Those “High Amplitude Audio Capture” microphones can record a significantly broader range of frequencies than standard microphones: up to 140 dB in fact, whereas traditional phone microphones top out at 110 dB. Decibels use a logarithmic scale, so that 30 dB difference is vast.
“To cope with high sound pressure levels, Nokia has developed together with microphone suppliers a new microphone concept (High Amplitude Audio Capture) that can capture high sound pressure levels with perceptually no distortion to the audio. It is capable of recording up to 140 dB and higher Sound Pressure Levels, while that commonly used digital microphones can only reach 120 dBSPL without heavy distortion. As high amplitude audio levels are tolerated, there is no need to limit the frequency response. Hence full audio bandwidth to match to human hearing capabilities can be provided when capturing with HAAC microphones” Nokia
The end result is audio more akin to what the human ear can hear, without the distortion common to most smartphone camcorder functionality. The Lumia 920′s three HAAC microphones are in the correct place for the system to work, we’ve been told.
Rich Recording isn’t mentioned by name in the data sheets SlashGear has seen – we’ve been asked not to publish them – but the key software specifications apparently match with those of the 808 PureView as well. We’ll be pestering Nokia for specific confirmation, but until then there’s more on Rich Recording in Nokia’s white paper [pdf link].