lss = 
  labeledSignalSet with properties:

             Source: {2x1 cell}
         NumMembers: 2
    TimeInformation: "sampleRate"
         SampleRate: 4000
             Labels: [2x3 table]
        Description: "Characterize wave song regions"

 Use labelDefinitionsHierarchy to see a list of labels and sublabels.
 Use setLabelValue to add data to the set.

newlss = 
  labeledSignalSet with properties:

             Source: {2x1 cell}
         NumMembers: 2
    TimeInformation: "sampleRate"
         SampleRate: 4000
             Labels: [2x3 table]
        Description: "Characterize wave song regions"

 Use labelDefinitionsHierarchy to see a list of labels and sublabels.
 Use setLabelValue to add data to the set.

lssconcat = 
  labeledSignalSet with properties:

             Source: {4x1 cell}
         NumMembers: 4
    TimeInformation: "sampleRate"
         SampleRate: 4000
             Labels: [4x3 table]
        Description: "Characterize wave song regions"

 Use labelDefinitionsHierarchy to see a list of labels and sublabels.
 Use setLabelValue to add data to the set.