diff --git a/src/SongManager.cpp b/src/SongManager.cpp
index 3f4e8947f2..12134ca710 100644
--- a/src/SongManager.cpp
+++ b/src/SongManager.cpp
@@ -349,7 +349,7 @@ void SongManager::AddGroup( RString sDir, RString sGroupDirName, Group* group )
 	// Add the group to its series if the group has one and if the series exists
 	if( group->GetSeries() != "" )
 	{
-		std::unordered_set<Group*>& series = m_mapSeriesToGroup[group->GetSeries()];
+		std::unordered_set<Group*>& series = m_mapSeriesToGroups[group->GetSeries()];
 		series.insert(group);
 	}
 	//m_sSongGroupBackgroundPaths.push_back( sBackgroundPath );
diff --git a/src/SongManager.h b/src/SongManager.h
index a7ac16711d..31f7414f80 100644
--- a/src/SongManager.h
+++ b/src/SongManager.h
@@ -147,8 +147,8 @@ public:
 	void GetPreferredSortSongs( std::vector<Song*> &AddTo ) const;
 	std::map<RString, std::vector<Song*>> GetPreferredSortSongsMap() const { return m_mapPreferredSectionToSongs;};
 	RString SongToPreferredSortSectionName( const Song *pSong ) const;
-	std::map<RString, Group*> GetGroupGroupMap() const { return m_mapNameToGroup;};
-	std::map<RString, std::unordered_set<Group*>> GetSeriesGroupMap() const { return m_mapSeriesToGroup;};
+	std::unordered_map<RString, Group*> GetGroupGroupMap() const { return m_mapNameToGroup;};
+	std::map<RString, std::unordered_set<Group*>> GetSeriesGroupMap() const { return m_mapSeriesToGroups;};
 	Group* GetGroupFromName(  const RString &sGroupName ) const;
 	Group* GetGroup( const Song *pSong ) const;
 	std::vector<RString> GetPreferredSortSectionNames() const;
@@ -250,8 +250,8 @@ protected:
 	std::vector<RString>		m_sSongGroupBannerPaths; // each song group may have a banner associated with it
 	//vector<RString>		m_sSongGroupBackgroundPaths; // each song group may have a background associated with it (very rarely)
 	
-	std::map<RString, Group*> m_mapNameToGroup;
-	std::map<RString, std::unordered_set<Group*>>	m_mapSeriesToGroup;
+	std::unordered_map<RString, Group*> m_mapNameToGroup; // maps a group's name on disk (folder) to a Group object
+	std::map<RString, std::unordered_set<Group*>>	m_mapSeriesToGroups;
 
 	struct Comp { bool operator()(const RString& s, const RString &t) const { return CompareRStringsAsc(s,t); } };
 	typedef std::vector<Song*> SongPointerVector;