Question yamaha RX-V667 PROLOGIC 'll problem

Discussion in 'AV Receivers & Amplifiers' started by tooter, Aug 6, 2018.

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  1. tooter

    tooter
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    Hi I've just purchased a yamaha rx-v677 and I'm having a few problems. I will start with my setup. I have a 5.1 surround with active sub connected to my tv with optical. when my tv is playing from freeview the amp changes from Dolby digital to pro logic 'll constantly the same happens when I play a movie from the built in plex player if it's a Dolby 5.1 source or a acc source but if the source is dts the display shows dts. I can't figure out why it changes on Dolby but not on dts. all I put would be greatly revived thanks.
     
  2. dante01

    dante01
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    DTS and Dolby Digital are audio formats that can consist of 5 discreete channels of audio plus an LFE channel (5,1). THis isn't to say that all audio encoded as DTS or Dolby Digital will consists of this many channels of audio though. Pro Logic is an upmixing mode that creates pseudo channels in order to create pseudo surround from non surround sources or sources that are missing the full complement of discrete surround channels. If you've engaged the Pro Logic II Surround DEcoder mode then the receiver will apply this processing to any incoming audio that doesn't comprise of 5.1 or more channels of discrete audio. If for example the source was a 2 channel AAC file then the receiver would apply Pro LOgic to it to create pseudo 5.1, but if the source was encoded with Dolby Digital or DTS 5.1 then the Pro LOgic processing would be bypassed because it would not be required because the sources are already 5.1 in nature.

    You can disengage the Pro Logic processing mode by pressing the STRAUGHT mode button on the remote Pressing it again will reinstate the mode. You can change the Pro LOgic mode to another mode by pressing the SUR DECODER button on the remote. Use this button to cycle through the varios modes available to you.
     
  3. tooter

    tooter
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    Hi thanks for the reply so let me get this right if i push the straight button it still says dolby digital but only 3 speakers light up on the display the is because it is receiving a dolby digital signal in stereo and if I engage dolby-pl ll it still is receiving the dolby digital signal in stereo and changing it to pl-ll is that why it constantly swaps between dolby digital and dolby-pl ll.?
     
  4. dante01

    dante01
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    If you press STRAIGHT then you'll get whatever format the source is outputting without the eceiver applying any upmixing. It the source is stereo then you'd only get audio via the front 2 speakers, but if it is doscrete 5.1 then you'd get audio via all your speakers. Pro LOgic on the otherhand would upmix stereo sources and engage all your speakers, but would be bypassed by formats consisting of 5.1 or more channels of siscrete audio.
     
  5. tooter

    tooter
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    Hi thanks I understand that but my amp constantly swaps from pro logic 'll to Dolby digital over and over and don't understand why. (if playing from tv).
     
  6. dante01

    dante01
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    Not everything will include a Dolby Digital 5.1 soundtrack. The ad breaks for example will always be 2 channel even if the channel uses Dolby Digital for its audio format. Pro Logic would therefore kick in during the ad breaks or if the programme you are watching is only encoded with 2 channel audio. Dolby Digital doesn't have to consist of 5.1 channels and can also be 2 channel stereo in nature.
     
  7. tooter

    tooter
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    ok thanks but my amp seems to swap over every 10 seconds or so.
     

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