To further answer your question on how to build a music studio we shall talk about selecting studio monitors. Now that you have a good computer, recording software, audio/midi interface, and a condenser microphone, next on the list is a pair of studio monitors. Personally, I like those that are already powered (active monitors) which means that I do not have to buy a separate amplifier. But the choice is yours as to whether you should buy passive monitors plus an amplifier or just go with the powered ones.

How to build a music studio - selecting studio monitors.

What you need is a near field monitor. What is that? It's a monitor that you keep close to you. If you move around a room you will notice that the sound changes a lot as you move. This is because of room acoustics. So depending on where a speaker is placed (the corner or center of a room for example) and where you're standing, it will sound differently. With a near field monitor you will be able to accurately measure the sound you're creating. And since your speaker is close to you (between 3 and 5 feet), you do not need much volume. With less volume the sound won't bounce around the room.

The studio monitor must be able to paint an accurate picture of the music. In theory, they should be flat or unnatural, meaning that no frequencies are emphasized or de-emphasized. In practice, lots of people do the opposite, particular with the bass, and subwoofers are used. Just ensure that you keep the subwoofer volume low or else your final mix will be bass-shy. The bottom line is that with your mix should be so good that it will sound good on the worst of music systems. It's all about your experience and skill.

How to build a music studio - buying studio monitors.

A good set of monitors can be found online for between $400-$800. I wouldn't suggest that you buy something cheaper. Your monitors are really your ears into the computer. It would be better to save up some more money rather than buy something that you will regret buying.