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  • Reverberation & Pre-Delay (ITDG = Initial Time Delay Gap

    I wrote a little text for a friend and post it here as well...


    Reverberation & Pre-Delay (ITDG = Initial Time Delay Gap) for Concert Hall Reverberation Programming

    The Pre-Delay, (ITDG) is the time between the arrival of the direct signal and the arrival of the first strong reflections. The Pre-Delay ((ITDG) setting in an artifical reverberator is not the same as in a real room, because only a fixed initial time delay can be dialed at one time. However, in a real room, every source at different location on stage produce different pre-delays. So vary the pre-delay settings for different instruments a tiny bit. Here the basic idea:


    Hearing of Distance in a Large Room

    Long Pre-Delay:
    A balance of direct signal level with low room reverb level and a long time delay gap (i.e. 18 ms to 45 ms predelay), as well as a long reverb time (RT), result in the impression of a close acoustic source in a large concert room. This is possibly the common way when using VSL samples.

    Short Pre-Delay:
    A balance of direct signal with higher room reverb level and a short, hardly recognizable, time delay gap (i.e. 15 ms pre-delay), as well as a longer reverberation time, result in the impression of a far acoustic source in a large hall. Naturally also the portion of higher spectra will be less.



    Hearing of Distance in a Small Room

    Short Pre-Delay:
    A balance of direct signal level with low room reverb level and a short time delay gap (i.e. 10ms to 40 ms), as well as a longer reverberation time (RT), result in the impression of a close acoustic source in small room.

    Null Pre-Delay:
    A balance of direct signal level with high room reverb level and no time delay gap, (0 ms pre-delay) as well as a short reverberation time (RT), result in the impression of a far acoustic source in small room.

    .

  • Good advice, Angelo. Thanks for sharing.

    /Dietz - Vienna Symphonic Library
  • Dietz, thanks. I had it corrected by people with proper english skills, here the latest version:


    Reverberation & Pre-Delay (ITDG = Initial Time Delay Gap) for Concert Hall Reverberation Programming

    The Pre-Delay (ITDG) is the time between the arrival of the direct signal and the arrival of the first strong reflections. The Pre-Delay setting in an artifical reverberator is not the same as in a real room, because only a single fixed initial time delay can be dialed at one time. However, in a real room, every source at different locations on stage produce different pre-delays. So vary the pre-delay settings for different instruments a tiny bit. Here is the basic idea:

    Hearing of Distance in a Large Room

    Long Pre-Delay:
    A balance of direct signal level with low room reverb level and a long time delay gap (i.e. 18 ms to 45 ms predelay), as well as a long reverb time (RT), result in the impression of a close acoustic source in a large concert room. This is possibly the most common way when using VSL samples.

    Short Pre-Delay:
    A balance of direct signal with higher room reverb level and a short, hardly recognizable, time delay gap (i.e. 15 ms pre-delay), as well as a longer reverberation time, will result in the impression of a distant acoustic source in a large hall. Naturally also the portion of higher spectra will be less.

    Hearing of Distance in a Small Room

    Short Pre-Delay:
    A balance of direct signal level with low room reverb level and a short time delay gap (i.e. 10ms to 40 ms), as well as a longer reverberation time (RT), will result in the impression of a close acoustic source in small room.

    Null Pre-Delay:
    A balance of direct signal level with high room reverb level and no time delay gap, (0 ms pre-delay) as well as a short reverberation time (RT), will result in the impression of a distant acoustic source in small room.

    .

  • PaulP Paul moved this topic from Orchestration & Composition on