As always, track times and links to artists will be added in comments as soon as I can. Please support the artists that appear in this mix if you like their work, buy some more. :-)
"An Isochrone curve is the curve for which the time taken by an object sliding without friction in uniform gravity to its lowest point is independent of its starting point. The curve is a cycloid, and the time is equal to π times the square root of the radius over the acceleration of gravity."