Specifications

In my review of Blade II, I mentioned one of DVD's dirty little secrets: The X-Curve. Allow me to quote
myself, “For reasons too involved to describe in detail here (but associated with theater electronics and
the acoustics of a large room, as opposed to the acoustics of the typical small space found in a home
theater), film soundtracks are pre-emphasized. Frequencies above 2 KHz are rolled up at 3 dB per
octave (or better put, 1 dB per third-octave as measured with pink noise and a third-octave analyzer).
When the soundtrack is played back at home, to restore a ‘flat response' and remove the unnatural
brightness, the high frequencies are rolled off at -3 dB per octave from 2 KHz upward. For those of you
who own THX certified decoders or digital receivers, that's what THX re-equalization does. DVD's are
usually shipped with the pre-emphasis intact, requiring de-emphasis to restore tonal balance, so
without equipment capable of THX re-equalization, you may be at a disadvantage. ...there is one DVD
audio production house that removes the pre-emphasis as the audio is transferred to the disc: Mi Casa
Multimedia. They may be out there, but I'm unaware of other audio subcontractors that re-equalize the
audio prior to compression and authoring.” Learning in advance which DVDs have the X-Curve
removed is a challenge. Recently, that information has been included on some New Line DVDs' audio
set up screens. A helpful list of de-emphasized titles may be found at this Mi Casa Multimedia link.
When you listen to film audio at home in which the pre-emphasis is intact on the DVD and without X-
Curve de-emphasis (THX re-equalization) applied by your decoder, the sound will be too hot - too
much high frequency content. If you listen to a Mi Casa de-emphasized DVD with THX re-equalization
enabled, the sound will be too dull - too little high frequency content. The decoder mode must be
matched to the way the DVD's audio was produced: pre-emphasis removed, apply the flat mode; pre-
emphasis intact, apply the THX re-equalization mode. To ensure that I'd have that level of control, I
was predisposed to purchase a THX-certified decoder, the decoders that offer THX re-equalization. I've
always been rather partial to B&K Components. The company makes a fine product at an outstanding
price/performance ratio and supports its customer base with updates should they become necessary. I
chose the B&K Reference 30 THX Ultra preamp/decoder.
As for the other electronics, I didn't have to purchase anything else; on hand were a beefy power
amplifier from a German company for which I had provided engineering consulting services a number
of years ago, and a parametric equalizer prototype I had designed. For the loudspeaker, I had been
using an M&K S-100B for my EX center surround ever since I put the Pseudo-EX configuration in
place; it was chosen for its timbre-match to the other M&K loudspeakers in my system. It's rather
important that the audible characteristics of all of a system's speakers be very, very similar. Otherwise,
as a sound travels around the room (like during a 360 degree pan), the timbre will change; if the
sound's character varies depending on its location, it will draw attention to itself and possibly distract
the viewer to the point of collapsing a willing suspension of disbelief. And differences in frequency
response may also destroy accurate spatial imaging. So the S-100B remains.
Parting Thoughts
Improving the video chain was a little painful, but the results are wonderful. My presentation is closer
to film than I was able to achieve before. I'm looking forward to resolving my remaining RGB video
switch issue; I'm sure that will happen within a month or so. I'll report back with an addendum when I
finally have the total solution in place. Less recent was the audio upgrade; it's actually about two years
old. That upgrade was painless to implement and proved to be very satisfying, providing a noticeable
improvement in sonic accuracy.
I know there's a lot to consider here. Buying home theater equipment should be much easier (and
testing publications should be a lot more informative). I'm looking forward to the day when capable
audio and video equipment become pure plug-and-play. Until then, you almost have to hold an
engineering degree to get it done right. Once again, I hope you find some of the lessons I learned
while going through my upgrade helpful. The best of luck with yours.
Postscript
During the delay between my submission of this sixth installment of "Mr. Blandings Build His Dream
Theater" and its publication, Extron completed its investigation of my CVC200 transcoder's Macrovision
problem and devised a solution. My transcoder was returned to me, and it no longer pumps the video
gain for Macrovision protected DVDs; once again, it produces splendid images. At a higher price, the
Extron's output is free of sync pulses and offsets, and maintains color temperature with much greater
accuracy than the Key Digital. It was only necessary to boost my projector's green drives by about 4%
to achieve proper color temperature with the CVC200 (nothing's perfect). It's my understanding that
the changes made to my Extron transcoder have been passed along to manufacturing and all future
production units will be insensitive to Macrovision. And now I'll also be watching with great interest to
see if Key Digital corrects the problems I uncovered during my upgrade adventure as they introduce
future products.
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DVDFILE.COM: Mr. Blandings Builds his Dream Theater
4/7/2003
http://www.dvdfile.com/news/special_report/tech/mrblandings/upgrades.html