diff --git a/libs/backends/alsa/alsa_audiobackend.h b/libs/backends/alsa/alsa_audiobackend.h
index 48115f9f05..2a2cc94046 100644
--- a/libs/backends/alsa/alsa_audiobackend.h
+++ b/libs/backends/alsa/alsa_audiobackend.h
@@ -409,8 +409,16 @@ class AlsaAudioBackend : public AudioBackend {
 		std::vector<AlsaPort *> _system_midi_in;
 		std::vector<AlsaPort *> _system_midi_out;
 
+		struct SortByPortName
+		{
+			bool operator ()(const AlsaPort* lhs, const AlsaPort* rhs) const
+			{
+				return lhs->name () < rhs->name ();
+			}
+		};
+
 		typedef std::map<std::string, AlsaPort *> PortMap; // fast lookup in _ports
-		typedef std::set<AlsaPort *> PortIndex; // fast lookup in _ports
+		typedef std::set<AlsaPort *, SortByPortName> PortIndex; // fast lookup in _ports
 		PortMap _portmap;
 		PortIndex _ports;
 
diff --git a/libs/backends/coreaudio/coreaudio_backend.h b/libs/backends/coreaudio/coreaudio_backend.h
index 6153b12e10..58e81342c1 100644
--- a/libs/backends/coreaudio/coreaudio_backend.h
+++ b/libs/backends/coreaudio/coreaudio_backend.h
@@ -466,8 +466,16 @@ class CoreAudioBackend : public AudioBackend {
 	std::vector<CoreBackendPort *> _system_midi_in;
 	std::vector<CoreBackendPort *> _system_midi_out;
 
+	struct SortByPortName
+	{
+		bool operator ()(const CoreBackendPort* lhs, const CoreBackendPort* rhs) const
+		{
+			return lhs->name () < rhs->name ();
+		}
+	};
+
 	typedef std::map<std::string, CoreBackendPort *> PortMap; // fast lookup in _ports
-	typedef std::set<CoreBackendPort *> PortIndex; // fast lookup in _ports
+	typedef std::set<CoreBackendPort *, SortByPortName> PortIndex; // fast lookup in _ports
 	PortMap _portmap;
 	PortIndex _ports;
 
diff --git a/libs/backends/dummy/dummy_audiobackend.h b/libs/backends/dummy/dummy_audiobackend.h
index 5caf8bafd9..12abe7be92 100644
--- a/libs/backends/dummy/dummy_audiobackend.h
+++ b/libs/backends/dummy/dummy_audiobackend.h
@@ -451,8 +451,16 @@ class DummyAudioBackend : public AudioBackend {
 		std::vector<DummyMidiPort *> _system_midi_in;
 		std::vector<DummyMidiPort *> _system_midi_out;
 
+		struct SortByPortName
+		{
+			bool operator ()(const DummyPort* lhs, const DummyPort* rhs) const
+			{
+				return lhs->name () < rhs->name ();
+			}
+		};
+
 		typedef std::map<std::string, DummyPort *> PortMap; // fast lookup in _ports
-		typedef std::set<DummyPort *> PortIndex; // fast lookup in _ports
+		typedef std::set<DummyPort *, SortByPortName> PortIndex; // fast lookup in _ports
 		PortMap _portmap;
 		PortIndex _ports;