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Old August 14th 03, 06:07 PM
Dexter J
 
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Salutations:

WBRW wrote:

Take a listen to the AM Stereo airchecks on this site:

http://www.1240keva.com/airchecks/

KEVA is an 880-watt Class C station in Evanston, Wyoming, using a
vintage McMartin vacuum tube (valve) transmitter and a complete
1983-era audio chain: a CRL AM Stereo Preparation Processor, a CRL AM
Stereo Maxtrix Processor, and a Motorola C-Quam AM Stereo Exciter.

The audio in the MP3 clips was recorded from KEVA's Motorola AM Stereo
Modulation Monitor, so you are hearing KEVA exactly as they sound on
the air -- not from a direct feed from their audio board.

Now, for those of you who have heard IBOC or DRM... can digital AM
ever sound this good? I don't think so... there's only so much
quality you can squeeze out of a 20 to 36 kbps data stream. At this
point, neither IBOC nor DRM have managed to eliminate the swishy,
gritty, phasey, heavily artifacted "28.8K RealAudio Web-Cast" type of
sound from their digital audio. And except for a MAJOR revolution in
the science of "lossy" audio compression, I don't think they ever
will.

Digital does have its advantages... but not in AM audio quality!


I agree broadly with your conclusions regarding IBOC/DRM - however - you
are incorrect in labelling low kbps RealAudio as being completely awful..
It depends on the site specification regarding the codex and how carefully
the site administrator works on the sound objects/transaction model prior
to conversion..

I'm generating very close to AM stereo quality RealAudio at fixed 20kbs
without that 'bottom of the well' sound or any buffer problems on low speed
connections world-wide - have a poke around the site below.. I run 40-45
streams per 1mbs of outbound pipe and still feed a general site through the
same server head..

I have picked up a number of wireless/mobile users over the past year given
that my feed doesn't overload their available bandwidth at the CPU while
still providing a pretty sound quality at G2+ and I have been suggesting on
and off that WiFi may provide for a better over all software based receiver
model.. I can do the same with video feeds - but that limits the feeds to
about 20 streams per 1mbs or pipe and advanced Flash/SMIL falls somewhere
around 30 feeds per 1mbs outbound..

I apologize and say again that I'm not really a RealAudio zealot or
anything - I can't even get them to list my little bitcaster on their
site.. But credit where it is due - it's a pretty good codex and
multi-media streaming solution overall.. Broadly ported to *many* operating
systems and codex too..

I wonder now if the same model applies to IBOC/DRM.. Can you force minimum
kbps before accepting transmission as viable? If so - does it improve the
quality at the receiver head while limiting some of the problems you have
outlined?

A LOT of the complaints related to RealAudio have MUCH more to do with
bitcasters cheaping out, not really understanding the details at the
server/codex or trying to mess around client side for the marketing bulls
rather than anything particularly wrong with the particular multi-media
solution itself..

--

J Dexter - webmaster - http://www.dexterdyne.org/
all tunes - no cookies no subscription no weather no ads
no news no phone in - RealAudio 8+ Required - all the Time

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