Yes, it's quite simple, and in fact Concorde also causes a double boom, but it has nothing to do with it being at Mach 2.0.
First, however, let me just make a point about answering questions like these.
Supersonic flight aerodynamics is an extremely complex subject, likewise the study of shock waves and sonic booms. Trying to answer questions about them on a general forum, asked by people whose level of knowledge is not known to me, is not always easy. I could be answering a fifth grader whose knowledge is very scant, an aerodynamics professor who knows lots more than I ever will, or any level of education in between .
I try to reply at what I think is an appropriate level, and often simplifications and generalisations are necessary, just to keep the answer to a reasonable length. However, until you get to know someone, the only real way of trying to assess what level is appropriate is to consider the language the questioner used.
In this case, Trent_800 referred to "the Boom", and so I left it at that, as the double boom doesn't have anything to do with going at Mach 2.
To answer your question, and again simplifying somewhat, there are two shock waves associated with a body in supersonic flight. The bow wave and the tail wave, which are attached, oddly enough, to the front and the back of the body. When these shock waves strike the ears of an observer at ground level, the ear detects them as two distinct sounds.
Those, like me, who have heard Concorde pass overhead at Mach 2.0, will tell you that they do indeed hear a double boom, as do people who are under the Space Shuttle whilst it is supersonic, but the double boom is not related to the fact that Concorde or the Shuttle is at Mach 2.0.
If an aircraft is going really fast, it is quite possible for both shock waves to arrive at the ear so close together that the ear cannot distinguish between them, and therefore “hears” them as a single boom.