The psychomanteum itself can be any space you can set aside for it.  It can be a separate building, a room in your attic or basement as is mine, the corner of your living room, or even a closet.  It is important to think of this as consecrated space.   You may want to perform a cleansing or purification ritual when you set it up and prior to each use.  Make your Psychomanteum a special and sacred space where you feel safe and comfortable.  Wherever you construct it, think of it as separate from everything else in your personal environment. It can be the place where you meditate or spend reflective time on a daily basis.  Keep your psychomanteum free of daily detritus such as newspapers, bill-paying paraphernalia or anything having less than peaceful connotations.

Since one of the keys is sensory deprivation, I do not recommend placing it in any area containing windows.  Any distraction is counter-productive.  If you can’t eliminate windows, make sure they have opaque coverings.  If it is in a public area, you may wish to think of it as a sanctuary which has been camouflaged from a hostile environment and reconsecrate it each time you use it.
constructing your psychomanteum