Add audio filter samples.

LPF20000.txt

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+# version
+v1
+
+# sampling frequency
+# must be multiple of 48000 for best results
+7056000
+
+#base gain
+0.00000774701983513660
+
+#gain scale for X0
+3
+
+#gain scale for X1
+3
+
+#gain scale for X2
+1
+
+#coefficient for Y0
+-2.96438150626551080000
+
+#coefficient for Y1
+2.92939452735121100000
+
+#coefficient for Y2
+-0.96500747158831091000

LPF2000_2tap.txt

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+# version
+v1
+
+# sampling frequency
+# must be multiple of 48000 for best results
+7056000
+
+#base gain
+0.00000316778645516‬
+
+#gain scale for X0
+2
+
+#gain scale for X1
+1
+
+#gain scale for X2
+0
+
+#coefficient for Y0
+-1.9974813602
+
+#coefficient for Y1
+0.9974845280
+
+#coefficient for Y2
+0

LPF2000_3tap.txt

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+# version
+v1
+
+# sampling frequency
+# must be multiple of 48000 for best results
+1764000
+
+#base gain
+0.00000035895956448‬
+
+#gain scale for X0
+3
+
+#gain scale for X1
+3
+
+#gain scale for X2
+1
+
+#coefficient for Y0
+-2.9857524444
+
+#coefficient for Y1
+2.9716062045
+
+#coefficient for Y2
+-0.9858534011