Strange audio issue

Discussion in 'Apple TV and Home Theater' started by Viper119, Sep 17, 2013.

  1. Viper119 macrumors newbie

    Sep 15, 2013

    First up, the setup, I've got:

    -Yamaha CRX-M170 amp/receiver (Doesn't have optical audio in).
    -2x Wharferdale speakers (2.1 sytem).
    -Xbox 360 S connected to TV via HDMI, and to Yamaha via Phono RCA cable (Through the TV).
    -Maxbook Pro (2010 era) connected to TV via HDMI for video, then to the Yahama via the headphone jack using a stereo to Phono RCA cable for audio.

    Note all audio is going out via the Yamaha 2.1 system.

    Playing iTunes and older videos on the Macbook Pro the audio quality is fine.

    However when playing newer 720/1080p movies with 5.1 or higher digital audio tracks, the audio quality is really bad, very distorted.

    If I play the same movie on the Xbox instead, I don't get the same audio issues, it's fine. (Reason for playing some movies on the MBP is Xbox doesn't play .mkv's).

    It seems like the issue is the 5.1 or higher to 2.1 conversion the Macbook Pro is doing. The Yamaha has a DSR-70 PRO digital decoder and it seems to work for conversion fine, Xbox has no issues.

    Any ideas on potential solutions for this? The googling I've done alludes to either a toslink optical converter out of the headphone jack, an external sound card or perhaps better drivers/codecs. Not sure what to go with?

    Many thanks in advance for any help!
  2. palmharbor macrumors 6502

    Jul 31, 2007

    Can U get an analogy audio output to feed your receiver, if you can I suggest you use it
  3. waw74 macrumors 68030

    May 27, 2008
    what program are you using to play the videos?
    where did you obtain the videos?

    how does it sound on the speakers in your mac?

    i'm assuming your mac does not support audio over HDMI, I think they added that feature in 2010, so you're right on the edge.

    you want to make sure the volume on the player on the computer is about in the middle of the range. then use the volume on your amp to control the volume going to your speakers.
  4. Viper119 thread starter macrumors newbie

    Sep 15, 2013
    Thanks for the reply guys.

    Using VLC Player to play the files.

    They are downloaded movies, 720/1080p quality in MKV or AVI format.

    The mac speakers have the same audio distortion/quality issue.

    I've tried it with the Mac doing audio out via the HDMI cable, then audio out from the TV to the receiver via a phono RCA cable. As well as via the Mac's headphone jack to the receiver with a stereo to phono RCA cable. Same issue both ways, so that rules out the HDMI I think.

    I'll try the volume settings and see if it changes it.

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