Comcast 6412 DVR Review - AVS Forum
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post #1 of 3 Old 02-07-2005, 07:46 PM - Thread Starter
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I live in the San Francisco bay area, and just got the new Comcast 6412 DVR last week. As others have posted, there are many issues that I will not go into right now. The main one I want to focus on now has been pointed out in other reviews.

The picture quality is significantly worse with the 6412 in the signal path. The picture has allot of artificial noise. Random noise appears everywhere, but mostly around graphics. Scrolling text is a blur. Static and moving graphics are surrounded by a halo of noise. The worst channel is CNBC, which I watch quite a bit.

Here is the situation. I have a wonderful Sony XBR 32 inch TV circa around 2000. Great TV. This is an analog TV, but it does have component in. The 6412 only has component out. So the cable goes into the 6412, and then the component out of the 6412 goes into the component in of the Sony Tv.

After the bad picture, I installed cable directly to the TV, and at the same time through the 6412 so I could A/B compare, and the 6412 is the problem. I removed the other lines in the house and fed the signal directly from the pole into the 6412 and things improved, but were still worse than the signal using the TV tuner.

In my opinion, the problem is A/D and then D/A conversion. Comcast broadcasts analog signals for channels below 100. These get converted to digital in the 6412 and fed to the TV. The TV then converts these back to analog. The dual conversion is introducing the noise. The more analog noise in the line, the worse the final picture.

One reason I know this is the case is that the channels above 100 look great. I can watch the bloomberg channel which has the same kind of scrolling stock ticker and is all digital and it has none of these problems.

So the main issue here is the fact that I do not have a digital TV. Also, I primarily watch the analog channels below 100. I wish that comcast would offer digital cable that was ALL digital. But that will never happen. So for now I will have to live with poor performance until I buy a new Plasma TV sometime this spring. To those looking into the 6412, I would only recommend them if you like comcast channels above 100, and own a digital TV set.
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post #2 of 3 Old 02-08-2005, 05:15 PM
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Well that's a bummer. I was just about to go and get one as my ReplayTV doesnt' seem to work with Comcast's new lineup in Walnut Creek. Is there a way to increase the quality of the recording? The digital cable channels probably get the digital stream recorded directly but with tivo and replay you can select teh quality of compression.

Dyslexics are teople poo.
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post #3 of 3 Old 02-08-2005, 05:34 PM
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Quote:
Originally posted by 32XBR
I live in the San Francisco bay area, and just got the new Comcast 6412 DVR last week. As others have posted, there are many issues that I will not go into right now. The main one I want to focus on now has been pointed out in other reviews.

The picture quality is significantly worse with the 6412 in the signal path. The picture has allot of artificial noise. Random noise appears everywhere, but mostly around graphics. Scrolling text is a blur. Static and moving graphics are surrounded by a halo of noise. The worst channel is CNBC, which I watch quite a bit.

Here is the situation. I have a wonderful Sony XBR 32 inch TV circa around 2000. Great TV. This is an analog TV, but it does have component in. The 6412 only has component out. So the cable goes into the 6412, and then the component out of the 6412 goes into the component in of the Sony Tv.

After the bad picture, I installed cable directly to the TV, and at the same time through the 6412 so I could A/B compare, and the 6412 is the problem. I removed the other lines in the house and fed the signal directly from the pole into the 6412 and things improved, but were still worse than the signal using the TV tuner.

In my opinion, the problem is A/D and then D/A conversion. Comcast broadcasts analog signals for channels below 100. These get converted to digital in the 6412 and fed to the TV. The TV then converts these back to analog. The dual conversion is introducing the noise. The more analog noise in the line, the worse the final picture.

One reason I know this is the case is that the channels above 100 look great. I can watch the bloomberg channel which has the same kind of scrolling stock ticker and is all digital and it has none of these problems.

So the main issue here is the fact that I do not have a digital TV. Also, I primarily watch the analog channels below 100. I wish that comcast would offer digital cable that was ALL digital. But that will never happen. So for now I will have to live with poor performance until I buy a new Plasma TV sometime this spring. To those looking into the 6412, I would only recommend them if you like comcast channels above 100, and own a digital TV set.
Comcast has begun testing of simulcasting Digital on Analog Ch 2 - 100 in some areas, All Comcast areas will have full Digital cable before years end.... The Digital Cable box when turned to a analog ch. that is also broadcasting a Digital signal will switch and use the digital signal.

Check for more info in other threads on the AVS board....

---------------------------
Comcast of Lebanon PA.
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