[BC] Hearing artifacts from digital formats

[orban@earthlink.net]

At 11:48 AM 10/16/2005, you wrote:
>From: "Bill Sepmeier" <dcpowerandlight at hotmail.com>
>Subject: RE: [BC] Digital Radio in Australia - Progress??
>To: broadcast at radiolists.net
>Message-ID: <BAY107-F219E0B079D10F3EB2CB151A27F0 at phx.gbl>
>Content-Type: text/plain; format=flowed
>
>
> >>
> >>So how's 128kbps MP2 going to sound compared to 96kbps "HD"Radio?
> >
> >The HDC codec at 96 kbps will sound far better than MP2 at 128 kbps, which
> >dangerously close to the edge of where MP2 falls apart into gross
> >distortion.
>
>Having installed over 300 128kbps MPEG-2 satellite networks worldwide, many
>of which you probably listen to daily without knowing it, I challenge this
>assertion totally.  Please present your supporting evidence, if you have
>anything other than supposed and anonymous "complaints" about Eureka or
>trade press "studies" presented by "HD" proponants trying to sell their
>monopoly ideas.

As bit rates fall, MP2 degrades much less gracefully than later 
codecs like MP3 or AAC. The latter codecs sound phasey and watery and 
start to lose HF response, while MP2 sounds dull and unpleasantly 
distorted (sort of like a clipping amplifier). This tends to happen 
to MP2 at about 96 kbps.

My post represents my opinion, based on my own listening and on 
others' opinions, as well as the original 1995 NRSC CRC-supervised 
listening tests when MP2 was a contender for the IBOC codec and in 
which I was one of the listeners scoring the codecs. Beyond that, I 
recall some AES publications. However, I am not going to spend all 
day chasing down chapter and verse for you; I've got other things to 
do. Google is your friend.

If you have 128 kbps to play with, then the best codec choice is AAC 
IMO. I don't know why anyone would build a digital radio system in 
the year 2005 that uses the MP2 codec.


Bob Orban