diff --git a/audio/filters/IIR.dsp b/audio/filters/IIR.dsp
index fa45b8ce6b..bfeecb2a0f 100644
--- a/audio/filters/IIR.dsp
+++ b/audio/filters/IIR.dsp
@@ -1,8 +1,23 @@
 filters = 1
 filter0 = iir
 
-iir_frequency = 1024.0
-iir_quality = 0.707
-iir_gain = 0.0
-iir_type = LPF
+# Defaults.
+#iir_frequency = 1024.0
+#iir_quality = 0.707
+#iir_gain = 0.0
+#iir_type = LPF
+
+# Filter types:
+# LPF: Low-pass
+# HPF: High-pass
+# BPCSGF: Band-pass #1
+# BPZPGF: Band-pass #2
+# APF: Allpass
+# NOTCH: Notch filter
+# RIAA_phono: RIAA record/tape deemphasis
+# PEQ: peaking band EQ
+# BBOOST: Bassboost
+# LSH: Low-shelf
+# HSH: High-shelf
+# RIAA_CD: CD de-emphasis
 
diff --git a/audio/filters/iir.c b/audio/filters/iir.c
index 3ad58c7010..8347ecc6f3 100644
--- a/audio/filters/iir.c
+++ b/audio/filters/iir.c
@@ -57,7 +57,6 @@ static void iir_free(void *data)
    free(data);
 }
 
-
 static void iir_process(void *data, struct dspfilter_output *output,
       const struct dspfilter_input *input)
 {