Mastering engineer Ian Shepherd presented a MeterPlugs paper on Peak to Short-term loudness Ratio (PSR) – a new method of measuring musical dynamics for optimal online playback – at the 143rd AES convention in New York last month.
Shepherd was lead author of the paper, which is a collaboration with Ian Kerr (MeterPlugs), Eelco Grimm (Grimm Audio), Paul Tapper (Nugen Audio) and Mike Kahsnitz (RTW).
Optimising loudness while making full use of the available dynamic headroom is the new goal for major streaming services as loudness normalisation quickly becomes the norm. To help with this task, the authors of the paper have proposed that PSR can allow engineers to easily visualise short-term musical dynamics, and optimise audio for delivery on streaming services like YouTube, Spotify, Pandora and TIDAL.
Plugins like MeterPlugs Dynameter and Nugen MasterCheck already display PSR, yet different manufacturers use slightly different methods to calculate this. To avoid confusion, the contributors to this paper are working together to standardise the details.
"Our experience is that PSR meters like Dynameter are highly intuitive and immediate, giving real-time feedback and allowing engineers to quickly and easily achieve the results they're looking for," said Shepherd, who also spoke on Bob Ludwig's "Platinum Mastering" panel at AES this year. "Our users tell us they love being able to mix and master with more dynamics while being confident that their music won't get turned down online, and even stand out more as a result."
"Our hope is that by defining and standardising PSR, we can encourage more people to start using these meters," added Ian Kerr of MeterPlugs. "Measuring micro-dynamics is an exciting new area with plenty of scope for development, and we believe that collaborating with Grimm Audio, Nugen and RTW will lead to a robust standard and encourage future adoption."
The full title of the eBrief is "Measuring Micro-Dynamics—A First Step: Standardising PSR, the Peak to Short-Term Loudness Ratio" and the paper is free to download for all AES members here.
(Pictured L-R: Mike Kahsnitz, Ian Shepherd, Eelco Grimm, Paul Tapper)