| -10 dB
Pad switch |
 The
-10 dB Pad switch is a useful tool that decreases the microphone's signal
level of about 10 dB. Thus, overdrive of the signal is prevented for loud
sound sources. The maximal sound pressure level (max. SPL)
is increased of about 10 dB with this function. |
| |
|
| 8 |
 Figure
8 is a typical polar pattern
of studio microphones. Sound sources are recorded in front and behind
the microphone. Thus, this polar pattern is suitable for stage recording,
room acoustics and for recording of two opposite sound sources (e. g. two
voices). |
| |
|
| Cardioid |
 Cardioid
is the most common polar pattern in studios. Sound sources are
recognized kidney-shaped in front of the microphone. Sound sources behind
and sideways of the microphones are reduced. Consequently, this polar pattern
is the best choice for the recording of single sound sources, such as
voice, singing or music instruments. Background noise and feedbacks are
reduced. |
| |
|
| Condenser microphone |
Basically, there are two major types of microphones:
Dynamic and condenser microphones. While dynamic microphones are very robust
and resistant against overmodulation, their sound quality is lower than
the sound quality of condenser microphones. Consequently, dynamic microphone
have no importance for the recording of voice or singing in studios. Condenser
microphones are the best choice for professional studio recording.
 The
condenser unit consists of a metal-plated membrane and a punched metal
plate. The condenser's capacity is build by application of electricity
to membrane and metal plate. This electricity is called phantompower.
The membrane is able to shift in the direction of the sound source and,
consequently, the condenser's capacity is altered resulting in an electric
signal. There are two types of condenser microphones: "True"
and "back-electret" condenser microphones. The back-electret condenser consists
of a precharged condenser unit. Consequently, only a low electricity (e.
g. a battery) is required to use this kind of microphone. However, the
membrane of a back-electret microphone is significantly smaller than the
membrane of a "true" condenser caused by the smaller electricity.
"True" condenser microphone are preferred in studio recording.
|
| |
|
| Equivalent Noise Level |
The equivalent noise level describes the microphone's self noise. Every component of the microphone creates a low self
noise. No microphone is free of selfnoise! The equivalent noise level describes
the sound level that is needed to exceed the self noise. The sound level
of a normal voice is about 60 dB and the sound level of susurration is about
30 dB. Consequently, an equivalent noise level inferior than 30 dB is considered
to be excellent. |
| |
|
| Figure 8 |
see 8 |
| |
|
Frequency
Frequence response |
The frequency response describes the frequency range
that is noticed by the microphone. The human being can notice a frequency
range of 20 - 20000 Hz depending on his age. Consequently, most microphones
are sensitive in this frequency range. |
| |
|
| Impedance |
The impedance describes the microphone's opposition
against the electricity. Usually, an impedance inferior than 600 ohms gives
the best sound result. To maintain the microphone's performance, the impedance
of the recording device should be equal or larger than the microphone's
impedance. |
| |
|
| Low-Cut switch |
The
low-cut switch is a tool that cuts of the lower frequency range (usually
frequences lower than 100 Hz). This frequency range is usually uninteresting
for the recording of voice or singing. However, some noise sources, such
as subsonic noise, are in this frequency range. Those noise sources are
reduced by activation of the low-cut function. Microphones have either an
external or an internal low-cut switch. While the external switch is placed
on the outside of the microphone, the microphone have to be unscrewed for
activation of the internal low-cut switch. |
| |
|
| max. SPL |
The maximal sound pressure level describes the microphone's
maximal sound load. The max. SPL is typically labeled for a specific frequence
(e. g. 1000 Hz). The microphone starts to distort if exceeding this threshold.
A parameter for the distortion is the total harmonic distortion (THD).
A max. SPL of 130 dB @ 1000 Hz with a THD of 1% means that the microphone's
signal is distorted to 1% if the sound pressure level exceeds 130 dB at
a frequence of 1000 Hz. |
| |
|
| Membrane |
The
membrane is one of the main items in a condenser
microphone. It is the central unit for sound cognition. The
membrane can shift in the direction of a sound source resulting in an altered
capacity of the microphone's condernser unit. The membrane is gold-plated
in high-grade microphones resulting in a better conductibility. Ultra-thin
membranes (about 3 µm) are best-known for a great sound performance.
