Converting stereo to surround and allocate sound to different channels

Discussion in 'Apple TV and Home Theater' started by Masioni, Jan 19, 2014.

  1. Masioni macrumors newbie

    Jan 19, 2014
    I've been searching for a few days, but can't find a solution for my problem. Hoping you guys can help!

    I have a logitech Z5500 surround system hooked up to my TV. However, I also would like to play the music from my MacBook over the speakers while I am sitting at my desk. The problem is, the desk is right-angled to the TV so instead of hearing left and right sound I hear only the left sound and the right sound is somewhere far behind me.

    A little sketch of the situation:


    +MB+ (-:


    L is left speakers, Ls is left surround speaker, etc. I am sitting at the smilie facing the MB and thus hearing the left channels.

    Is there any way (besides rewiring the channels every time I go from TV to MB) to convert the sound that my macbook is outputting to surround sound and allocating the left and right sound to Ls and L?

    Already tried soundflower, AU lab, MIDI control setup. Logitech Z5500 is connected via digital output.
  2. Irishman macrumors 68030

    Nov 2, 2006

    Just get a cheap set of computer speakers for your Macbook and call it a day.

    OR, plan B - get a bluetooth speaker or wi-fi speaker so that you can play it anywhere (BT within 30 feet and wi-fi within 100 feet).
  3. mchalebk macrumors 6502a

    Feb 4, 2008
    Have you tried some of the different settings on the your Z5500, like Stereo x2 or Dolby Pro Logic II Music? These should at least use the front and surround speakers and might be more satisfying than front only.
  4. Pyromonkey83 macrumors 6502

    May 24, 2009

    I used to use this program a while back to do a "speaker fill" type option from my headphone port back before I got my receiver (which does that automatically now). If I recall correctly, there was a way to select each individual speaker and set the output, but I could be wrong as it has been years since Ive used the program.

    Let me know if it works for you!
  5. Masioni thread starter macrumors newbie

    Jan 19, 2014
    @Mchalebk: Enabling the Dolby Pro Logic II Music only converts the stereo signal into some sort of emulated surround sound. As this is done by the Z5500 I sadly can't change the channels it outputs to.

    @Pyromonkey83: Thanks for the tip! Just downloaded the app and will be looking into it tomorrow. In the Netherlands it is almost bed time ;-)

    This part in the FAQ of JACK really gets my hopes up!
    Other Cool Things About JACK
    Because of JACK's level of integration, it's possible to provide all programs using JACK with facilities that traditional systems like ASIO or WDM force each application to develop for themselves. For example, there are JACK-using programs that will stream audio from any other JACK program (or programs) to an Icecast server for direct broadcast over the internet. Or consider a JACK program that encodes five channels of input as AC3 and forwards it to a S/PDIF port on your audio interface - instant surround sound compatibility for all JACK clients without redundant code in each one. Finally, consider JACK's transport control system that allows all JACK programs that have "transport" systems to run in sync with each other, even in the presence of programs that cannot locate to new transport positions immediately.
  6. mchalebk macrumors 6502a

    Feb 4, 2008
    Did you try the Stereo x2 setting?

    I use the 5 channel stereo setting on my receiver to listen to music, fills the room with sound. It sounds like this setting should be similar (except it only uses 4 channels). Don't know that it will help, but it's worth a shot.
  7. Masioni thread starter macrumors newbie

    Jan 19, 2014
    It is almost working! :D

    JackOSX intercepts the sound and can reroute this to different channels. However, it detects the same output channels as mac does. Luckily, some genius by the name of Jesse Chappell has made AC3Jack. This is some sort of plug in for JackOSX that converts stereo sound into AC3 5.1 and gives the option to push out the digital regardles of the OS recognition of a capable receiver. This way my Z5500 picks up the AC3 signal and switches to surround sound, thus giving the option to route each channel to each individual speaker in the 5.1 setup.

    One problem to solve left; it stutters (or lags, don't know the exact word) every few seconds a bit. Although CPU usage stays below 10% and memory is far from filled, it looks like it has not enough resources. Although that is strange since the program is from 2008, so if it worked back then you would expect that a 2011MPB must run it with ease.

    Does anybody have a potential solution to this problem?

    Thanks again!
  8. warvanov macrumors 6502a

    Oct 13, 2011
    I know this isn't the response you're looking for, but it sounds like you're creating a problem to find a solution to. If you were watching movies on your Mac then yes, you'd really want the left channel on your left and the right channel on your right. But for listening to music, it's less important that you be situated directly inbetween two speakers on your left and right. With the left and right channels both on your left in this scenario, the stereo seperation will still create a dynamic sound.

    When playing stereo music, your receiver is using Dolby ProLogic to create a virtual center channel and surround channel to create a dynamic soundscape that's greater than just sitting inbetween two speakers. If you reassign the left channel to occupy the two surround speakers and the right channel to occupy the right speakers then you'll be losing this feature. You also won't be getting sound from your center channel speaker (unless you assign the right channel to that speaker too, in which case you'll be getting unbalanced sound again.) Also, if your surround speakers aren't identical in size and wattage, or if your receiver is set to output to them at a lower volume, then you're still going to have balance issue.
  9. Pyromonkey83 macrumors 6502

    May 24, 2009
    In case you maybe didnt notice, he is using Logitech Z5500 speakers and has made absolutely no mention of a receiver. Z5500's certainly dont have DPL decoding built in, and without a receiver in the middle theres nothing to decode the DPL signals for the speakers.

    @OP, does it seem to happen constantly and regardless of media or is it only on some things?

    For example, try playing 320kbps constant audio (or 256kbps or whatever you have) and then try going on youtube and listening to a random video (128kbps). Does either cause it to stutter more or less?
  10. Masioni thread starter macrumors newbie

    Jan 19, 2014
    @warvanov: In my opinion stereo sound is a must when listening to music.

    @Pyromonkey: Different bitrates makes no difference.
    However, I discovered a strange phenomenon. As long as my screen is on Spotify (I have it running full screen), then there is no stutter. This leads me to believe that some other sound track or output is being activated at certain moments. As JACK audio only intercepts the Spotify signal, it may have something to do with that. Tomorrow I will try to fix this by first creating a single audiostream with all sound (system and apps) included using Soundflower. Then I will use that Soundflower output stream as input for JACK audio, and hopefully this solves the problem :)

    Thanks for the input again!
  11. warvanov macrumors 6502a

    Oct 13, 2011
    Amazon's description says that it does do DPL and DPL II decoding. I can't imagine a receiver that's capable of decoding DD5.1 would be incapable of DPL.

    Fair enough, to each his own, but to be clear you are listening to stereo sound even when you're not directly inbetween two left and right speakers. It sounds to me like what you need is a good pair of headphones.

Share This Page