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Stereo for a small theatre presentation? Good/Bad?
  • Hi,

    I'm unexpectedly having an amateur film (more a labour of love really) screened in a small local theatre next week. I didn't really prepare the audio for theatre presentation - it's just a stereo mix, and I don't have any experience in mixes for theatre presentation.

    I'm not interested in a 5.1 mix, but should I be worried about not using the centre channel? The threatre seats around 150 people, but it's quite narrow - typically 11 seats across (see picture).

    Thankfully we do have the opportunity to test the screening this week. Delivery format can be DCP or Bluray.

    So I think my options are:

    • Put the "stereo" mix in DCP, which will probably be encoded LCR, with no centre - will this sound odd? Plus, to be honest, DCP is probably overkill.
    • Put the stereo mix into Bluray encode - I have no idea if a stereo mix will just use the left/right channels, or if the cinema system will output a L+R mix to the centre. Needs testing
    • Create an LCR/5.1 (no surround or LFE) by either:
      • Creating the centre mix by adding the left and right channels (-3dB on each, or -3dB on total?)
      • Re-rending my audio as a "background/music" stem and a "dialog/foley" stem and create a mix that puts the dialog on centre, and the backgrounds on the L/R. Is it worth the time to do this? And if I do this should the placement onto the speakers be hard, or should I let a little of the music onto the centre and a little of the dialogue on to left and rights?

    Any advice very much appreciated!

    Clapham_Screen_2.jpg
    240 x 164 - 17K
  • 3 Replies sorted by
  • In all likelihood the theater will simply decode your stereo soundtrack as Dolby Pro Logic, and properly place centrally-mixed dialog in the center channel. If you panned dialog left and right in the stereo mix, the Dolby decoder will accurately put it in the left and right speakers. But if you did what most do and left all dialog in the middle of the stereo mix, you should be fine. If your test screening tells you they're just piping the stereo mix to the theater's left and right speakers, let them know politely that they should be treating all 2-channel film sound as matrixed Dolby Pro Logic for multi-channel playback.

  • Most modern DCP servers use SMPTE spec that has option to encode regular 2-channel stereo.

  • Thanks for the responses guys.

    I've left all the dialog in the middle of the stereo mix (aside from one or two instances where there are off-screen characters, that have a gentle panning) so it sounds like it should be fine - but the test screening will reveal all :)