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Sound Advice: Technology Q&A
Nov 09, 2009 (McClatchy-Tribune News Service - McClatchy-Tribune News Service via COMTEX) --
Q. I am experiencing a frustrating situation with my audio/video system, described by my cable provider as a "handshake" issue. I have an Onkyo TX-SR606 A/V receiver, a Sony Blu-ray player, and a Sony Bravia HDTV. While watching HDTV from my cable box I occasionally lose the audio/video signal for 4-5 seconds. There is no issue on non-HD signals and some stations seem to be more affected than others. Blu-ray is not affected.
I use HDMI cables to connect my cable box and Blu-ray player to the Onkyo receiver, and another HDMI cable to connect the receiver to the TV. The cable provider downplays the importance of the HDMI connection and at their suggestion I have connected a second set of cables (component video- red, blue, green, plus an audio cable.) I don't believe the component video picture quality looks as good as HDMI. Do you have any suggestions to eliminate the signal loss? When I buy components in the future how can I avoid these problems?
_R., Moon, Pa.
A. What you are experiencing is problems with the "HDMI handshake" that occurs when using HDMI connections. HDMI connections incorporate HDCP, short for "High-bandwidth Digital Content Protection." HDCP is an anti-piracy measure implemented by software and hardware manufacturers. Unfortunately HDCP often affects innocent consumers by causing viewing disruption and operational headaches.
Each of your components (receiver, cable box, Blu-ray player, and HDTV) is HDCP-compliant. When a signal is sent over HDMI the components communicate with each other to ensure all the devices are legal and compatible before allowing the audio/video signal to pass through. This communication protocol is referred to as the "HDMI handshake." If a successful handshake is not established you will (usually) get a warning message saying you need HDCP compliant equipment and the picture and sound will be disrupted. Because the red/blue/green component connections are not digital they are unaffected but as you have seen, HDMI offers superior picture quality.
Using the proper turn-on sequence can help establish a solid HDMI handshake. First turn on the TV, let it run for a few seconds, then turn on the receiver, give it a few seconds to boot up, then turn on the cable box and Blu-ray player. If the signal is cutting out while viewing, switching back and forth between TV or receiver inputs will often re-establish the handshake.
Given the problem is only with the cable box I suspect your provider is doing a poorer job with their signals and equipment, especially if they told you to go component connection instead. I would ask them for an updated cable box.
I know of no components that are 100 percent free of handshake issues. It is unpredictable and components seem to have varying degrees of handshake issues when used together. For example, in my home one satellite box has occasional issues with my Anthem AVM 50 processor and a Sony projector, but an identical satellite box in another room works flawlessly with an Onkyo TX-SR606 receiver and a Samsung plasma TV. To give you an idea of how unpredictable it can be, in the latter system when I turn off the TV it stops the Samsung Blu-ray player because the HDCP signal path has been changed. However, turning off the TV does not stop the Panasonic Blu-ray connected to the same receiver!
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Read past columns and product reviews by Don Lindich at www.soundadviceblog.com, and contact him using the "submit question" link on that site.
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