Figure 8
Power spectral densities of various input and output signals, demonstrating a roughly 30 dB echo attenuation. Green: white noise with a nominal 100 mV RMS amplitude played through the loudspeaker. Blue: raw microphone signal (Mic) with 3 dB lower amplitude. Red: the LMS filtered microphone signal (MicSep) with a roughly 30 dB reduced spectral density, close to the density of silence (black). The effect of the 500 Hz–8 kHz band-pass filter is visible by the cutoff. The legend indicates the overall RMS values and the corresponding sound pressure levels in dB re 20 µPa (unweighted).
