Paul A Teseny Posted the following question or comment:
Hello Bob,
I hope you are well.
I have a question regarding your document “Level Practices Part 2”. In this document you talk about the Magic of 83 dB.
In your document “An Integrated Approach to Metering, Monitoring, and Leveling Practices”, you discuss the magic of 85 dB.
So, which is it? I can perceive the 2 dB difference when playing pink noise.
Of course, all of this assumes that the recorded material was properly mastered.
Thanks for your help.
Kind regards,
Paul
Dear Paul:
The history of the 85 versus 83 issue is a long one.
In summary, they are BOTH THE SAME. Depending on what type of pink noise you use and how you measure its amplitude, and what method you use to measure the SPL.
I use flat true RMS, unweighted to set the electrical amplitude of the pink noise to -20 dBFS, using gaussian pink noise. I use C weighted slow to measure the acoustic level.
Then, Dolby discovered that their historic 85 was really 83 using the above method! So they fudged their pink noise generator using an AVERAGE reading rather than an RMS metering, and meters to give the Hollywood people back a reading that says 85! Only the Dolby gear will get you an 85 measure with your sound meter. No one else is allowed on the playing field :-(. It’s all a fudge.
You can learn more by reading the article on this site called Level Practices.
Best wishes,
Bob