NAD T 747 A/V Receiver Video Test Bench

Video Test Bench

The Picture Setup adjustments (Brightness, Contrast, etc.) did not appear to permit different settings for each source input. The NAD passed most of the Digital deinterlacing tests easily (HDMI in to HDMI out), but only with the Film Mode Detect control on (in Picture Setup—its default position is off). I recommend that for all sources.

The NAD’s Picture Adjust menu gives you two options: Normal, which doesn’t offer any video adjustments, and Custom, which does. In the Normal mode the receiver responds up to a white level of 234, but no higher. In the Custom mode, it clips just below 224, even if you don’t change the adjustments from their default positions. To obtain the NAD’s best white clipping result in the Custom mode, you have to turn the Contrast setting in the Picture Adjust menu down to 30. The receiver will still clip above white by design, but at that setting it does respond up to digital 234—very close to the digital video peak white level of 235. To earn a passing grade on our clipping tests, however, a component must respond above white (235) and below black (16) to provide adequate headroom and toeroom. Below black was compromised as well, clipping at 17 to 18, with nothing below that.

Both of the Analog Resolution tests failed on the highest-frequency HD bursts. A 1:1 pixel map pattern was not properly reproduced either. Video clipping failed here as well with above white compromised. The brightness level was much higher with the analog component video input/HDMI output than the digital HDMI input/HDMI output.

I wouldn’t use the NAD’s cross-conversion feature unless the source is totally non-critical. The clipping over HDMI may not concern all viewers. But if, like us, you want your video chain to have adequate headroom to accommodate source material that may exceed the normal video limit, and want an optimal setup for display adjustment and calibration you should avoid the NAD’s video switching. This means that the only way to hear high-resolution formats (short of an external splitter or a Blu-ray player with multiple, simultaneously functioning HDMI outputs) will be via a multichannel analog audio connection, with the Blu-ray player doing the audio decoding.—TJN

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