Component bandwidth, Yamaha vs . Denon

Discussion in 'AV Receivers' started by Bob*W, Jul 9, 2004.

  1. Bob*W

    Bob*W Auditioning

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    Educate me further on component input bandwidth. I've read that HDTV requires 30 MHz (1080i). I've also seen recommendations that advise at least 50 MHz for HDTV. Is this overkill or a safety buffer to ensure no loss of video quality?

    I ask because the two receivers under consideration for purchase (Yamaha 2400, Denon 3805) differ by a substantial amount on the spec sheet. Yamaha quotes 60 MHz, Denon 100 MHz. Should this be concern? I plan on running component from cable HD box through the receiver and to the TV (Sammy DLP).

    If only the DVI port on the cable box was active this would be a non-issue!
     
  2. Alan Wise

    Alan Wise Stunt Coordinator

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    Bob,
    This is a topic that I am very surprised hasn't been more widely discussed.
    In early June I upgraded receivers from a Yamaha RX-V640 to a Denon AVR-3805. In my reviews to everyone I stated that even my wife commented on the increased clarity of the picture on our Sony KP-57WS510 HD-RPTV with the Denon. My only explanation is that the Denon has a 100mhz band width, and the Yamaha had 50 mhz. Like you, I too connect everything through my receiver (including my Comcast/Motorola 2005 Digital/HD Box)with one set of component cables going to the TV. I am using the same calbes, placed in the same locations as with the Yamaha receiver.
    I would like to hear someone of knowledge (Chu, John Garcia, etc...)comment on this.
    If it is known that a higher band width is more desirable, then the new Rotel AVR (the 1067?)which has 200 mhz would be wonderful.
    Any comments?

    Thanks, Al. Wise
     
  3. Bob McElfresh

    Bob McElfresh Producer

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    Here are some facts:

    Component Video - 4 Mhz max
    Progressive video (480p) - 13 Mhz Max
    HD Video (720/1080) - 35 Mhz

    Here is the trick: an engineer looks at the max frequency he plans to shove through a cable or electronics and then select the components with 3 or 4 times this amount of bandwidth.

    This is why Yamaha, Audio Authority, Canare/Belden all make recievers, switchers and cables with 90 - 100 Mhz bandwidth to carry HD video that tops out at 35.

    Here is the problem: When video signals suddenly change (like black->bright white) it creates problems along the signal chain. While the change does not really cause 2X or 4X the frequency signals - the problems are reduced or eliminated if the components were designed for 2-4 times the max frequency.

    (Kind of like car tires. 120 Mph speed-rated tires perform better even at low speed than 80 mph rated tires.)


    You want to go with the Dennon. Or you can buy a external video switch box from Audio Authority for about $200-$250 that can handle 4 different sources and will learn codes from your remotes so the audio & video stay in sync.

    This thread on Inexpensive HD Video Switching talks a lot about external switchers.

    Hope this helps.
     
  4. Bob*W

    Bob*W Auditioning

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    Bob,
    Thanks for your insightful reply. I had a feeling the Denon would be picked. There are no dealers in this area that carry the 3805 (one place is authorized, but they claim to have stopped carrying the receiver line due to quality control issues. They carry Yamaha, Rotel, and Integra).

    So, regardless of brand, as long as the receiver has at least 100 MHz bandwidth, I'm OK for the forseeable future. Correct?

    Or I connect the HD cable box directly to the TV and use the receiver for audio only.


    Bob
     
  5. Shane Martin

    Shane Martin Producer

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    I suspect Yamaha will change their tune next year. I know Pioneer Elite's new receivers have 100mhz switching on their upcoming stuff so that combined with Denon seems to indicate that the market is headed that way. I'm not 100% certain I'd notice a difference but I'd prefer to be safe than sorry.
     
  6. Bob McElfresh

    Bob McElfresh Producer

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    I thought last year all Yamaha recievers that claimed to be "HD Video Compatible" had a bandwidth of around 90 Mhz. Anything in the 90/100/110 Mhz bandwidth is fine for HD.

    Connecting straight to the TV with a true HD source is usually the best (less breaks, less things to come loose, fewer cables).

    You only want to go through the reciever if you have 2 or more component sources. The sad part is: most TV's and recievers only offer 2 input sources so it's easy to fill them up.

    The external HD Video switch box has saved many a member from scrapping a perfectly good reciever to get one with an extra component input. Let that be your fall-back if you prefer to get the Yamaha.
     
  7. Chu Gai

    Chu Gai Lead Actor

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    As Bob stated, the engineering rule of thumb is 3x the bandwidth of the signal you're passing in order to not have noticeable degradation. I honestly don't know how legit manufacturer's spec's are when they give a number. What it's supposed to mean if the receiver has a video bandwidth of say 100 MHz is that the signal is 3 dB down (half strength) at 100 MHz. In the absence of further information, I'd assume that it's a linear relationship with respect to the frequency, i.e. at 35 MHz the signal strength would be attenuated by...

    (35/100) * 3 db = 1.05 dB

    I suspect we'll be seeing more of the 100 MHz bandwidth or greater (Rotel I think is something like 150) at lower price points. If you need the greater bandwidth but don't feel like chucking your receiver, Bob had a thread that he started that dealt with aftermarket products. Maybe he can recall the link. It was a good one.
     
  8. Alan Wise

    Alan Wise Stunt Coordinator

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    Bob and Chu,thanks for the excellent in-depth explanation.
    This is enlightening.

    Al. Wise
     
  9. Chu Gai

    Chu Gai Lead Actor

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    Hey, I was born in Methuen, Mass. Bon Secours Hospital still there?
     
  10. Alan Wise

    Alan Wise Stunt Coordinator

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    Chu,
    The hospital you are refering to is now called "Holy Family Hospital". I live about a mile from there.
    It is truly a small world.

    Regards, Al. Wise
     
  11. Chu Gai

    Chu Gai Lead Actor

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    Certainly is Alan. I recall getting my tonsils out there in first grade.
     
  12. Bob*W

    Bob*W Auditioning

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    Many thanks for some fine responses. I am leaning toward the Yamaha 2400 despite the 60 MHz bandwidth because I like the other features of the receiver as well as the value. I'll certainly report any visual differences once I get everything set up.
     

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