You will find further information at the keyword condenser
microphones. |
| |
|
| Microphone preamp |
A microphone preamp is needed to amplify the microphone's
signal. Microphones don't have an integrated preamp (except USB microphones). Consequently, the output
signal of a microphone is low and a microphone preamplification is needed.
Most mixers or soundcards are equipped with a microphone preamp. However,
the amplification of common computer soundcards is not sufficient
to generade an acceptable amplification. The purchasing of a suitable preamp
is necessary in this case. The preamp should be connected to the
LINE IN input of your recording device! Don't mix up preamps and phantompower
supplies! |
| |
|
| Omnidirectional |
 Omnidirectional
is a typical polar pattern for studio microphones. The
microphone is able to notice sound sources from every direction. Consequently,
this polar pattern is suitable for stage recording, recording of room acoustics,
of large sound sources (e. g. choir, orchestra) or for scattered sound sources
around the microphone. |
| |
|
| Phantompower |
The phantompower is a voltage of 48V. This voltage is
needed to charge the studio microphone's condenser unit. Condenser
microphones don't work without a phantompower! Back-electred
condenser microphones consist of a precharged condenser unit. Consequently,
the needed phantompower is reduced and can be provided by a simple battery.
However, those microphones are equipped with a smaller membrane and, therefore,
are discriminated in contrast to "true" condenser microphones.
Don't mix up phantompower supplies with microphone
preamps! |
| |
|
| Polar pattern |
The polar pattern describes the directions from where
the microphone is sensitive for sound waves. The choice of the correct polar
pattern is critical for the disturbance by other sound sources (such as
background noise) and for the occurrence of feedback. The best choice for
the recording of single sound sources (such as voice or singing) with reduced
background noise and feedbacks are cardioid
or super-cardioid polar patterns.
Omnidirectional or
8 polar patterns are suitable
for several or huge sound sources, stage recordings, room acoustics or scattered
sound sources. |
| |
|
| Preamp |
see Microphone preamp |
| |
|
| Selfnoise |
see Equivalent Noise
Level |
| |
|
| Sensitivity |
 The
microphone's sensitivity describes the sensitivity in terms of the sound
source. A high sensitivity needs only a low preamplification and, consequently,
the noise level is lower. The plot of the microphone's sensitivity against
the frequency response gives relevant information about the microphone's
sound. |
| |
|
| Shockmount |
 The
shockmount is the most important microphone holder system for studio microphones.
The significant advantage in comparision to a simple microphone holder is
that the microphone is laxly fixed within the shockmount. The shockmount
itselfes consists of two units that are suspended with rubber straps. Every
kind of tremor is cleared by this kind of fixation and noise is prevented.
Shockmounts are the most common and preferred microphone holders in studios. |
| |
|
| S/N Ratio |
Die S/N ratio is the abbreviation of signal-noise-ratio.
This parameter describes the difference between the microphone's self noise
and the sound signal. Generally, a bigger S/N ratio means a smaller noise
on the recorded track. |
| |
|
| SPL |
see max. SPL |
| |
|
| Super cardioid |
 Super-Cardioid
is a common polar pattern of studio microphones. Sound
sources are recognized kidney-shaped in front of the microphone. Sound sources
behind and sideways of the microphone are reduced. Consequently, this polar
pattern is the best choice for the recording of single sound sources,
such as voice, singing or music instruments. Background noise and feedbacks
are reduced. |
| |
|
| THD |
The total harmonic distortion describes the harmonic
distortion of a microphone. Distortions are undesired frequences that lead
to a falsified sound result. The THD is an important parameter for the microphone's
maximal sound pressure level (max. SPL).
In this connection, the distortion may not exceed a specific threshold (e.
g. 1%) based on the applied sound pressure level . |
| |
|
Tube
(Tube preamp,
tube microphone) |
 Strictly
speaking, the tube is the out-dated precursor of the current transistor
technology. Tube and transistor play a central role in the amplification
of sound signals. The transistor is smaller, lighter, more robust and more
durable in contrast to the tube. Consequently, most current devices are
equipped with transistor technology. However, tubes are still in vogue for
some applications caused by their warm and soft sound. The quality of tube
amplification is not lower compared to the transistor amplification but
advantages are a matter of taste. Tube microphones are very expensive caused
by their complex technology and low sales. Therefore, the investment into
a tube microphone is not worthwhile for most applications. On the other
hand, the price for a tube preamp is not really different to a transistor
preamp caused by their huge distribution. |
| |
|
