On Sep 30, 2:50 am, SFTV_troy wrote:
Tom wrote:
On Sep 29, 7:22 pm, SFTV_troy wrote:

The quality stinks? Really? I listen to XM streams via the internet,
and they sound just fine. Is there really that huge of a difference
between Internet and Mobile Receiver?

DRM (and I imagine HDradio-IBOC-AM) are fatiguing (to some people)
because very low audio encoding bitrates must be employed in order to
fit within the allowed spectrum; typically 10kHz of RF spectrum
restricts the audio to perhaps 20kbps. Considering that a CD streams
at about 75 times this rate, losses in encoding at these very low bit
rates along with the consequent artefacts are pretty severe.

True.

On the other hand, codecs have advanced a lot over the last few years,
specifically to improve low bit rates. Take a quick listen to these
AAC+SBR stations:

Q93 Louisiana -www.shoutcast.com/sbin/shoutcast-playlist.pls?rn=377155&file=filename...
SKY FM -www.shoutcast.com/sbin/shoutcast-playlist.pls?rn=8849&file=filename.pls

IMHO they sound better than the AM Stereo radio in my car. Even as
low as 16 kbps, you have fairly good sound. (If the above link did
not work, here's the station listing.)http://www.shoutcast.com/directory/i...&sgenre=Top%20...

Also:

With a nominal increase (+5 khz each side),
HD and DMR can achieve 40 or 70 kbps
which is as good as FM.

I was too general in my comment about satellite radio. Both XM and
Sirius use a range of encoding standards, putting news/talk on the
lowest and music on the highest. My main channel on Sirius Canada is
CBC Radio One which was stupidly assigned a news/talk standard when it
actually comprises an eclectic mix of content - we're currently
listening to Randy Bachman (BTO) playing #2 hits from the 60's and
70's in his weekly 3-hour program from the local FM. The Sirius news/
talk encoding is not much higher than 20kbps - voice is bad enough but
music really stinks. .....

I don't know much about the Satellite services, but I see sirius uses
AAC (no plus). AAC is not much better than MP3, and 20 kbps is
definitely not sufficient, even for voice. I'd probably be calling
every day, and complaining to sirius, until they got tired of hearing
from me.

.... What you hear over
the Internet will be encoded differently, using codecs popular for
Internet streaming, not their proprietary ones for satellite delivery.

Ahhh I see. I figured they'd use the same codec, rather than spend
money creating two separate streams for the satellite and the net.

I've been listening on the internet, and considering subscribing, but
if the radio's sound is crap then it's not worth the $13 a month fee.
(later). Ooops hold on. If wikipedia is accurate, XM is using the
superior AAC+. "Audio channels on XM are digitally compressed using
the aacPlus codec". So XM would sound as good as internet.

HD/IBOC does not employ AAC, although an earlier version may have
IIRC. It uses something called PAC(?)

One annoying thing I always found about either service was that even
with a satellite dish the sets at Wal-Mart broke up on and off as you
moved around them. How QUAINT.