Convolution brickwall lowpass or highpass filter.

**image 2-Parametres_BrickWall.png**

Sliders under the graph:
\begin{itemize}
\item Cut-off Frequency: cut-off frequency of the lowpass/highpass filter.
\item Bandwidth: Bandwidth of the lowpass/highpass filter.
\item Filter order: Filter order of the lowpass/highpass filter.
\end{itemize}

Dropdown menus and toggles:
\begin{itemize}
\item Label Type: Type of filter (lowpass or highpass **à vérifier --> autres types).
\item Balance: Adjust the signal amplitude by comparing it with a sinusoidal wave with a fixed amplitude (see "compress") or with the amplitude of the source (see "source").
\item # of Polyphony: Number of voices played simultaneously (polyphony); only available at initialization time.
\item Polyphony Spread: Pitch variation between polyphony voices (chorus); only available at initialization time.
\end{itemize}

Graph only parameters:
\begin{itemize}
\item Overall Amplitude: The amplitude curve applied on the total duration of the performance.
\end{itemize}