LD with Denon 3801/3802

Discussion in 'Archived Threads 2001-2004' started by Mike Thompson, Aug 5, 2001.

  1. Mike Thompson

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    I am thinking of upgrading my HT system. Since none of the newer receivers seem to have RF inputs (except 5800), what is the best sort of RF decoder to use? Some of them output 5 channel discrete, while others convert the RF to digital. And how does the bass management work with the discrete units? Not sure which way to go here. Anyone with actual experience in this area? Thanks.
    Mike
     
  2. Stacy Huff

    Stacy Huff Second Unit

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    Mike,
    The Dolby Digital soundtrack on an LD is carried on one of the analog channels, and is output through the AC3 RF jack. I'm not exactly sure of the particulars, but I believe a simplistic way to think of it is that the Dolbly Digital signal is carried on an RF signal. You need an AC3 RF demodulator to strip the digital signal out and send it to your receiver. The signal that reaches the receiver is just a digital signal, and it will be carrying the full 5.1 channels.
    I don't think that any company is still making demodulators. They are hard to come by. You can check Audiogon, and they have a link to somebody selling the B&K demod.
     
  3. Michael Reuben

    Michael Reuben Studio Mogul

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    quote: Since none of the newer receivers seem to have RF inputs (except 5800), what is the best sort of RF decoder to use? Some of them output 5 channel discrete[/quote] Sorry, no such animal. An RF demodulator (not "decoder") converts the analog RF signal to digital -- and that's all. No DD decoding, no bass management. If the demodulator happens to be incorporated into a unit that also contains a DD decoder, that unit will output 5-channel discrete and may have bass management features. But then you're talking about a receiver or a pre/pro.
    As already noted, the issue is not which demodulator to get, but getting one at all. If you can find one at the right price, just buy it.
    M.
    [Edited last by Michael Reuben on August 05, 2001 at 01:42 PM]
     
  4. Mike Thompson

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    Thanks......I think. Marantz calls their DP870 a DD Decoder, Yamaha calls their DDP-1 a processor, etc. None of these are pre-pros as there are no other inputs. Technics makes a model that is strictly a demodulator, I think. So semantics aside, I was hoping to find someone with some experience with either of these two different methods of obtaining Dolby Digital from LD RF, and give me some advice as to which works better. There are always units available on eBay for this. And right now there are some new Sony SDP-E800, units available cheap. Any experience with these?
    Mike
     
  5. Michael Reuben

    Michael Reuben Studio Mogul

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    quote: So semantics aside, I was hoping to find someone with some experience with either of these two different methods of obtaining Dolby Digital from LD RF, and give me some advice as to which works better.[/quote] After five years of playing DD LDs, I'd say I have a fair amount of experience. So please believe me when I tell you that there is one, and only one, method of obtaining DD from LD RF:
    1. Convert the RF to a DD bitstream (which happens in the demodulator).
    2. Decode the DD bitstream to analogue (which happens in the receiver or pre/pro).
    Receivers with a built-in demodulator perform both stages. Standalone demodulators, regardless of what the manufacturers choose to call them, perform only the first stage. And you wouldn't want it any different. If you have a DD receiver or pre/pro, you've already gone to the trouble of setting it up and calibrating it to your system (adjusting the relative volume levels, setting the bass management, etc.). So why, when you play a DD laserdisc, would you want to turn over the DD decoding to an entirely different device?
    There may have been one or two early units, when DD was new and LD was the only source, that combined RF and DD decoding and then passed the 5.1 analog signal to an amp or receiver. I think Pioneer made something like that as a transitional product, before DD became a standard feature on a/v receivers. I'd be surprised if you could find such a unit today -- and if you did, you'd want to bypass the DD decoding, which would almost certainly be inferior to what any contemporary receiver has to offer.
    The only demodulator I've ever used is a Lexicon LDD-1, which is no longer made and which no one would buy if it were (too expensive for a world in which LD is virtually a dinosaur). Leaving aside extra features such as automatic bypass or special calibration options, demodulators are all pretty much the same. If you're sure you want to go this route and you can get the Sony unit, don't hesitate. In a week or two, it may be gone.
    M.
    [Edited last by Michael Reuben on August 05, 2001 at 05:40 PM]
     
  6. Mike Thompson

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    Thanks Mike. Your comments about not disturbing the DD settings of the main receiver/processor with another 5.1 analog input are well taken. So I have to find a true demodulator. That's more difficult.
    Mike
     
  7. Michael Reuben

    Michael Reuben Studio Mogul

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    Just took a look at the specs on the Sony SDP-E800. I'd call it a pre/pro. It does DD decoding and DPL processing, includes bass management, and has inputs for several DD sources. You could connect it directly to a five- or six- channel amp for a complete DD system.
    It appears to have a single digital out; so it's possible that the unit could be used just for its built-in demodulator, with the resulting digital signal redirected to a different receiver. I suppose, if the price is right and you can verify that the digital out would work this way, this could be as good a solution as any for a demodulator.
    M.
     

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