Figure 2
From: Head tracking extends local active control of broadband sound to higher frequencies
Power spectral density of the signal measured at the microphones in the left and right hand side of the dummy head when it was in the nominal position and the primary source was behind the headrest before control, solid line, after control using the monitoring microphones and observation filter to estimate the signal at the ear position using the remote microphone technique, dashed line, and, for reference, when the microphones in the dummy head themselves were used as the error signals in the control algorithm, dot-dashed line (a) and (b). The results are also shown when the primary source was positioned in front of the headrest in the two lower graphs, (c) and (d), which illustrate the effect of the standard remote microphone technique, RMT, and when it includes a modelling delay of 0.7 ms.
