubled to replace the suppressed 38-kc carrier of the stereo difference signal (that same 19-kc, whatever its instantaneous error, is doubled at the station and used to feed the balanced modulator that gives you the L-R signal between 23 and 53 kc; for that reason, you never get the grotesque sound that results in SSB reception of Ham and CB radio because the replacement carrier is not exactly the same frequency as the one suppressed at the transmitter; of course, with DSB, it would be even weirder—something like the Daleks’ voices on Dr. Who).

I agree that mono FM sounded purer, but it really isn’t that big a compromise, even for those of us who can hear well above 15 kc. (And yes, I can hear the 19-kc pilot when I put a jumper in my tuner so that it goes to the amplifier! It sounds like the flyback whistle you used to hear from vacuum tube TV's, only about a minor third higher.)

 

[TSL2]

I'll tell you why FM can be beaten. Frequency response. There's something about the harsh brickwall filter for the stereo pilot that makes FM sound 'harsh' to me.

That's processing and playing the loudest game! Stupid If radio really thought listeners wanted a better sound they'd improve/remove processing


The general population has roundly rejected high resolution audio, but has embraced poor production, lossy compression and $10 Wal-Mart earbuds on a tiny music player as the defacto listening system. I don't see 24/96 audio as been a boon for anyone beyond serious audiophiles and a few narrow genres of music.

It's somewhat about quality. It's 100% about playing what I want when I want. HD can't do that, HD is still about playing a strangers playlist with commercials. That game is over.

 

[Chuck]

I think the public has already voted about high resolution audio. Most people wouldn't recognize high quality audio if it bit them in the a$$. Why do you think Wal-Mart sells a ton of "surround sound" receivers - complete with speakers and subwoofer - for $89.99? It is not about quality.

It is my observation that the few people who have heard about HD think it means artist and song title display on their radio. Of course, that can be done with RDS/RDBS, which is cheap and easy to implement.