Microphones - Recording Studio Microphones

Best recording microphones - Shure akg neumann mics

How mics work - How to choose a microphone
Building a home recording studio. How to record at home.
Setting up your home recording studio for a fraction of the cost.

A series of Articles on Basic Home Recording

Permission to reprint / edit has been granted. Please note: Some of the articles printed here are an abridged version of the articles Jim presented to the Sharesong songwriters group.

Part 3 - Standalone Recorders
Part 4 - Intro to PC Recording
Part 5a - Audio software - freeware / shareware
Part 6 - Introduction to Multitrack Recording
Part 7 - Audio Recording Software
Part 8 - Sound cards - Input Basics
Part 9 - Microphone Inline Preamps
Part 10 - Microphone Essentials
Part 11 - How To Choose a Microphone

Part 9 - Microphone Inline Preamps

If your soundcards preamps are noisy or low-volume you may need to add an external inline preamp to get true line level voltages. In such case you will no longer use the "mic-in" jack, but rather the "line-in" jack (see Part 8).

Inline preamps come in a variety of sizes with differing features. Below are some key features you would find.

1. Variable input and output gain controls
2. +10 up thru +20 dB gain up switch
3. +48v phantom power
4. VU meter (either analog or digital)
5. both XLR and ¼" balanced phono jacks.
6. Polarity / Phase Reverse Switch

To help choose what you should look at getting you again to need to know some basic terms and concepts.

The first would be to understand preamps can and will color your sound. Meaning if you have a nice warm sounding microphone and put it thru a preamp which has circuitry that produces a bright, thin sound you will not get good results. Same if you put the warm sounding microphone thru a very warm
sounding preamp you will get a big boomy, possibly muddy sound. This is where the term "transparency" comes in. Transparency refers to the sound coloration of the preamps meaning simply does the preamp change the sound that is coming into it. You might accept this fact now, no preamp on the consumer market for less than a few thousand dollars will be truly transparent. But having said that some are closer than others.

In choosing a preamp you need to keep in mind your vocal characteristics or whatever you will mic i.e. an acoustic guitar or a Marshall half-stack. Also keep in mind the microphones you are using, are you using dynamic microphone? Is it neutral sounding like a Shure SM-57 or is it fat and warm sounding like the EV N-dyn 767a. Are you using condenser microphones? Large diaphram or small? Is it a thin sounding mic or fat? Will you need phantom power, etc? We will get into microphones in another section. Your local pro-audio expert should be able to help you with your choice if you know what you are after.

There are 2 types of mic pre-amps you will encounter in your search, tube and solid state. The differences here are major and worth noting. In by common conception and old technology digital recording is considered to be 2 dimensional, flat, sounding digital. That is because analog signals contain what is known as harmonic distortions that seem to add life to a recording. Our ears are analog and when we hear sounds they are filled with harmonics giving us 3 dimensional hearing. So the digital recording world has had to overcome for the lack of harmonic distortions in digital audio. This is why
a Vinyl album will sound better than a CD of the same music. Though today's music buyers are not familiar enough with the analog sounds of vinyl to appreciate depth and sound placement, many home recording enthusiasts are and there is the where the debate as to which is a better medium to record
in, analog or digital.

Now a tube mic pre is designed to add harmonic distortion to "fatten" the sound by way of a tube altering the analog or digital signal. This is both good and bad. It is good because they will add grit to your vocal that will make it sound fuller and more natural. It is bad because it colors your vocal and what you get in your recording is what you get, you can't remove the colorations without affecting the vocal itself. The tube pre is a great way to go if you are using a very brittle (thin and bright) sounding microphone.

The solid-state preamp is opposite the tube in characteristics. It's purpose is to be transparent and not color the sound. This will allow you to process the vocal afterwards with plug-ins to add whatever you want retaining the original signal. You can add harmonic distortions after the fact with a tube compressor plug-in, but in the consumer realm this can lead to "processed" sound if the plug-in is not very good, you can also use inline outboard effects such as a tube compressor.

The waters are now muddied, which then is better? Neither and both, there is another technology that comes into play here and that is the analog-to-digital converters on your soundcard. We are not going to discuss this technology so we will go directly to where the rubber meets the road. how does it sound with your voice, your mic and thru your soundcard. What you are going to find in the consumer realm is all going to be subjective to your tastes.

Another source of preamps is a mixer. Of you have a mixer laying around you can use the mic and trim/gain settings there and use the mixers line out or preamp out.

Personally I use solid-state preamps that are found on my Aardvark Q10, they are fairly transparent giving me a lot of flexibility with different mics. I use a tube compressor on the mic channel insert to add harmonic distortions and I can season it to taste. Like anything else you can overdo it. When we discuss signal chain we will cover this a bit more in depth.

Here is a link to a Musicians Friend search I did on preamps. Listed are some of the more common preamps:

<http://www.musiciansfriend.com/srs7/sid=031226202629139055235230545094/g=ho
me/search/d=tp?q=mic+preamp>

Jim Goodman
http://psalm149.com
Songwriting and Home Recording Forums

Part 10 - 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.

Part 11 - 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:
<http://shure.com/images/response/fksm27_large.gif>
<http://shure.com/images/response/fsm58_large.gif>

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.
<http://shure.com/images/response/fksm32_large.gif>

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.

Basic Home Recording ©2003 by Jim Goodman. All rights reserved. You may download and reproduce entire document only for non-commercial purposes providing this copyright exists on all copies. All other uses require a written request to jgoodman@alltel.net or thru http://psalm149.com