With all the modern marvels that have been introduced in the last decade for our studios it may seem strange that the microphone has changed the least.  A quick peek to the high end shows that some microphone designs used today were formulated in the late 60's, that's forty years ago!  Since then countless models have been introduced, copied, resurrected and repackaged with small refinements.  Few areas of the recording studio have been as hotly debated as to which is "best" for a particularly recording application.  Some of this is hype and some of this is not and it can be difficult to sort through the mazes of issues.  What I hope to do here is to give you some common references so you can at least talk about mics and their differences, and give you a useable roadmap for making decisions

Like any other piece of gear, the same microphone can give tremendously different results depending on how it is used.  There is a bit of expertise and experimentation that needs to happen when placing the microphone to capture a source.  Even the best mics in the world will sound boomy and unusable if the vocalist gets too close.  This same mic might fail miserably if recording an acoustic guitar if placed too far away, or off axis (angled away from the source).  An inexpensive mic, placed optimally for the task at hand can capture exceptional nuances, and once a track is treated with EQs, compressors and plugins, the results can be outstanding.  Yet a great mic. with an excellent preamp, given the same care during setup and post-treatment can be absolutely stellar. 

The Electrovoice RE20 is one of my favorites

Like anything worth doing, getting the best results takes a bit of practice, experimentation and work.  Yet the chances of getting a great take are consistently better with a high quality microphone.  Yet price and quality do not always match.  More so in the area of microphones than any other piece of gear, you can spend a lot of money and get something that you don't like, or spend a modest amount to get something you like a lot.  Microphones are priced from $50 to over $2000.  I would not recommend getting anything less than the Shure SM57 or SM58.  These mics will set you back $100 - $125 but the quality/price ratio is great.

I started my mic cabinet with the legendary workhorse, the all-purpose stage hammer, yes, the Shure SM57.  If it's all you have, you can use it to record everything, though for vocals and acoustic guitars, it is happiest with a good preamp.  For recording your amp or really loud stuff, it will resist breakup even under extreme pressure.  For vocals my first condenser was a Rode NT1, which is now replaced by the NT1a.  Once you have both a dynamic and a large condenser working for you, you have a lot of recording ground covered well.  Condensers shine on vocals, acoustic stuff--anything that has lots of high crystalline frequencies.  A third mic for me was a small condenser--the Shure SM81.  More expensive than many, but I wanted high quality acoustic guitar recordings.  Those 3 mics make a great basic mic cabinet for a home studio.

I should point out that microphones sound better with excellent preamps.  To get the full subtlety and nuance that a fine mic provides, it needs clean, quiet, gain, or amplification.  But you will hear a huge difference between condensers and dynamics even with the cheaper preamps tacked on to audio interfaces.

Setting up Microphones
Is this an art or a science?  A little of both, but often, just a matter of experimenting till something grabs you.  Consider the microphone to be an ear.  To hear the finest nuances of any instrument, you have to point the ear in a way that the sound vibrations "hit" the diaphragm of the mic jus right.  So I put my wave recorder in record and go to the instrument, play some hits, move the mic, play some hits, move the mic, play some hits---get the idea.  When I get back to the waveform editor, I will find that one position sounded better than all the rest and within that position there is one sample that rings clear and true with unmistakable quality. 

Matching the Microphone to the job.

Vocals  The human voice evokes our attention like no other sounds.  Are ears are acutely sensitive to very tiny inflections in the air around the vocalist. The goal of the microphone is to capture the innermost soul of the vocal.  Our ears are conditioned to want to hear a slight treble presence coloration on a typical voice.  So accuracy alone  is really not the name of the game hear.  Its accuracy plus good sounding coloration with high definition presence that is not bright, but warm.  Large capsule condenser microphones often get the call for their clean and aggressive high frequencies.  So do dynamic microphones, especially with vocalists that have strong powerful voices.  Condensers can distort if a loud vocalist gets too close.  Dynamics are also a good choice for rooms with a lot of ambient noise.  In fact, if you are recording in an ugly sounding reflective room, you have a good argument for choosing a quality dynamic mic to minimize interaction with the room.  There are also ribbon microphones, which may also be used for vocals when you need a rounded "natural" sound.  Ribbon mics require stronger preamps like the dynamics and benefit from variable impedance (a high end feature) on preamps.  Ribbons are also more delicate and require more handling care.  They can sound "dark" on "average" preamps. They are also expensive.  As you start your mic collection focus on dynamics and condensers, save the ribbons for later in the game when you have a great preamp.

What you need to watch out for when buying your first Mic

Assuming you understand the basic mic differences, make sure of two things before you buy. 

1. If buying a condenser mic, be sure you have +48v phantom power on your preamp.

2. If buying a dynamic mic, you don't need phantom power, you need gain on your preamp.  The SM57 and other dynamic mics need plenty of gain to get a good level, about 55-60 db.  Some of the newer inexpensive audio interfaces are designed for condensers which need about 40-45db.  Most mixers can handle the SM57.  A typical preamp with 60db of gain is fine.  If all you have are the preamps on your gain-challenged audio interface, and you can only pop for one mic, make is a large condenser.  On a budget around $100 smackers, the Studio Projects B1 is perhaps the best game in town. 

3. Avoid buying used microphones if you can but in particular avoid buying a used ribbon mic as these are susceptible to damage due to misuse more than a dynamic.

Acoustic instruments   I can talk about acoustic guitars best as I have been recording them a long time with numerous techniques and types of microphones.  I shoot for 3 things when recording acoustic guitar.  The sound of the pick hitting the strings, the "wooden" sound of the body and a sense of pressure and movement coming from the strumming hand.   Traditional techniques such as the X-Y technique, where two mics have their capsules very close (without touching) pointing to the instrument at a 90 degree angle from each other.  There is also the ORTF technique, where the mics cross each other ay a 110 degree angle, (instead of pointing at each other at a 90 degree angle like XY) which is good for recording at a greater distance, like in front of a stage.  I also record multiple takes with the same mic and pan hard left and right for a wide full sound.  Experiment.

All these choices!  The difficulty for many startup home studios is deciding whether to go with just one super quality microphone or getting several less expensive mics.  If your option #1 was to get the Neumann U87, for the same money you could get a CAD e200, Sennheiser MD421II, a Shure SM81 LC, an AT 822 stereo, and half a dozen SM57s, enough to get a pro studio off the ground.  But a home studio doesn't need lots of mics, particularly if you are not recording drums. In that case, maybe just a couple of good ones will make on happiest in the long run.  Another buying issue is going with a lower cost large condenser, say, the Rode NT1a.  If you one day decide to get a better large condenser, the Rode may become unused or a dead investment.  Fortunately, mics, unlike synths, samplers and computers,  retain their resale value quite well, especially on the higher end.  Some solid advice for a newbie is to get a Shure SM57 first.  It will do it all.  Then as funds permit, get a large condenser for vocals, a small condenser for delicate instruments.  You will have the majority of recording situations covered and you will appreciate how each different mic contributes its own signature to the final mix.