Looking for a free DD tone generation method...

Discussion in 'Archived Threads 2001-2004' started by Robin Smith, Jul 18, 2002.

  1. Robin Smith

    Robin Smith Stunt Coordinator

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    Hi,

    I recently finished my DIY sonosub and am looking for a *free* way to generate tones for playback in dolby digital mode in 1 hz increments so I can graph the performance of my sub.

    Any ideas?

    I downloaded the shareware NCH tone generator which lets me save a wave file but I don't know how to burn it to disc in a way that will be read by my receiver (Denon 1802) in dolby digital mode.

    Any help/ideas would be appreciated.

    Thanks


    Robin Smith
     
  2. warrick

    warrick Stunt Coordinator

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    Hi Robin,
    First of all do you have a burner ?
    If so generate the tones with NCH tone generator and save them as .wav files on your hard disc. Make them 30 seconds long, this will give you enough time to take measurements.
    You can then use software like nero to burn them to disc, the wizard will guide you through the creation of an audio disc.
    Also if you match the Hz with the track numbers it will be easier to find them using your remote.
    You can get a demo version of Nero here
    This is what I did and it works fine.
    If you are wanting to create something that will play on all channels separately then you will be better off purchasing Video Essentials or Avia.
    Regards
    Warrick
     
  3. Mark Tranchant

    Mark Tranchant Stunt Coordinator

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    Robin - you don't need to burn it as a DD file. Burn it as a standard PCM stereo file, and connect the sub to one of the tape monitor outputs on the Denon, which should downmix 5.1 to stereo.

    Alternatively, if the Denon has a 5.1 or 6.1 pre out, set the main speakers to LARGE and connect the sub to either the L or R pre-out. As you'll be burning a mono CD, it doesn't matter which.
     
  4. David_Rivshin

    David_Rivshin Second Unit

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    If you just want the raw frequency response of your sub then why not just bypass the receiver all together and connect the analog output of the CD player to your sub? This also allows you to put different tones on the left and right channels (say pure sine vs warble), and connect whichever you want to your sub. Keep in mind, however, that you can't measure your mains response with such a disk, since the they'll each end up playing different tones and will give meaningless results.
    If you want to check the response including the crossover then connect your sub as usual and disconnect your main speakers. Getting a full set of readings (pure sub, pure mains, sub with xover, mains with xover, and sub+mains with xover) is alot of cable swapping and a whole lot of time. But it does definitely gives you a good idea of how your system is acting [​IMG]
    -- Dave
     
  5. Robin Smith

    Robin Smith Stunt Coordinator

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    Aha
    I was obsessing about doing this measurement in dolby digital mode.

    So it doesn't matter how I make the sub play back the tone, just what the relative performance in db of the sub from tone to tone is, right?

    The curve mapped using Mark's method (thanks Mark) would be the same as a curve mapped from a LFE channel if I had the capabaility of doing the tone generation through the .1 of the 5.1, right?

    Just confirming cos I think the light bulb finally came on over my head.

    Thanks


    Robin
     
  6. Mark Tranchant

    Mark Tranchant Stunt Coordinator

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  7. Chris Tsutsui

    Chris Tsutsui Screenwriter

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    Free?

    Hook an electric piano to the receiver and play the bottom note (which is 20hz) and then move up from there.

    Hook a MIC up to the speakers and use your vocals to produce various tones.

    Actually what I do is hook my PC (which has 6.1 pre/amp out from sound card) and then I download test tone MP3s. Then I'm able to output the signals to the speakers. There's no need for making a CD if you have a sound card that's capable enough. It may be a hassle if your computer is in a different room.
     
  8. warrick

    warrick Stunt Coordinator

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    Hi Robin,
    If you are looking for some downloadable tones in MP3 format I have just rediscovered the site
    http://www.snapbug.ws/bfd.htm
    Its all about setting up a BFD but half way down is a link to the tones.
    Very interesting site on its own
    Regards
    Warrick
     

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