Synchronous Average
This module retrieves the system's impulse response(s) from a recording made after excitation with the signal generated through the Generate Sweep module. For example, here is presented the case of a the measurement of a two-loudspeaker system in front of a stereo microphone, in which a repetition of 3 sweeps is played first on the left channel, then on the right channel, and the two microphonic channels are simultaneously sampled.
This processing is suitable only for measurement made with synchronous playback and recording, typically made under CoolEditPro in Multitrack mode, playing the excitation signal on track 1 and simultaneously recording the binaural response on track 2, as shown here:
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The deconvolution is made, in this case, simply convolving the recorded response (track 2) with the clipboard, where the proper inverse filter was already stored from the Generate Sweep module. This way, the following sequence of raw impulse responses is obtained:
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At this point, we want to average together the responses to the three repetitions of each signal, while maintaining separated the response of the left and right loudspeaker. Furthermore, we want to keep only the first 4096 points of each response. All this is done with the Synchronous Average module, setting properly its parameters as shown here:
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After the averaging, a set of 4 impulse response is obtained. First are the binaural IR of the Left loudspeaker, followed by the binaural IR of the Right loudspeaker:
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The impulse response files, in this format called 2x2, are already suitable for the calculation of cross-talk canceling filters through the Inverse Kirkeby module.