I'd like to just put in a positive word about Light and Sound machines.
I've long been curious about science that makes hypnosis easy - especially for those of us that are analytical or <insert reason> difficult to trance.
Bought myself an early christmas present and have been using it for the last couple weeks. Those that were good already subjects - simply telling them how powerful it was made for interesting trance session.
For me - I've found it very easy to float along with it. Time distoration especially happening every trance rather than sometimes.
Give it a go if you've not already.