So how come that when I add an isolation pad to my CD player (and amp) the music sounds significantly better then? (...) As far as I can see: Better laser precision = better reproduction of the audio stream.

No, because the laser on a CD player is not analagous to the needle on a record player. The laser has nothing to do with the audio quality.

As long as the laser is able to extract the data from the CD without errors, it doesn't matter how precise or suceptible to vibration it is. That's the whole point of a digital audio system: The responsibility for sound reproduction lies with the DACs and the amplifiers, not the transport mechanism.

Now, I will grant that if the laser is getting errors when it extracts the data, your sound will suffer. But unless something is radically wrong with your CD player or the CDs you're playing, they shouldn't be getting any errors at all. And when they do get errors, they'll manifest themselves as things like skips, not as soundstaging problems.

If adding your special "isolation pad" genuinely improved the sound, then I suggest that there was something else wrong with your system which was causing other problems. Perhaps a ground loop between the CD player and the amplifier, or a loose wire which got reconnected better as a result of you moving the components to insert the isolation pad. But simply preventing vibrations from reaching the CD player shouldn't have any effect on the sound as long as the data is still being read off the CD without skips. A CD player is not a turntable, and there is no need to isolate it.

I submit to you that in a proper, randomized, double-blind test, you wouldn't be able to tell the difference between the presence or absence of the isolation pad.

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Tony Fabris