Here is a contrarian thought:
As we know them, the world probably does not need another audio store. So the short answer to your question is: you probably are crazy.
But it seems to me that more and more and more and more people want some sort of multi room, home theatre, media servers wireless networks streaming digital music etc.
Simultaneously, there are no strong brands in the eyes of the mass market, other than perhaps Sony, Bose etc.
Amar Bose is worth a few hundred million bucks.
If I were you, and I were really thinking BIG, I would think about presenting all of this technology in a new, exciting context and/or building a brand for people who CAN AFFORD IT.
NOT for audiophiles who are too smart, too fickle, and less likely to pay high margins to someone who in their opinion probably knows less than they do.
So to set up shop trying to convince people to listen to music and buy geeked out high end equipment? Hmmmmm.....that one might not impress the business schools.
But certainly, there is a way to get rich and have fun selling consumer electronics but I would start by thinking "out of the box"
Best of luck.