Buzz and Hotdog are both right, but it was a combination of things that led programmers to do the speed up bit. Sounding brighter was the usual excuse I heard. Putting more things, be they commercials or music in an hour was another. Invariably they discoverd that the pitch increase was a turn off for the audience. The latest hardware that seems to subsribe to the time compresion idea is designed to fill in the spaces, without increasing pitch. It's similar to the way delay units build up time when first turned on. A discriminating listener especially if they know the material can note and probably be agravated by what is happening. Such hardware and thinking comes and goes every few years. Those who fail to study history will make the same mistakes again and again.