Communications Solutions UK Limited
Understanding headsets
Monaural, binaural, and stereo headsets
Headphones usually come in double earpiece design,
whereas headsets can come in single-earpiece and double
earpiece designs. Single earpiece Headsets are known as
monaural headsets. However, double earpiece headsets comes
in both stereo type or binaural type. Stereo refers to two
channels of audio signal, one for each earpiece, and
binaural headsets offer the same audio channel for both
ear-pieces. Headphones are designed mainly for music
listening, so most often they come in stereo version.
Professional users may choose to wear monaural headsets
because they free up the users' other ear, so they can be
more conscious of their work surroundings. Telephone
headsets only come in binaural type for double earpiece
designs because telephone only offers single-channel input
and output, so all double earpiece telephone headsets are
binaural.
However, for computer or other audio applications, where
the sources offer two-channel output, stereo headsets are
the norm. Telephone Headsets generally use 150 Ohm
loudspeakers with a narrower frequency range, so sound
outside the voice band is less audible to reduce background
noise. Stereo computer headsets, on the other hand, use 32 Ω
loudspeakers which have a much broader frequency range, and
is more suitable of music listening.
External microphone vs. microtube
The microphone arm of headsets come in external
microphone type and transparent voicetube type. External
microphone designs have the microphone housed in the front
end of the microphone arm, inside a microphone capsule.
Transparent voicetube designs are also called Internal
Microphone design, meaning the microphone is housed near the
arm-rotation mechanism. The sound from the user travels
through the sealed transparent tube to the hidden
microphone. Voicetube designs look better, and are
considered professional based on pre-set norms; however when
compared with an external microphone design, an external
microphone headset usually has a much better performance.
Voicetube headsets usually only come in the form of
telephone headset or mobile headset, there are not any
computer headsets using voicetube designs and there is no
particular technical reason for this, it is probably purely
the industry norm.
Noise-cancelling microphone vs. omni-directional
microphone
External microphone design also comes in two major types:
omni-directional and noise-cancelling. Noise-cancelling
microphone headsets use bi-directional microphone as
elements. A bi-directional microphone's receptive field is,
as its name suggests, two angles only. In fact, its
receptive field is limited to only the front and the direct
opposite back of the microphone. This will create an "8"
shape field, and this design is the best method for only
picking up sound from a close proximity of the user,
meanwhile not picking up most surrounding noises.
Bi-directional microphone works better than uni-directional
microphone (single angle reception field) because uni-directional
microphone also picks up some of the sound 90-degrees (both
sides) to the desired angle. Omni-directional microphone
picks up the complete 360-degree field, hence it is also the
best receptive microphone but it also picks up most of the
surrounding noises. In some instances, when a higher
sensitivity is required for the microphone, or when the
sound source is further away from the microphone, omni-direction
microphone is the preferred choice. In fact, almost all
voicetube designs employ an omni-directional microphone
(since the sound source needs to travel through the
voicetube before it reaches the microphone). |
