Match Loudness and Match Clip Loudness

The supplimental [Loudness Normalization] Limiter included in the Match Loudness module makes all the difference. Basically Loudness Normalization is measurement, gain, and limiting (if necessary). When you define an Integrated Loudness target and a True Peak ceiling - the source audio is measured in it's entirety. Gain is added (or subtracted) based on the measured (I) loudness relative to the defined (I) target. If any such added gain results in True Peak ceiling overshoots - the limiter engages and maintains compliance. 

Consider this - you may have a finished piece for broadcast with ATSC A/85 compliance requirements (-24 LUFS/ -2 dBTP). You are also asked to create an alternate master for online streaming. Maybe -16 LUFS/ -2dbTP. That's a significant amount of supplimental added gain. Without the limiter (and of course depending on available headroom) - you run the risk of overshoots and/or clipping. 

In any case the multitrack Match Clip Loudness option (ITU-R BS.1770-3 mode) does not include an option to define a True Peak ceiling. If the source audio requires significant gain to meet your defined (I) target - there's no fail-safe. Overshoots, clipping, distortion, etc. (and non-compliance) may be unavoidable.

-paul.

@produceNewMedia. 

I don't think it makes any difference - unless you are desperate to play around with the minor parameters, of course.