What Microphone Do I Get?
by Jeff Towne
It’s one of the most common questions floating around radio-oriented
mail lists, discussion boards, and any time radio producers get within six
feet of one another.
If you’re in the mood for some details to get you started, here’s some info to help
narrow the search.
There are lots of different kinds of microphone types: dynamic, condenser,
ribbon, boundary, binaural, M-S and more. There are a myriad of pick-up
patterns, different-sized diaphragms, variations in frequency response,
sensitivity, self-noise, susceptibility to handling noise, wind or plosives.
The possibilities can boggle the mind.
Basically, they are all devices to convert sound pressure levels into
an electrical current. Dynamic mics’ diaphragms move a coil of wire near
a magnet, much like a small speaker in reverse. (In fact, if you wire a
speaker, or a pair of headphones, into a microphone input, either will perform
as a microphone–not a very good one, but either will act as a transducer
from sound waves to electrical impulses.) Condenser mics use “phantom
power” to create a charge differential between a suspended diaphragm
and a fixed backplate. In either design, as the diaphragm is moved by sound
pressure changes, the microphone translates that movement into electrical
Any decent music store or catalog will have a large selection of mics,
but most of them will be mics designed for fairly specific sound reinforcement
purposes or for recording of musical instruments. Some of these mics can
also be useful for collecting sound in the field, or recording voice tracks
in the studio, but conducting interviews and tracking narration have some
The most basic distinctions we are concerned with are between Dynamic
vs. Condenser, Directional vs. Omnidirectional, and Large Diaphragm vs.
Small Diaphragm. None of these choices is universally superior, each has
strong and weak points.
|Need no external power.
Handle high volumes well.
|Require Phantom Power
Shure SM-58, SM-57, SM-7
Electrovoice RE-50, RE-20, 635A
AKG 414, C-3000, C-1000
Neumann U-87, KM-series modular
Sennheiser K6-series modular
Condenser mics are often a little more expensive, usually have a louder,
more detailed output, but one should not overlook the benefits of dynamic
mics, especially in the field. Dynamics are MUCH more forgiving of rough
treatment, and do not require external power. Condenser mics break more
easily if dropped, and require phantom power to operate, which must come
from the recorder (draining batteries faster) a mixer, a preamp, or a separate
power source. And even in the studio as an announce mic, Large Diaphragm
dynamics such as the Electrovoice RE-20, Shure SM-7 and Sennheiser 421 produce
very high-quality results. In the field, the overall durability and lack
of phantom-power issues make dynamic mics very attractive.
There is often confusion between phantom power and preamplification.
Although many preamps provide phantom power, they are separate power streams.
All microphones require a pre-amp stage to raise levels approximately 60dB,
but condensers, and some other types of mics, also require a low-level current
to charge the diaphragm of the mic, setting up the electrical differential
between the diaphragm and the backplate of the mic. Most modern mics want
to see 48volt phantom power.
If your mixer or recorder will only turn phantom power on globally, that
is, to all channels, and you are using a mix of mics, don’t worry, the phantom
power will not hurt your dynamic mics. (Although it can create some noise
problems if applied to unbalanced line-level signals.) It is good practice
to only turn on phantom power after all mics and cables are securely plugged
in, and to turn off the phantom power at least a minute before unplugging
the mics. This is absolutely crucial if one is using ribbon mics, and good
form in any case.
Many condenser mics, especially those designed to be hand-held, can accept
a battery to provide the phantom power. This eliminates the need for an
external box if your recorder or mixer will not provide power, but also
adds another battery that can drain at the least opportune moment.
Condenser mics almost always provide a louder output, reducing the often
noisy preamplification stage. And condensers often give a brighter, more
Either type of mic can have various pick-up patterns. Some mics can be
switched to change patterns, or capsules can be screwed on and off, giving
greater flexibility. Of course, these mics are usually more expensive than
fixed-pattern mics, so if you’re on a tight budget, you might want to choose
a fixed-pattern mic that best suits your needs.
