One of the most interesting talks I heard at the Spring Noise Conference was a presentation about psychoacoustics and Dolby Volume. Dr. Poppy Crum gave a fantastic talk about how we hear, how our hearing changes, and audio illusions. If you’ve never heard an audio illusion, check out the Virtual Barbershop (make sure you use headphones). You can Google it or find it on YouTube here: http://www.youtube.com/watch?v=8IXm6SuUigI&feature=related
Dr. Crum works as a senior scientist at Dolby Laboratories, and Brett Crockett, the Director of Research, joined her to talk about Dolby Volume. Dolby Volume is a new product from Dolby Laboratories used for volume control. It eliminates two of the biggest problems in audio control.
#1: Composers spend countless hours perfecting music scores for TV and movies. Every atmospheric sound is accounted for, right down to the wind blowing and the crickets chirping. When it comes to your TV volume, current audio control methods lower every component in the sound spectrum equally. Humans don’t hear that way, though. The threshold of hearing is higher at the lowest and highest ends of the spectrum. So when you turn down the volume, you’re actually losing parts of the sound score. Dolby Volume uses an algorithm to lower the volume in a way that makes sense for human hearing. So even when the cowboys are talking around a campfire, you can still hear the crickets chirping in the background.
#2: You’ve just got the volume perfect when suddenly- KABOOM- something explodes onscreen and shatters your hearing. Or a commercial comes on and it’s ten times louder than your show was, leaving you scrambling for the remote. Or people start whispering and you can’t hear a word they’re saying. Once again, Dolby Volume uses the threshold of human hearing to compress the amplitude range as much as you desire. So the louds are still loud and the softs are still soft, but the differences aren’t as dramatic.
I’ve heard both situations demoed, and the differences are obvious right away. Dolby has managed to use the natural process of hearing to create a better audio technology, and I highly recommend you take a look for yourself.
You can read more about Dr. Crum and her work here: http://www.springnoiseconference.com/2011speaker-PC.htm