##Computer##ANSWER:
dark/light *self-explanatory*just sits there but frightens novicesCOMPUTER
I am seen in darkness and in light,
adjustable volume*not sure*literally, can be seen in dark/light
I am calm yet tend to fright.
multi-functionalfunctions based on logic; can play various games on itjust sits there but frightens novices
I can be quiet, I can be loud,
easily identifiable; conspicuoushave to interact with it to get informationadjustable volume
I hide in shame, yet am so proud.
basically they are everywhere one goesan obscure subset of people wishes to stay off the gridnot sure
I can be different, but still the same,
programs can be written to make it do anythingdepending on complexity, from one to unknownmulti-functional
I am straightforward yet am playing games.
operates on logic; can play various games on it
you can easily find me,
easily identifiable; conspicuous
but you'd have to look and see.
have to interact with it to get information
I am found everywhere I know,
they are globally ubiquitous
but why is it sometimes not so?
obscure subset of people wishes to stay off the grid
So many things that I can make,
programs can be written to make it do anything
but how many tries will it take?
depending on complexity, from one time to unknown