Here are links to the files online (or see attachment below):
K20D.mp3 ist DS.mp3
Here a recording of the 2 cameras. I did this with the lens cap on- the camera is hunting from infinity to close focus and back. I have to say that the DS sounds even quieter in the real world, maybe my program turned up the volume a bit. Do you hear the same when you use your K20D?
What is also interesting is that the motor of the K20D is quite a bit faster. It takes the DS 0.7 seconds to reach closest focus, the K20D only needs 0.4 seconds. The delay to focusing back is 0.375s for the ist DS and 0.275s for the K20D.