60's psychedelic instrumentals.
Play a loop of infrasound under the music playlist and see if that has the desired effect.
I'd suggest using the standard music from the period, but with one addition.
Infrasound - Wikipedia, the free encyclopedia
Some of these frequencies can cause feelings of dread that the listener can't put their finger on because they can't hear them. Play a loop of infrasound under the music playlist and see if that has the desired effect.