diff --git a/gst/audiofx/audiofxbaseiirfilter.c b/gst/audiofx/audiofxbaseiirfilter.c
index 50a00da7c3..1ce4d8bc77 100644
--- a/gst/audiofx/audiofxbaseiirfilter.c
+++ b/gst/audiofx/audiofxbaseiirfilter.c
@@ -372,7 +372,11 @@ gst_audio_fx_base_iir_filter_transform_ip (GstBaseTransform * base,
   if (GST_CLOCK_TIME_IS_VALID (stream_time))
     gst_object_sync_values (GST_OBJECT (filter), stream_time);
 
-  g_return_val_if_fail (filter->a != NULL, GST_FLOW_ERROR);
+  if (filter->a == NULL || filter->b == NULL) {
+    g_return_val_if_fail (filter->a != NULL
+        && filter->b != NULL, GST_FLOW_ERROR);
+    return GST_FLOW_ERROR;
+  }
 
   gst_buffer_map (buf, &map, GST_MAP_READWRITE);
   num_samples = map.size / GST_AUDIO_FILTER_BPS (filter);
diff --git a/gst/audiofx/audioiirfilter.c b/gst/audiofx/audioiirfilter.c
index cf3070f155..8f41e43855 100644
--- a/gst/audiofx/audioiirfilter.c
+++ b/gst/audiofx/audioiirfilter.c
@@ -186,7 +186,7 @@ static void
 gst_audio_iir_filter_init (GstAudioIIRFilter * self)
 {
   GValue v = { 0, };
-  GValueArray *a, *b;
+  GValueArray *a;
 
   a = g_value_array_new (1);
 
@@ -195,8 +195,7 @@ gst_audio_iir_filter_init (GstAudioIIRFilter * self)
   g_value_array_append (a, &v);
   g_value_unset (&v);
 
-  b = NULL;
-  gst_audio_iir_filter_update_coefficients (self, a, b);
+  gst_audio_iir_filter_update_coefficients (self, a, a);
 
   g_mutex_init (&self->lock);
 }