According to one embodiment, a sound corrector includes a signal outputter, a response signal, a frequency specifier, a coefficient specifier, a filter, and an outputter. The module further comprises a cover which has a given annular section which closes an annular outlet opening for the gas bag and has a stationary central portion which is surrounded by the annular section. A light detector disposed on the sensor pad is configured to detect near-infrared light generated by the light source. The conference phone can connect with one or more wireless devices through the wireless interface. A noise free spectrum is then reconstructed from the corrected PSD distribution.