The most common directional pattern is called “cardioid” for
its heart-shaped lobe of maximum sensitivity in front of the mic. Sounds
to the sides and especially to the rear of the mic are largely rejected,
or at least attenuated. Hypercardioids have an even smaller, more focused
pattern, the most extreme example of which is the “shotgun” mic,
which is meant to be used at greater distances. It’s important to remember
that even the most directional mics do not completely reject sound outside
of the pick-up pattern. “Off axis” sounds are reduced in volume,
but also often acquire a phasey or muffled character, sometimes making
sounds seem rather odd. Sometimes, what’s most effective for one purpose,
such as reducing feedback on a noisy rock concert stage, is not as pleasing
for another, such as an intimate commentary in a quiet room.
The next most common pick-up pattern is called “omnidirectional”
for its ability to pick up sounds in all directions equally. Because of
the mic’s design, it has less of a focus on a particular direction, but
also, off-axis sounds are picked up more accurately and naturally, lending
a more realistic ambience. Some people mistakenly believe that omni mics
will pick up close and distant sounds equally, making the background too
loud compared to the primary source. But these mics must still obey the
laws of physics, and focus on the subject can be achieved simply by getting
the mic in close.
Both human perception of audio and the physical behavior of sound waves
are measured according to the inverse square law, which is to say that in
ideal conditions, sound intensity drops 6 dB (half the volume) every time
the distance is doubled, and conversely, the volume doubles as the distance
is halved. This gets more complicated based on the sound source and the
actual acoustical properties of the space, but it remains a good rule of
thumb. What this means for mic technique is that even an omnidirectional
microphone can focus on the close sound, because the level of distant sounds
decreases logarithmically with distance. And conversely, in most cases,
in order to get good sound on tape, one must get the microphone close to
the source because its sound pressure levels are dropping rapidly as you
lengthen your distance.
Omnidirectional mics have the added benefit of being less susceptible
to handling noise, and more tolerant of wind and plosives (popped “p”
sounds and the like) and less “boominess” when close to the source,
although, of course, not completely free from these problems.
Heightened focus on centered subject.
More rejection of ambience.
Needs precise mic placement, off-axis sources often sound bad.
More susceptible to handling noise, wind and plosives.Natural, “you are there” sound.
Picks up more of surrounding ambience.
More forgiving on mic placement, off-axis sounds are more natural.
Less susceptible to handling noise, wind and plosives.
Shure SM-58, AKG C-1000, Sennheiser ME64 capsule, shotgun micsCommon Examples:
Electrovoice RE-50, 635A, Sennheiser ME62 capsule, most Lavalieres
Does Size Really Matter?
Among the varieties of microphones covered above, there is yet another
distinction based on the size of the diaphragm. Dynamic or Condenser, Cardioid,
Omni, Figure-8 or other patterns, each of these can employ a large or small
diaphragm. In general, handheld microphones will have small diaphragms,
which are more durable, less susceptible to handling noise and air currents,
and well…gee…they’re smaller.
Large diaphragm mics are best suited for studio work in controlled
where they can be placed on a stand, preferably with a shock mount and a
pop-filter. The larger, more flexible diaphragm gives a richer, more detailed
sound with a higher sensitivity, and so is generally preferable for primary
announcing duties. Even in the field, if circumstances allow conducting
an interview while the subject is sitting in one place, it’s worth considering
bringing a large diaphragm mic, a stand and a pop filter, particularly if
the interviewee is used to microphones (an experienced public speaker, a
musician) because the overall sound quality will be better than with a smaller
hand-held mic. But these large-diaphragm mics are very susceptible to extraneous
noise and vibrations, and despite frequent claims by manufacturers of having
integral pop-filters, they always need additional foam or mesh pop-reduction
Small diaphragm mics can usually handle louder sources, and
actually can have a larger frequency range, especially in higher frequencies,
due primarily to the smaller diaphragm having less weight.
