Jun 16, 2005

NPR’s Day to Day ran a feature on Sonare Technologies’ Babble voice privacy device (which, contrary to some beliefs), does not involve sound cancellation techniques.

The NPR talks about Sonare’s philosophy of “sound as an element of design.” It’s a philosophy worthy of debate. Absorbing and blocking sound can be expensive, and as the NPR feature notes, we as humans do need some sort of aural stimulus (spend time in an anechoic or very quiet environment and you’ll see what I mean). But Babble resolves privacy issues by increasing sound levels, just like a masking system. Is this a good thing?

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Wired News: Sagging Radio Plays Digital Card

“Radio knows that it needs to make that jump to the digital universe,” said Tom Taylor, editor of the daily newsletter Inside Radio, which is published by a division of Clear Channel Communications. “Radio sees it as a journey it has to make to reach continued growth and viability, and a chance to have additional stations, serve listeners and make more money.”

This is a timely article, given the recent BAS presentation on digital radio at WFCR at UMass Amherst. Charles Dubé and Richard Malawista shared their experiences with digital radio at WFCR and the discussion was enlightening. One thing they pointed out was that the big radio conglomerates were embracing digital radio because they are hoping that the world “digital” would help stem their ratings slide - of course these conglomerates apparently don’t think that commercial radio’s limited playlist (which basically consists of “50 Cent”, “NORE”, “Eminem”, “More 50 Cent”, “Christina Aguilera”, “Repeat 50 times”) has anything to do with the declining audience. Sigh.

One thing we were told during the presentation was that some in the digital radio industry need to downplay the expectations of CD-quality from digital radio since, at 96 kbs and 15 kHz bandwidth, iBiquity’s HD Radio is nowhere near CD-quality (but it still sounds better than analog FM). Apparently not everyone got the message. From the article:

“FM is going to sound like CDs, and AM will sound like today’s FM,” Struble said. “You’ll eliminate the static and hiss and pops, which will become a thing of the past because of digital processing.”

You’ve got to love marketing. At least DRM isn’t part of the HD Radio spec (but I forgot to ask about “broadcast flag”-type copy control).

The audio stream uses an AAC-based lossy compression. Because we are talking about audio streams, HD-Radio’s will have to ‘buffer’ their streams for a few seconds before playing digital audio, just like we see with Real Audio/WMA streaming audio in web browsers. HD Radio stations will compensate for this by playing normal analog radio when you first tune to a station. When the radio has buffered enough data, the radio will switch to digital audio. The buffered audio has another downside - because of the buffering delay, digital audio won’t be real time. When you NPR station announces that it’s 8:00am, the time will really be 8:00:08am. The analog feed will also be used as a fall-back signal in case the digital signal gets too weak (at the edge of the broadcast area for instance).

Because we’re talking about radio, we still have to deal with added audio compression. Theoretically HD Radio could transmit raw audio without compression, but that would lead to frustration for listeners in cars or in noise-sensitive environment. One BAS member made a suggestion that HD should transmit the raw feed with a subchannel containing compression instructions, and then let the client radio perform the (optional) compression. I love this idea, but given that the format is fixed, it’s not gonna happen.

I’m also disappointed that the maximum bit-rate is fixed at 96 kbs. From what I understand, this value was chosen because a) higher bitrates might interfere with analog FM channels, and b) listening tests showed that 96 kbs was “good enough.” I would have preferred to see a much higher maximum bit-rate (perhaps 320 kbs), with an interim limit of 96 kbs. That way, there is an option to increase the bit rate in the future. With the current U.S. HD Radio format, we can’t do that without revamping the format (and buying new transmission equipment and radio receivers). Oh Well.

But all in all, HD Radio is a good thing. I especially like the subchannel option which will hopefully give us some additional entertainment and informational listening options.

[Tag: Digital Radio]

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Struggling DC-3 had prompted complaints from residents near airport: “They say the DC-3 cargo plane that routinely flew over their Fort Lauderdale neighborhood often was too low, too loud, too labored.”

In trying to convince potential clients that noise analyses could help detect mechanical problems and reduce maintenance costs, a former boss of mine used this axiom: “if you can hear it, it’s costing you money.”

Maybe they saying should be “if you can hear it, it might kill you.”

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The BBC is offering free downloads BBC Philharmonic performances of Beethoven pieces.

I wish they had told me this before… At least I can look forward to downloading Symphony 6 and 9 in the future.

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Some people have way too much time on their hands.

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