D-to-A, A-to-D, and sound quality

November 18, 2008

To Wes Marshall,

I just read your review of the Oppo DV-983H, and I had a question for you. If you use the HDMI output (instead of analog outputs) to your receiver, aren't you bypassing all of the D/A conversion inside the player and assigning that to your Integra receiver? (I have the Onkyo 805 which, I believe, has similar DACs to yours.) If so, why would a CD or SACD sound any different from the Oppo than if you used the PS3’s HDMI output, as your receiver would still be doing the D/A conversion, correct? I'm sure there’s a reason for this. I just haven't been happy with the audio performance from my PS3 and was looking for a relatively inexpensive high-quality universal transport, which are in short supply.

I have also heard good things overall about the Toshiba XA2 as a transport, but it is not universal. Any recommendations you can provide would be greatly appreciated.

Cory

Signals go through the following stages getting from a studio to you: Analog music, digital mixing, digital mastering, digital media, and then analog playback. This is sometimes abbreviated as D/A and A/D.

The longer you can keep the digital signal in the digital realm, the better. If you use the analog outputs of your DVD player, it now goes D/A to A/D to D/A. If you use either the optical or S/PDIF digital outputs, you maintain the single trip from analog to digital and back -- unless you are listening to an older DVD-A or SACD. The music folks tried to prevent us listeners from the single-trip conversion and force a double swing by requiring the output go through a 5.1-channel set of analog outputs. With newer equipment, and the Integra and Oppo are some of the first on the market to handle this, if you use the HDMI output, the music will go through only one trip on the D/A merry-go-round.

Transports do sound different.

If I were you, I’d get the most expensive Oppo that suited my budget. I think that your 805 should be able to accept the SACD and DVD-A 5.1 signals via HDMI, but you should ask to be sure....Wes Marshall

“The Torture Cycle” article -- Cartoon on LSD

November 4, 2008

To Wes Marshall,

I just read your article. Boy, have I been there.

Did you ever find out what the cause of the cartoon look was? I have a scaler that does the same thing with HDMI intermittently. It's very hard to track down.

Bill

The person I trust regarding such issues says that something is clamping down on the video signal, knocking the effective bit rate down into low single digits. The only way to determine where the bottleneck is to replace things one at a time, starting at the source and ending with the display, as in DVD->HDMI Cable->scaler->display->projector. You may have more of fewer steps, but the idea is to start on the opposite side of the chain from the screen (in other words, at the source) then work your way through any part of the system that touches the video signal.

In my most recent case, the projector and processor weren’t getting a good handshake. Each piece of equipment worked fine with on its own, but put the two together and problems reigned....Wes Marshall

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