Be sure to read Jay Allison’s excellent Basics
of Field Recording column here in Transom Tools for tips on mic technique
and interviewing strategies.
I know, I know, after all this blather, I still haven’t told you what
mic to get. The best answer is for you to try out a few and see what mic
prefer for your style of reportage. The old reliable faves seem to be the
omni EV RE-50 and the Beyer M-58, or the Sennheiser K-6 modular system with
capsules of your choice.
Choosing a pattern is largely a question of taste and production style.
Some producers prefer the open sound of an omni, others the closer, tighter
sound of a directional mic. Some use short shotgun mics up close for interviews,
giving a high degree of rejection of extraneous noise.
Avoid the temptation to use lavaliere microphones, at least for interview
recording. Clipped to a lapel, or hanging around the neck, the lav mic is
in a less-than-ideal position for good voice pick-up. Additionally, if the
subject is moving around, clothes and cables will likely add unacceptable
Here’s a comparison of a small number of the more popular and/or affordable
Electrovoice 635N/D (pdf file)Dynamic, Omni, Small diaphragmAll-around workhorse reporter’s mic. Cheap. Can hammer
nails with it. (80hz-13khz)
Electrovoice RE-50 (pdf file)Dynamic, Omni, Small diaphragmSame microphone as the 635A, but with better pop filtering
from handling noise. (80hz-13khz)
Beyer M-58 (pdf file)Dynamic, Omni, Small diaphragmBetter frequency response than above mics
(40hz-20khz), hotter output.
D230Dynamic, Omni, Small diaphragmSimilar to RE-50, but with much wider frequency
SM-58Dynamic, Cardioid, Small diaphragmThe most popular all-purpose vocal mic in the world. Very
rugged, good sound.
Cheap. (about $100)
C-1000Condenser, Cardioid, Small diaphragmGood frequency response (50hz-20khz,) uses standard 9
K6/ME66Condenser, Short shotgun, Small diaphragmModular, can fit different capsule on K6 power supply.
Very tight pattern, good for recording from medium distance.
K6/ME64Condenser, Cardioid, Small diaphragmModular, can fit different capsule on K6 power
K6/ME62Condenser, Omni, Small diaphragmModular, can fit different capsule on K6 power
Neumann 180 seriesCondenser, Small diaphragmOmni, cardioid and hypercardioid mics. Very small.
C-414Condenser, Variable Pattern, Large DiaphragmClassic, versatile large-diaphragm condenser, suited
for studio announce.
C-3000Condenser, Cardioid, Large DiaphragmAffordable large-diaphragm condenser, with sound
similar to AKG 414.
U87Condenser, Variable Pattern, Large DiaphragmTHE big, warm announce mic. Large-diaphragm condenser
Neumann TLM 103Condenser, Cardioid only, Large DiaphragmAffordable Large-diaphragm condenser with Neumann
sound. (About $700)
RE-20 (pdf file)Dynamic, Cardioid, Large DiaphragmPerhaps the most common on-air announce mic. Warm,
flat sound. Good
421Dynamic, Cardioid, Large DiaphragmVersatile mic effective on everything from voice to
Rode NT1Condenser, Cardioid, Large DiaphragmVery inexpensive large-diaphragm condenser (about
$200) Good sound
quality, similar to Sennheiser 421, but louder. (20hz-20khz)
319Condenser, Cardioid, Large DiaphragmAnother very inexpensive large-diaphragm condenser
mic (about $200
in some stores and catalogs) rounder, warmer sound than AKG or Rode.
For more on this topic, join us in the Transom Talk Boards.
For More on Mics
- A summary from the UCSC
electronic music studios.
- DPA microphones’ Microphone
- A Transom discussion on Microphones and MiniDiscs
Up Next: Stereo mics, and stereo techniques with two mics: X-Y,
M-S, ORTF and lots more acronyms decoded and compared.