Marani LPP-480F, Руководство пользователя

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- Smoothing
The smoothing parameters allows limiting the FIR filter action in such a way to “correct” the IR in
its average behaviour. In other words, when the smoothing is enabled, the FIR filter doesn't apply a
punctual IR compensation, but it is limited to correct only an averaged IR response.
Smoothing may slightly degrades the compensation capabilty of the FIR filter in axis (i.e. in the
meausured point), but it generally allows to enlarge the listening area where the IR correction is
effective.
The smoothing can be applied to the magnitude response only or to both magnitude and phase.
For the magnitude smoothing, the algorithm scans the frequency response of the FIR filter
searching for frequency points where the magnitude is above a given threshold Thr [dB], (or below
-Thr [dB]). In those points, a moving average window is applied, with the aim to smooth the
magnitude peaks. This way, choosing a proper threshold value, a selective smoothing can be
applied to the magnitude response.
The averaging window width is a control parameter, by which the user can increase or decrease the
averaging effect.
The picture below shows how the magnitude smoothing works, by comparing the magnitude
response before (left side plot) and after (right side plot) enabling the smoothing.
Setting up the threshold to 0dB, the smoothing is applied to the whole magnitude response, as
shown in the following picture (left side plot, smoothing disabled; right side plot, smoothing
enabled)