Boundary Condenser
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 Sennheiser e901 Boundary Condenser Mic  US $239.95
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 Sennheiser E901 Condenser Boundary Microphone US $239.95
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 Shure Beta91A beta91 A Boundary Condenser Microphone US $239.00
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 AKG C680BL Small Boundary Layer Condenser Microphone US $100.00
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 Audio Technica AT871UG Unidirectional Condenser Boundary Microphone US $100.00
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 Crown MB1 Condenser Boundary Microphone US $99.99
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What is a condenser boundary mic??
and whats better to record live music by just placing a mic in front of the band, a "condenser boundary mic"
or a stereo mic
Microphone Essentials
Microphones are an essential piece of the overall sound puzzle. In this installment we are going to look at the absolute basics of microphones and microphones and usage. This no-nonsense look at microphones will barely scratch the surface of what is available in microphone options, technologies and applications.
When doing home recording you need to be aware of equipment limitations. If your signal chain consists of a lot of low-dollar hardware and software then the best and most expensive microphones will give poor results (expensive is relative as studio microphones can go into the tens of thousands of dollars). The smart way to choose a microphone is found in our motto "begin with the end in mind."
Most of us will be recording ourselves and will have a specific style of music to record. If we have that settled then we can begin thinking about mic selection, but before we get there lets get some basic understanding of microphone types and some key terms down.
The transducer is the device within a microphone that converts the analog sound of the voice or instrument to a voltage that can travel along the signal path. There are 3 types of transducers for microphones: dynamic, ribbon and condenser.
A dynamic microphone has a small diaphragm that is suspended in a capsule surrounded by a coil. When the sound enters the capsule the diaphragm vibrates moving the coil over a magnet to produce voltage. The dynamic mic is used most commonly as an instrument and performance vocal mics. 2 well known microphones of this type are the Shure SM-57 and SM-58. Dynamic mics are known for their durability and multi-purpose use.
Ribbon microphone works the same way except instead of a diaphragm it has a thin piece of foil material that is suspended in the capsule that vibrates within the magnetic field to produce its voltage. Ribbon mics are not durable, but are great for studio applications because they are warm and very smooth sounding. Mostly used for vocals and acoustic instruments but must be used with care as it is relatively easy to "blow-out" the ribbon.
Condenser microphones have no coil and require a power supply to operate the diaphragms to produce the output voltages. It can come from an internal battery (placed inside the microphone housing or an external phantom power source. Phantom power is +12 to +48 Vdc and can be supplied by either an external power module or from the mixing console. Many of the inline mic preamps we look at in a previous article have built in phantom power. Some condensers can run on as little as +3Vdc though not with practical results much better than a dynamic transducer. Condenser mics have a variety of uses and applications because of the external power needed examples would be vocal mics, studio mics, choir mics, lapel and headset mics, etc.
Diaphragm size generally will dictate a purpose of a particular condenser mic, but as you will learn in the studio there are no rules and what rules the experts write are written to be broken. Hear is a rule of thumb, the larger the diaphragm the more sound and frequencies it will capture and convert. Some sizes and uses would be a micro- diaphragm used in lapel and choir loft mics. Small diaphragms are generally used for acoustic instruments and cymbals. Medium to large diaphragms are used as vocal and ambient room mics.
The last item of importance in microphone essentials is polar pattern. Polarpattern is simply how the mic will receive sound relative to capsule position and distance. There are 2 patterns, omni-directional (picks up sound from all around 360degrees) and uni-directional (picks up sound from less than all around or less than 360 degrees. Uni-directional is broken down into 3 sub-types, cardioid, supercardioid, hypercardioid and bi-directional.
The cardioid pattern is a heart shaped pattern will "reject" sound that comes in from behind. This pattern is great for studio use if you have offending noise in the studio you just point the mic in the opposite direction of the sound and it will reject that sound coming in from behind.
The supercardioid will has more isolation than a cardioid, meaning a greater rejection area off to the sides between 120 to150 degrees also 210 to 240 degrees ideal for stage micing.
The hypercardioid mic has the most side rejection of any uni-directional pattern over a greater area and distance also ideal for stage and live recording situations.
Finally bi-directional rejects sound on the sides but front and back have the same pick-up characteristics. You would see this mic in tabletop interview situations and in special situations or in duet vocal applications amongst others.
Here is an article on Shure's website that can give some more information: http://shure.com/shurenotes/feb2003/mic.asp>. Almost all microphone manufacturers have some great articles and educational materials on their sites and Shure houses probably the best education and knowledge base section of all of them.
Note: The online html version of this article will have some pattern graphics added to it.
How To Choose a Microphone
Choosing a microphone is not a big deal if you do your homework. Also accept this fact, more money doesn't mean best microphone for you and your recording situation. The Beastie Boys had a hit using Radio Shack microphones that you could buy for $39.99. In home recording you will discover it is not always the equipment that makes or breaks the sound but how you use it.
Our first hard, fast and no fluff look is at vocal microphones. Your first consideration is the sound and tone of your voice. Microphones can enhance or take away from your natural voice characteristics. Microphone sound (color) characteristics can be anywhere from "brittle" (enhances high frequencies) to "boomy" (enhances low frequencies) or "muddy" (enhances mid frequencies).
If your voice is bassy you would want to use a vocal mic that will enhance highs and not the lows. Conversely, if you have a thin, bright sounding voice you will want to consider a mic that enhances lower frequencies (aka "warm").
One way to determine your vocal characteristics is to simply sing into a cassette recorder and simply listen. If you have any type of equalizer or tone (bass/treble) controls you can play with that and determine what you did to make your voice sound better. You can get a good evaluation by going to a local recording studio and spend an hour with an engineer there.
Next spend some time looking at microphone frequency response charts. These are graphic representations of tests performed on their microphones in controlled environment to give a basic, "what can you expect" guide to their products. Examples here are the Shure KSM27 studio vocal mic and the SM58 dynamic vocal mic:
You will notice on the KSM32 response chart below that this microphone has 3 different settings. Normal which gives a flat response on the lower frequencies and also a low frequency cutoff and low frequency roll-off. Microphones of this type are great when you need basically one mic for a couple of different voices or instruments.
It is true that you can use your equalizer to alter any mic characteristic, but it is always better to get the best sound you can without any processing then cut or boost as necessary.
Instrument microphones are really no different than any other microphone except you need to consider SPL (sound pressure level) when micing instruments, especially kick drums and amplifiers. SPL is the microphones ability to handle high-pressure sound waves (volume levels) without damaging or distorting the microphone.
Some people are under the mistaken impression that an instrument microphone can not be used as a vocal microphone. Case in point, an SM57 is considered an instrument microphone and an SM58 is a vocal microphone. The SM57 is every bit the vocal microphone as the SM58, why because they are the same microphone except the SM58 has a ball type grille on top and the SM57 has a flat or rather concaved grille. The only consideration is the way they diffuse air as it enters the grill. The SM58 will diffuse, designed for vocals and the SM57 will not diffuse but channel the air making it optimum for instruments. So an SM57 can be used as a vocal mic if you know to sing off axis (not directly into it). The SM57 catalog price is $79.99 and the SM58 is $89.99. Personally I have recorded vocals, acoustic and guitar amplifiers with an SM57. I also have wide open access to many high dollar microphones, but I like the SM57 and I use it the most.
If you get serious about recording, understanding microphones will be extremely important. Knowing how to use them will be key to using any microphone successfully and a future topic.
http://www.homestead.com/raywatsonsecretplace/Articles2/9-11_microphones.html
The Monkey Song
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