What is DR?
The DR algorithm, akin to PLR (Peak–to–Loudness Ratio) or “crest factor,” specifically measures the dynamic density or lack of dynamics caused by overly aggressive dynamic compression and limiting. Although the companion DRMeter provides an estimate of the "official" DR Value, only the DROffline utility can generate official values, which are cumulative over the entire length of a song. Only DROffline can scrub through an entire song or track, resulting in an official DR number.
The complete DR metering system, composed of the real time DRMeter plus the DROffline batch processor, was created by Friedemann Tischmeyer to address the need to generate a repeatable, easy to understand numeric value. Seeing a meaningful and easy to understand indication of dynamic range inspires users to back away from hyper compression.
Is there a good reason to use DR?
Unlike R128 and BS. 1770 meters, DR measures dynamic range from the perspective of a music engineer’s needs. In contrast, R128 and 1770 are designed to control loudness for commercials, not measure dynamic range for music, especially pop music. DR isn’t designed for broadcast loudness control, it’s purpose is to gauge the amount of dynamic range reduction, or the absence of dynamic range contrast. Designed by a member of the EBU ploud committee, the same body that created R128, DR informs an engineer about how much the mix is being or has been “stepped on,” dynamic range-wise, not about “will it pass through a broadcast chain without loudness reduction?”