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LPCM 1.0 mono on Criterion Blu-rays

Discussion in 'Beginners, General Questions' started by kevin_y, Nov 14, 2012.

  1. kevin_y

    kevin_y Well-Known Member

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    Is it true that an HDMI cable is not able to carry LPCM 1.0 audio, only 2.0 to 7.1 LPCM audio?
    When a Blu-ray has LPCM 1.0 mono audio, like many Criterion Blu-rays, I notice that my player automatically converts it to 2.0 mono, which, of course, comes out of my left and right speakers, instead of the center speaker that it is meant to be heard from.
    Just curious what some of you would do in this situation. Would you (a) listen to it from LR speakers anyway, or (b) find a way to output it to the center. I don't see how (b) could be done without having the receiver remix the signal, which would yield a less than genuine sound, especially if the original LPCM 1.0 track is lossless. In my case, my receiver (Onkyo 605) wouldn't even let me remix the signal.
    Anyone can advise what to do in this situation?
     
  2. gene c

    gene c Well-Known Member

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    I'm just guessing here but I don't think it's an hdmi thing, I think it has to with a player or receiver not being able to turn off the front left and right speaker outputs, or render them silent.. I think the left and right front speakers must be used with all signals.
    The only way around this would be to turn off the surround speakers and lower the volume (or un-plug) the fronts and just have the center speaker outputting sound. You would need some kind of "all channel mono" surround mode in the player or receiver for that to work. And it would have to duplicate the mono signal to the center and surrounds and matrix it in anyway. But again, I'm just guessing here.
     
  3. schan1269

    schan1269 HTF Expert
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    Direct mode on all of my Onkyo/Integra play mono 1.0 only out the center speaker.
     
  4. kevin_y

    kevin_y Well-Known Member

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    Are you sure you were playing LPCM 1.0, not bitstream 1.0 (e.g. DTS-MA HD 1.0 or Dolby Digital 1.0)? Because I get center speaker output too when I play bitstream 1.0 audio. But not LPCM 1.0. Poster# 10227 on this page also says HDMI does not support single channel audio.
     
  5. schan1269

    schan1269 HTF Expert
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    It isn't an "HDMI problem"...
    It is a problem in AVR themselves not understanding a 1.0 LPCM.
    Typically, if you set your BD player as bitstream...your AVR "should" accept the signal.
    It depends if the AVR can digest the 1.0 as sent from the BD player.
    I have 3 BD players. 2 Panny BD35 and 1 Sony 350.
    The Sony won't pass understandable 1.0 no matter which format the disc is. I get mono 2.0.
    The Panny BD35 send along a 1.0 no matter if lossy or DTS-HD/DTHD.
    It is "player and AVR compatibility"...not the HDMI itself.
    Also, the same thing happens over toslink and digital coax. It would be interesting to check a multi-channel connection. (which I can do this next time I watch a 1.0 LPCM DVD)
    I would assume, that if the player can create a 1.0 output...it would run across an analog...then it would be irrelevant what the AVR would do to it.
     
  6. Mark-P

    Mark-P Well-Known Member

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    I don't know why your system wouldn't be able to process LPCM 1.0, however anything delivered to your receiver as 2.0 mono can easily be steered into the center channel by engaging Pro-Logic mode, and no, there's no loss in sound-quality by doing this.
     
  7. kevin_y

    kevin_y Well-Known Member

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    Are you guys sure it's not an HDMI issue? I checked out the manuals on some of the receivers. The "About HDMI" section (Page 34) of the Onkyo 605 manual says the supported audio formats are "2-channel LPCM, multi-channel LPCM", etc. Also in the "About HDMI" section (Page 106) of the Onkyo 818 manual, it says, "With HDMI, a single cable can carry control signals, digital video, and up to eight channels of digital audio (2-channel PCM, multichannel digital audio, and multichannel PCM)." Neither says it can carry 1-channel LPCM.
     
  8. schan1269

    schan1269 HTF Expert
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    Well, like I alluded to earlier...
    Try a toslink. See if a toslink has the same hangup. When I've watched 1.0 sountracks(LPCM and lossless), my Panny BD35 have no problems sending 1.0 that is understood by the AVR.
    So, connect a toslink and see if it still won't do 1.0.
     
