diff --git a/libs/ardour/ardour/chan_mapping.h b/libs/ardour/ardour/chan_mapping.h
index 7b9f81976d..baa3e9f6a9 100644
--- a/libs/ardour/ardour/chan_mapping.h
+++ b/libs/ardour/ardour/chan_mapping.h
@@ -38,6 +38,7 @@ class LIBARDOUR_API ChanMapping {
 public:
 	ChanMapping() {}
 	ChanMapping(ARDOUR::ChanCount identity);
+	ChanMapping(const ChanMapping&);
 
 	uint32_t get(DataType t, uint32_t from, bool* valid);
 	uint32_t get(DataType t, uint32_t from) { return get (t, from, NULL); }
diff --git a/libs/ardour/ardour/plugin_insert.h b/libs/ardour/ardour/plugin_insert.h
index ffa55b9eaa..ed97126e34 100644
--- a/libs/ardour/ardour/plugin_insert.h
+++ b/libs/ardour/ardour/plugin_insert.h
@@ -27,6 +27,7 @@
 
 #include "ardour/ardour.h"
 #include "ardour/libardour_visibility.h"
+#include "ardour/chan_mapping.h"
 #include "ardour/types.h"
 #include "ardour/parameter_descriptor.h"
 #include "ardour/processor.h"
@@ -204,6 +205,8 @@ class LIBARDOUR_API PluginInsert : public Processor
 
 	/** details of the match currently being used */
 	Match _match;
+	ARDOUR::ChanMapping _in_map;
+	ARDOUR::ChanMapping _out_map;
 
 	void automation_run (BufferSet& bufs, framepos_t start, pframes_t nframes);
 	void connect_and_run (BufferSet& bufs, pframes_t nframes, framecnt_t offset, bool with_auto, framepos_t now = 0);
diff --git a/libs/ardour/chan_mapping.cc b/libs/ardour/chan_mapping.cc
index 57734803d2..83ded4141c 100644
--- a/libs/ardour/chan_mapping.cc
+++ b/libs/ardour/chan_mapping.cc
@@ -40,6 +40,11 @@ ChanMapping::ChanMapping(ChanCount identity)
 	}
 }
 
+ChanMapping::ChanMapping (const ChanMapping& other )
+	: _mappings (other._mappings)
+{
+}
+
 uint32_t
 ChanMapping::get(DataType t, uint32_t from, bool* valid)
 {
diff --git a/libs/ardour/plugin_insert.cc b/libs/ardour/plugin_insert.cc
index c085f1f9cb..19571c6b5f 100644
--- a/libs/ardour/plugin_insert.cc
+++ b/libs/ardour/plugin_insert.cc
@@ -369,19 +369,16 @@ PluginInsert::connect_and_run (BufferSet& bufs, pframes_t nframes, framecnt_t of
 	ChanCount const in_streams = input_streams ();
 	ChanCount const out_streams = output_streams ();
 
-	ChanMapping in_map (in_streams);
-	ChanMapping out_map (out_streams);
 	bool valid;
 	if (_match.method == Split) {
 		/* fix the input mapping so that we have maps for each of the plugin's inputs */
-		in_map = ChanMapping (natural_input_streams ());
 
 		/* copy the first stream's buffer contents to the others */
 		/* XXX: audio only */
-		uint32_t first_idx = in_map.get (DataType::AUDIO, 0, &valid);
+		uint32_t first_idx = _in_map.get (DataType::AUDIO, 0, &valid);
 		if (valid) {
 			for (uint32_t i = in_streams.n_audio(); i < natural_input_streams().n_audio(); ++i) {
-				bufs.get_audio(in_map.get (DataType::AUDIO, i, &valid)).read_from(bufs.get_audio(first_idx), nframes, offset, offset);
+				bufs.get_audio(_in_map.get (DataType::AUDIO, i, &valid)).read_from(bufs.get_audio(first_idx), nframes, offset, offset);
 			}
 		}
 	}
@@ -441,6 +438,12 @@ PluginInsert::connect_and_run (BufferSet& bufs, pframes_t nframes, framecnt_t of
 
 	}
 
+
+	// copy - for now - since the map is offset below
+	// TODO: use dedicated maps per plugin
+	ChanMapping in_map (_in_map);
+	ChanMapping out_map (_out_map);
+
 	for (Plugins::iterator i = _plugins.begin(); i != _plugins.end(); ++i) {
 		if ((*i)->connect_and_run(bufs, in_map, out_map, nframes, offset)) {
 			deactivate ();
@@ -486,16 +489,8 @@ PluginInsert::silence (framecnt_t nframes)
 		return;
 	}
 
-	ChanMapping in_map(input_streams());
-	ChanMapping out_map(output_streams());
-
-	if (_match.method == Split) {
-		/* fix the input mapping so that we have maps for each of the plugin's inputs */
-		in_map = ChanMapping (natural_input_streams ());
-	}
-
 	for (Plugins::iterator i = _plugins.begin(); i != _plugins.end(); ++i) {
-		(*i)->connect_and_run (_session.get_scratch_buffers ((*i)->get_info()->n_inputs, true), in_map, out_map, nframes, 0);
+		(*i)->connect_and_run (_session.get_scratch_buffers ((*i)->get_info()->n_inputs, true), _in_map, _out_map, nframes, 0);
 	}
 }
 
@@ -752,6 +747,22 @@ PluginInsert::configure_io (ChanCount in, ChanCount out)
 		break;
 	}
 
+	if (_match.method == Split) {
+		/* fix the input mapping so that we have maps for each of the plugin's inputs */
+		_in_map = ChanMapping (natural_input_streams ());
+	} else {
+		_in_map = ChanMapping (input_streams ());
+	}
+	_out_map = ChanMapping (output_streams());
+
+#if 0
+	cout << "Set Channel Maps:" << name () << " " << this
+		<< "\nin:\n" << _in_map
+		<< "\nout:\n" << _out_map
+		<< "\n";
+#endif
+
+
 	if (  (old_match.method != _match.method && (old_match.method == Split || _match.method == Split))
 			|| old_in != in
 			|| old_out != out