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The RME Hammerfall DSP 9632 PC Sound Card
Skipping A Forced Upgrade March While Sounding Good

Francis Vale

Presidential candidate debates are about on par with HDMI—Big promises, window fogging hyperbole, and much confusion with little actual satisfaction. HDMI promises ease of use by requiring just one cable to send both audio and video between components, like your HDTV and surround processor.

HDMI is a two-part spec. First, the good part--The HDMI spec incorporates DVI, a video specification created by the Digital Display Working Group (DDWG) to accommodate analog and digital monitors with a single connector. DVI is pretty much everywhere and on everything, including surround sound receivers and processors, DVD players, computers, etc.

There are three different DVI configurations: DVI-A for analog signals, DVI-D for digital signals, and DVI-I (integrated) for both analog and digital signals.

Now comes the bad news. The HDMI spec also includes HDCP, sometimes known as High Bandwidth Digital Content Protection. This is an Intel-developed specification to protect digital content transmitted and received by DVI-compliant displays. If you are using DVI-connected gear, but are playing HDCP encoded video content, sorry Bunky, no picture.

As for HDMI audio-only, oye! Many surround processors and receivers do not support audio-only HDMI, even when video switching is available. In the opinion of some high quality gear makers, like Arcam, HDMI audio-only suffers in performance. Confusion about this HDMI audio-only issue abounds.

For example, one forum post I found, supposedly from HDMI.org, stated that the HDMI signal always requires a video signal (it requires the video clock signal) in order to send audio (which sits in the blanking period of the video signal).

However, even a blank/dummy pattern (such as all black) video signal would work, so the audio does not have to be linked with a specific HD video signal. Another forum posting noted that the HDMI interface automatically configures the audio output for a format supported by the television. But, because not all TVs support, say, a Dolby Digital input, the HDMI interface may automatically select a 2-channel stereo audio configuration instead of Dolby Digital.

Thus, this situation must be manually overridden in the processor or receiver (if it can be done at all). Confused?  You should be! And this still doesn’t free you from the clutches of the audio protection mob.

With the likes of the RIAA threatening to sue granny for sharing her Lawrence Welk mp3’s, expect no shameless limits in “added-value” copy protection schemes from content providers. Hey, ASCAP has even sued the Girl Scouts of America to prevent little Mary and friends from singing copyrighted songs around the campfire.

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