The problem statement, all variables and given/known data I've been reading up papers about mapping sounds to their auditory representation, and I'm a bit confused about one bit. They've given some diagrams of sound waveforms spectral with the y-axis being spectral frequencies, and the x-axis being temporal modulations. What are temporal modulation frequencies in this case? I've been trying to find a simple, down to earth explanation on the net, but there seems to be a few different answers, and I'm not quite sure which one it is, if any. Here is an image of what I'm on about. http://www.labgrab.com/files/science-news/images/Jack%20Payette/neuroscience_sounds.png?1358798270 If someone could give me an answer which an everyman can understand, I would be most grateful! "Spectral frequencies between 2500 and 5500 Hz, and temporal modulations in the range 1–16 Hz" - if that helps. Thank you!