Elixir ITU True Peak Limiter

Certain ISP/True Peak Limiters provide added compliance processing flexibility. Case in point: Elixir by Flux.

Preparation

Before processing or Loudness Normalizing, execute an offline measurement on an optimized source clip.

An optimized audio clip may exhibit the benefits of various stages of enhancement processing such as noise reduction and dynamic range compression.

The displayed clip (see attached image) checks in at -19.6 LUFS. It requires +3.6 dB of gain to meet a -16.0 LUFS Integrated Loudness target. Based on the pre-existing peak ceiling approximately 1.5 dB of limiting will be necessary to establish a -2.0 True Peak maximum.

Processing Example

We use the Limiter’s Input Gain setting to take the clip down to -24.0 LUFS (-4.4 dB for the measured displayed clip).

The initial -24.0 LUFS target will restore headroom and establish a consistent starting point for downstream limiting accuracy. This will allow the Threshold and Output Gain settings to be recognized and implemented as static parameters for all -16.0 LUFS/-2.0 dBTP (stereo) processing. The Input Gain setting however will be variable based on the measured attributes of the optimized source.

Set the Threshold to -10 dB(TP) and the Output Gain to +8dB. The processing may be implemented offline or in real time. The output audio will reflect accurate targets (-16.0 LUFS/-2.0 dBTP) and the applied limiting will be transparent.

Note:

The proprietary functional parameters included on the Elixir Limiter are not necessarily included on Limiters designed by competing developers. In essence the described workflow may need to be customized based on the attributes of the Limiter.

The key is the “math” and static parameters never change, unless of course you decide to alter the referenced targets.

Let me know if you have questions …

-paul.

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