On 1/17/12 01:45 , Dave Barnett wrote:
On 1/15/2012 9:33 AM, SMS wrote:
If you look at table 5.2.1 at
http://www.nrscstandards.org/DRB/Non-NRSC%20reports/NPRmultiple_bit_rate_report.pdf

you can actually learn where listeners begin to not like the audio
quality.

If you look at section 2.2 of that paper you'll find that Ibiquity
controlled the audio samples used in that test. The "digital" signal fed
to the participants was the output of a CD player with the level
carefully controlled and run through the Ibiquity codec with no other
audio processing whatsoever. The "analog" signal was run through an
Omnia 6EX and an Optimod 8400 where it was compressed (in the analog
domain, I'm speaking of now).


Is it any wonder that people felt the HD signal had superior audio
quality? Things don't sound so good when you squash the dynamic range.
So this is just a classic case of the fox guarding the henhouse, isn't it.

Dave B.

What's also not being addressed, is that stations are also processing
the dynamics on the HD streams. Like record companies do with CD audio.
Like ITunes does with MP3's. The way nearly all web audio, and satellite
radio audio is processed.

The comparison between processed and unprocessed audio in these
demonstrations implies that what will be heard on the air is, in fact,
unprocessed audio.

This is not the case.

So, virtually from the moment of implementation, HD radio fails to
live up to the promise.