For the ears, you can listen to an audio recording of this presentation. [high fidelity audio playable under all personal computer operating systems via VLC media player, Microsoft Windows Media Player with the Xiph.org codecs for FLAC et al, OS X QuickTime with the XiphQT plugin, etc., on many Android-based mobile devices, and on iOS-based mobile devices via apps such as FLAC Player or Golden Ear]

Much of the information you can see from an earlier presentation by Gina Upchurch remains true, with the obvious exceptions of statistics and costs from 2011. Listen to the audio recording for 2017 vintage data.