With the constant enlargement of the internet bandwidth, the internet
video conference has become possible. However, the wide bandwidth
does not mean high quality of sound. The consumers usually need
to wear the earphones to get the clear sound effects, and it is
really inconvenient for them. Therefore, VISTA has already started
to support the function of microphone array, which help to record
sound more clearly, and can eliminate the noise and wind shear sound
in the background.
Naturally, besides the support of the operating system, the computer
hardware also needs to be matched. Consequently, with the collocation
of the microphone array and the DSP, the consumers can easily enjoy
using the web phone such as SKYPE without wearing the headsets.
The theory of the microphone array is to set more than two pieces
of microphones to record the sound separately, and than the DSP
will pick the tonic we want. The simplest design is to pair a unidirectional
microphone and an Omni directional one, which can limit the sound
receiving range at the width of 120-140 degrees in front of the
microphone, and then the SPL will be reduced over 20dB beyond this
conical area. This is the reason why the ambient noises can be reduced
widely and hardly to be heard.