There’s loads of threads here on the forums and over on the blog.
Short answer:
1) Studio monitors are speakers designed to have a totally flat frequency response. Primarily targeted to be used in studio (go figure) environments where any sound coloring by the speaker is to be avoided and 100% natural reproduction is called for. Typically not made to listen to at high volumes for prolonged periods of time. Also have a tendency to be ‘tiring’ to the ears. Not made to take with you, exposed cones (speaker foam, grills all have an effect on the sound).
2) I am assuming with ‘speakers’ you mean any speaker not in one of the two other categories, like home and computer speakers. In general they are designed to make a pleasant sounding reproduction. Depening on type and model, they can either be built for bassy sounds, loud sounds, etx. Too many different kinds around to really say anything in general. Usually protected cones (grill, foam), but not suited for life on the road.
3) PA speakers. Made for the purpose of bringing music and speech at high volume levels for a prolonged period of time. Made of sturdy materials, lots of protective measures to prevent damage. High sound pressure levels are more important than high fidelity (although better PA systems will get excellent sound quality). All kinds of things (bolt eyes, tophat stand adapter, professional connectors) to make the systems sturdy and secure in operation.
Hope that helps some.
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