  9. kevin_y

    kevin_y Well-Known Member

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    I currently don't have a Toslink cable to try. But when I use a coax cable (S/PDIF), the audio still comes out of LR speakers, but I'm able to use Pro Logic to make it come out from the center. As I mentioned, the Onkyo 605 would not let me use Pro Logic on LPCM via HDMI.
    The manual of the 605 also mentions that Pro Logic is allowed for PCM (as carried by the coax cable), but not for LPCM via HDMI . See this page. The checkmarks for Pro Logic (PLII) are under PCM but not multichannel PCM.
    S/PDIF also supports 2-channel PCM only, no? That brings back my original question: does HDMI support 2-channel PCM, but not 1-channel?
    P.S. (off topic) The manual page I mentioned above shows another quirk of the Onkyo 605. Footnote #1 says "For PCM 176.4/192 kHz signals input through HDMI IN, only ... Stereo listening modes can be selected. " That means if you have a 5.1 PCM 192 kHz signal, the 605 will output it as stereo only. Not too many Blu-rays have 192 kHz audio, of course, but sadly I have one: the Blu-ray for the 1988 anime Akira. It has a 5.1 PCM 24-bit/192 kHz audio track that I can't hear in 5.1 because of this.
     
  10. kevin_y

    kevin_y Well-Known Member

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    I asked Criterion if they would use DTS-HD MA mono instead of LPCM mono and below is their reply. Basically, they use LPCM mono for legacy support. But then again, they have discs where DTS-HD MA is the ONLY track, which doesn't help people with legacy equipments.
    - - - - - Original Message - - - - -
    From: Jon Mulvaney
    Sent: Monday, November 19, 2012 4:41 PM
    Subject: Re: LPCM 1.0 mono versus DTS-MA HD 1.0 mono
    Hello Kevin,
    Thank you for your email.
    We're aware of this issue but choose to encode our mono feature audio
    on Blu-rays as LPCM 1.0 to provide lossless audio to the most
    receivers. Though the number is dwindling, many people still use high
    quality legacy (older) receivers without the capability of decoding
    the newer lossless codecs (i.e. DTS-HD MA). Almost all older receivers
    are, however, capable of decoding LPCM audio so encoding our features
    as such allows them to listen to the lossless audio stream. One
    possible work-around for your situation (depending on your receiver)
    is to set your player up to output LPCM audio over a TOSLINK cable and
    rout that audio out the center channel of your surround system.
    I hope this helps! Please let me know if you have any further
    questions or concerns, and thank you for supporting Criterion!
    Jon Mulvaney
    On Tue, Nov 13, 2012 at 1:11 PM, - wrote:
    > Hi Jon,
    >
    > I notice that on nearly all Criterion Blu-rays, the mono track is always presented as LPCM 1.0. Many people, like me, connect their Blu-ray players with HDMI cables. And you may already know that HDMI cables are not capable of carrying 1-channel audio. They can only carry 2- to 8-channel audio per industry standard. If a 1-channel audio is used on an HDMI cable, it will be converted to 2-channel mono by the player (if it is able to). Hence, when we play LPCM 1.0 on our Blu-ray players, we do not hear the sound from the center speaker; we hear it from the left and right speakers, which may produce subtle differences in our listening experience. So my question to you is: would Criterion consider encoding 1.0 mono via a *bitstream* (such as DTS-HD MA, like some other studios do) instead of LPCM?
    >
    > Thanks for any assistance you can offer,
     
  11. Mark-P

    Mark-P Well-Known Member

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    Dude, this really isn't an issue. Engage Dolby Pro-logic mode and your problem is solved: sound will only come out of the center speaker.
     
  12. kevin_y

    kevin_y Well-Known Member

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    As I said in my earlier posts which you apparently didn't read in full, my receiver (and presumably others too) doesn't always let you use Pro Logic, so it IS an issue.
     
  13. Mark-P

    Mark-P Well-Known Member

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    Well that's a shame that Onkyo doesn't allow you to select various listening modes for LPCM through HDMI. In that case your only solution is to hook up the old analog L/R inputs because I know you'll be able to engage Pro-logic through those.
    Truly I'd blame Onkyo for this problem, not Criterion.
     
  14. schan1269

    schan1269 HTF Expert
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    I'll have to find(download more likely) the manual for the Integra DTR 5.8(same thing as the 605) that is now collecting dust, cause I replaced it with a 7.8...
    Anyway, both the 5.8 and the 7.8 don't have a problem decoding 1.0 LPCM. But, both of those AVR were connected to a Panny BD35.
    So, maybe Onkyo and Integra aren't the "clones" everybody thinks they are...(sarcasm)
    By the way, I listen to Rosemary's Baby via the center speaker in "direct" mode with the 7.8 and NR1008...no problems. But both of those AVR are blessed with the BD35...(I have two BD35).
     

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