[mythtv-users] AC3, Analog Cable and 5.1

Brian Wood beww at beww.org
Thu Mar 23 03:20:29 UTC 2006

On Mar 22, 2006, at 7:04 PM, Michael Heironimus wrote:

> That being said, very few TV programs make any real use of Dolby
> Surround. When I play a DVD I'm surprised if it doesn't have at  
> least 4
> channel audio, but I'm even more surprised when a TV show on cable has
> anything on the rear channel. Usually almost everything is through the
> center channel.

One of the first shows to use surround sound encoding was the old  
"Arsenio Hall" show. This caused a lot of problems because most  
stations transmitting stereo use a "monoguard" to detect and correct  
an out-of-phase condition, which will result in almost inaudible  
sound on a mono receiver. Since the encoding used phase modulation it  
drove the monoguard crazy, switching back and forth trying to correct  
what it detected as a "fault". Stations were given no warning of this  
at all and it was a real problem. Eventually everyone just switched  
off their monoguards for the program but it still created strange  
sounding stuff on a mono set.

Just thought you might be interested in some ancient history.

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