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Weekly AUDIO NEWS for April 9, 2003

The Hi-Res Filter Debate - At the recent NYC launch party for Pink Floyd’s Dark Side of the Moon SACD, two of those involved in the production made some anti-DVD-Audio remarks that caused a furor in the opposing camp. Producer James Guthrie said in his speech that there were two reasons they decided on SACD for reissuance of the classic album: One was the confusion surrounding DVD-A. He said “...the lack of understanding is very real.” The other was an issue he had with MLP (Meridian Lossless Packing) encoding, described as “Quick-fix high-frequency filters on the final product also defeats the concept of a high-resolution format.” David Kawakami, of the Sony SACD Project, further described this as a practice to reduce audio bandwidth to gain program length. However, both admitted they had not worked with DVD-Audio mastering themselves.

The reaction from those who have been working in DVD-Audio authoring was unanimous in stating that Guthrie and Kawakami were misinformed. John Kellogg of Dolby Labs (who license MLP to the industry) said that it does not require filtering or word length reduction and neither are recommended. “If a file is corrupted...then the solution is to go back and create a clean file,” he explained. Others stated that in their experience no one had to do such filtering on any of the 500 or so DVD-As that have so far been released. Craig Anderson of Warner Bros. said MLP has so far been, as its name implies, lossless. He suggested the SACD camp was confusing “recommended low-pass filtering” (of DVD-A) with “required low-pass filtering” of DSD (the 50K filter in all SACD playback devices which is required to remove the undesirable high-frequency noise brought about by DSD’s aggressive noise-shaping filters). The last word came from the inventor of MLP, Bob Stuart of Meridian. He said they do not advocate the use of filtering in routine DVD-A production or playback and they are not aware of it being used as part of the authoring process by anyone. He said that in fact brick-wall filters are completely unnecessary in audio PCM systems running at sample rates of 88K and above.

Classical Listening Decline Due to Home Theater? - Ken Pohlman expounds an interesting and controversial theory in this month’s SOUND & VISION. It’s that movie soundtracks and pop music sound fine on the typical home theater surround system - even entry-level versions. However classical music sounds bad, and therefore people don’t want to listen to it as often. He points out the LFE and center channels are really not needed for music (we agree), and that having five full-range speakers all the way around is beyond the budget (or space) of most folks. Therefore the dependence on small bass-shy satellite speakers and a single subwoofer, which can do a fine job on soundtracks and pop - similar to what you get in a real movie theater. However, classical music (aside from pipe organ) doesn’t have much extreme bass content, the satellites have to do all the work, and they don’t handle well that normal bottom end of the spectrum where they begin to cross over to the subwoofer. He points out that to meet a popular price for a complete six-piece home theater speaker system (such as $1000) you just cannot get the same smooth and rich frequency response you get from a pair of traditional stereo speakers at that price level. Therefore he predicts that as home theater continues to take over, classical music listening in the home will decline further. Let's hope he's wrong.

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