Regarding “BMC Hopeful About EXB Band Proposal” (Sept. 22 issue):
Most current audio distribution mechanisms offer a system of scaled quality, i.e., from what is, or at least passes for, a perfect duplicate of CD-quality (i.e., if not linear, then at least stereo AAC encoding at 128 kbps or better) … all the way down to mono 10 kbps voice quality with obvious artifacts.
For example, I can play linear audio on my iPod that is an exact duplicate of the CD it was ripped from; on the same device I can also play music that is transparently or even aggressively compressed, and also lectures that are of such quality barely adequate for the understanding of speech. The quality reduction can be scaled to the need, and is invariably in reaction to a lack of data bandwidth or a desire to minimize storage space requirements.
The current digital audio broadcasting model offers scaling, too, allowing for more channels with a commensurate inverse level in quality for each of them. The problem, as I see it, is that at best the quality does not meet even that of 128 kbps AAC (never mind the linear format) that my little iPod offers!
From a scaled-quality standpoint, the scale starts pretty darn low, and only goes to worse. Added to that, with the limited amount of bandwidth available now on each broadcast signal, there is considerable economic pressure towards the bottom: More streams, even at lower quality, means more potential income.
So here we are, in a situation where the broadcast system in which audio is the focus (radio), at best actually offers worse audio quality than the system where video is the focus (HDTV)! Adding insult to injury, HDTV, with its nearly 400 kbps audio stream, even allows for relatively high-quality 5.1 channel surround sound.
I am a huge proponent of opening TV Channels 5 and 6 to broadcast audio services. My concern about any new broadcast band is that, if we should follow the model of the present IBOC system, we will lock ourselves into a broadcast system that does not allow for, never mind encourage, a quest for high quality.
Opening a new portion of spectrum offers the possibility to rectify this situation, if there is only the will. Is there?
David Reaves
Recklinghausen, Germany
