Jude (and others)
The isolation principle is a fairly sound concept <ugh, that was an awful pun!>. The idea is to reduce mechanical vibration interference from the environment and other components. It's greatest effect should be on your source as a lot of reading errors ("skipping") is the result of vibration. The theory is that the less vibration, the lower the error rate, the less error-correction you CDP has to do, and so the purer the sound.
WARNING: The following delves around the edges of the whole concept of "Psycho-acoustics" and should be taken as the author's own impressions and opinions only, and not the Gospel according to St Hamsta. The author takes no responsibility for, and actively discourages, the outlay of hard-earned dosh for isolation devices on the basis of this synopsis only without first hand listening experience!
My personal feeling is that different types of isolation as well as GENERALLY improving sound quality will probably impart subtle characteristics to the sound based on which areas they "clean up" better. This can appear as "deficiencies" or "colourations" because those areas less improved may stand out more. I have one mate who got a set of Vibrapods (see www.stoneaudio.co.uk
) and put them under his Cyrus CDP. Made his system sound slow and muddy, so he rapidly removed them and placed tham under his amp, effecting a modest improvement over the original set-up. Some feel that sorbothane feet give a more "laid back" feel while metal ones sound more "forward".
I use a Mission Isoplat (Duncan's MDF board with Sorbothane feet) under my CD63 and I agree it affects some improvement in the bass and soundstaging..... and for NZ$15 (about US$7) from a 2nd hand shop, who's complaining! My main hifi is in a dedicated tripod rack that is spiked to the floor with individually spiked MDF shelves. Here component seperation as well as isolation helps improve the sound.
There are lots of options - Sorbothane feet, Vibrapods, Metal spikes, Oak cone feet, Blu-tack!...... You can even make your own isoplat with a piece of MDF and two squash balls cut in half as feet. The best way is probably to experiment and find out what works for you and your gear. I'm going to be doing the same when Duncan's QED MB45 arrives as it'll have to sit on top of my CDP to conserve desk-space, and a little isolation probably won't go amiss. BTW, whichever system you use always make sure your components (and particularly your source) is LEVELED. Three points of contact is usually the easiest to sort out.
Anyway, enough waffle. You've probably heard it all before.
PS - Remember, don't take my word for it - check it out and decide for yourself. Cheers, H.