[BC] Digital Intgerference (was AM Interference)

[Rich Wood]

------ At 11:06 AM 12/18/2005, Cornelius Gould wrote: -------

>Are they using coded material on the Hard Drive system, or the STL (or both)?

Most stations I've seen don't use uncompressed files on their digital 
systems, even though disk space is incredibly cheap. Most I've seen 
use compressed digital STLs.

Many stations receive spots and programming in MP3. I'm part of an 
MP3 distribution network called Radio-Studio.net. MP3 between 192 and 
320KBPS are very common sources. In Talk we use remote units that 
either use dialup at 33,300 or ISDN. Each uses a codec. Satellite 
delivery uses a codec.

Essentially, what we're doing is replacing analog generational losses 
with codec losses. Analog losses are easier to accept. It's usually 
constant tape hiss that the ear gradually tunes out. Codec artifacts 
are transient and repeatedly call attention to themselves.

>If so, this can account for the artifacting you hear.  My experience 
>so far is that at 96 kBPS, it's really hard to pick out 
>artifacts...at 48 kBPS, they are there...about on average to the 
>typical mp3 @ 128KBPS files I hear.  This assumes a purely linear 
>audio source on Hard Drive & STL link.

I haven't seen an installation like that in a long time. Our future 
will be littered with codecs everywhere.

>Anyway, the HD Radio codec doesn't seem very tolerant of pre-bit 
>reduced  material to my ear.

Then we have a systemic problem that goes far beyond the IBUZ artifact problem.

Rich


Rich Wood
Rich Wood Multimedia
Phone: 413-303-9084
FAX: 413-480-0010