| It is with
regret that I often see many users holding their wireless
handheld microphones in various major stage, TV and concert
performances using incorrect techniques. Inappropriate usage
of a premium microphone can not only diminish its original
superb performance characteristics and sound quality, but
can even make it seem no better than an inferior quality
microphone.
Many audio engineers have their own microphone sound preferences
and feel that they can obtain the sound they want by simply
using a leading brandname of microphone coupled with their
own sound adjustments. The importance of mentoring the users
in the art of correctly using a microphone is often sadly
overlooked. A microphone is simply a part of the complete
audio system. A satisfactory sound cannot be achieved, even
when using the most expensive microphones, without a thorough
understanding of the proper usage and adjustment of the
microphone as well as the other related audio components.
The same principle applies in driving an expensive sports
car. If drivers are not fully aware of a car's unique characteristics
and operation, they will be unable to get the maximum performance
out of the car.
Below are a few recommendations to enhance
the sound of a microphone:
1.
Do Not Grab and Cover the Microphone Grille:
Many performers tend to hold the microphone by the grille
( Fig.1A/1B). Unfortunately,
this position seriously degrades both the sound quality
and directionality of a microphone. Even the most expensive
microphone will have its original sound quality compromised
by this method. Grabbing a microphone by the grille will
isolate the capsule's acoustic resonance circuit and/or
change the capsule resonator's frequency. This results in
an inferior performance in both frequency response and the
separation of directionality. In addition, a palm's sound-focusing
effect will tend to strengthen resonances in certain frequencies
and can cause unwanted feedback.
Although a wireless microphone is convenient
and safe to use without those tangling cables, users often
negate their inherent superior characteristics by the use
of improper techniques in holding the microphone. Therefore,
to achieve the best sound possible, a microphone user must
learn the proper techniques, which fortunately are rather
simple. The single most important principal to remember
is to always hold the microphone by its housing or body
instead of covering the microphone grill (Fig.
2).
2.
Do Not Hold Over the Antenna:
Traditional design has protruding antenna
(Fig. 3). Modern design has built-in antenna (Fig.
4) or external design (Fig.
5 & 6). If users hold the microphone over or
near these areas the transmission range will deteriorate
(Fig. 7A/B). The transmission
range will deteriorate severely if holding it with both
hands (Fig. 8A/B).
3.
Do Not Hold Two Microphones in One Hand:
Holding two different frequency transmitters in close proximity
can cause intermodulation interference (Fig.9).
This is especially risky in multi-channel system operations
where issues such as interference and unstable reception
can easily cause the audio quality to deteriorate.
Close proximity causes interference in a microphone's audio
frequency phase and directionality, and can destroy a microphone's
default characteristics, apart from just RF interference.
When both microphones' audio signals are in phase, it adds
up to two microphones' audio output and a subsequent sudden
increase of the amplifier volume, thus causing feedback
(Fig. 10A/B). Conversely, if the signals are out
of phase, they will offset each other's output and result
in insufficient volume (Fig. 11A/B).
When two microphones get close to each other, their directionality
will interfere with each other and destroy their default
directionality. Performance tends to get worse as the distance
between two microphones diminishes. Therefore, users should
avoid the practice of holding two or more microphones simultaneously
in one hand to prevent an undesirable loss in output volume,
frequency response, and directionality. If more microphones
need to be used simultaneously, then keep one microphone
at least 30 cm away from the others to reduce the likelihood
of detrimental changes in performance.
4.
Keep a Proper Distance between the wireless Microphone and
Mouth!
A proper technique is required for
using directional microphones because the distance between
the microphone and your mouth has a significant impact on
sensitivity and performance. There is an inverse relationship
between microphone sensitivity and the distance from the
mouth to the microphone. Consequently, performers with a
"weaker" sound level cannot expect to hold the
microphone too far away from their mouth and compensate
by turning up the amplifier volume to increase the sound
level as this will easily cause feedback. In contrast, performers
with a "louder" sound level should not hold the
microphone too close as this will easily result in causing
the amplifier system to have overload distortion.
Furthermore, a large-diaphragm directional microphone has
a very distinct proximity effect. When the microphone is
close to the mouth, the bass response is strengthened as
the distance gets closer (Fig. 12A).
Therefore, if a performer's sound is insufficient in bass
response, they can hold the microphone closer and use the
proximity effect to help compensate for the lower bass level.
Conversely, if a performer's voice is too heavy in the bass
register, increasing the distance between the microphone
and their mouth will decrease the proximity effect and reduce
the bass response, thus making their voice become clearer
(Fig. 12B).
The distance between the microphone and the mouth also
has a significant effect on "popping noises".
This is especially severe when you are using a microphone
that has high sensitivity and a stronger low-frequency response.
To reduce this problem, one must be very careful to adjust
the microphone to an optimal operating distance and select
a microphone that has excellent "popping" noise
prevention. Most premium and professional microphones have
a highly effective design to eliminate "popping"
noises.
As described above, the sound of two identical microphones
will be significantly affected just by how they are being
held. Practicing a proper holding technique and learning
to use the proximity effect that best suits the performer's
voice should guarantee the most desirable volume and tone
while avoiding annoying "popping" noises. Therefore,
singers that use wireless microphones should strive to get
the best performance possible by learning these techniques
to make the best use of a microphone's performance characteristics.
5.
Avoid Pointing the Wireless Microphone Directly Towards
the Speakers
Most of microphones used in singing applications are directionality
capsules. Hence, holding microphone at the side, or the
rear of speaker has less possibility of feedback effect
(Fig. 13). If standing in front
of speakers is necessary, one must controls the angle between
microphone and speakers under certain degrees to avoid feedback.
Holding microphone vertically or horizontally while it has
90 degrees angle towards speaker can minimized occurrence
of feedback (Fig. 14). When
holding cardioid microphone 180 degrees (Fig.
15) or holding super-cardioid microphone 120~140
degrees ( Fig. 16) towards the
front of speaker has minimum feedback. Understanding directionality
of your own microphone is crucial and helpful in avoiding
loud feedback when nearing or in front of speakers. Therefore,
regardless which famous or premium microphone feedback can
occur if not properly angled or positioned.
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