diff --git a/webapp/path_navigator.html b/webapp/path_navigator.html
index 373bd16..e499cff 100644
--- a/webapp/path_navigator.html
+++ b/webapp/path_navigator.html
@@ -35,15 +35,17 @@
 
         const state = new Map();
         nodes.forEach(n => {
-          const chordLabel = n.data('chordLabel');
-          const bounds = opts.bounds[chordLabel] || { min: 0, max: graphWidth };
-          state.set(n.id(), {
-            x: n.position('x'),
-            y: n.position('y'),
-            vx: 0,
-            fx: 0,
-            bounds: bounds,
-          });
+            if (n.data('isLabel')) return;  // Skip label nodes
+          
+            const chordLabel = n.data('chordLabel');
+            const bounds = opts.bounds[chordLabel] || { min: 0, max: graphWidth };
+            state.set(n.id(), {
+              x: n.position('x'),
+              y: n.position('y'),
+              vx: 0,
+              fx: 0,
+              bounds: bounds,
+            });
         });
 
         const edgeList = edges.map(e => ({ 
@@ -330,6 +332,32 @@
             return parseFloat(fracStr);
         }
         
+        // Play all nodes in a chord on the siren
+        function playChordOnSiren(chordIdx) {
+            // Find all nodes in this chord (exclude label nodes)
+            const nodes = cy.nodes().filter(n => 
+                n.data('chordIndex') === chordIdx && !n.data('isLabel')
+            );
+            
+            // Clear old sirenActive markers
+            cy.nodes().forEach(n => n.data('sirenActive', ''));
+            
+            // Play each node using chordIndex + localId (let server calculate frequency)
+            nodes.forEach((node) => {
+                const localId = node.data('localId');
+                
+                fetch('/api/play-siren', {
+                    method: 'POST',
+                    headers: {'Content-Type': 'application/json'},
+                    body: JSON.stringify({ 
+                        chordIndex: chordIdx, 
+                        nodeIndex: localId
+                    })
+                });
+                node.data('sirenActive', 'true');
+            });
+        }
+        
         // Toggle between cents and frequency display
         function toggleDisplayUnit() {
             displayMode = displayMode === 'cents' ? 'frequency' : 'cents';
@@ -386,7 +414,7 @@
                 container: document.getElementById('graph-container'),
                 style: [
                     {
-                        selector: 'node',
+                        selector: 'node[color]',
                         style: {
                             'background-color': 'data(color)',
                             'width': 32,
@@ -402,6 +430,22 @@
                             'border-width': 0,
                         }
                     },
+                    {
+                        selector: 'node[isLabel = "true"]',
+                        style: {
+                            'background-color': '#888888',
+                            'width': 40,
+                            'height': 40,
+                            'label': 'data(chordIndex)',
+                            'color': '#ffffff',
+                            'font-size': '18px',
+                            'font-weight': 'bold',
+                            'text-valign': 'center',
+                            'text-halign': 'center',
+                            'text-outline-width': 0,
+                            'border-width': 0,
+                        }
+                    },
                     {
                         selector: 'node[sirenActive = "true"]',
                         style: {
@@ -501,6 +545,13 @@
                     return;
                 }
                 
+                // Handle label node clicks
+                if (node.data('isLabel')) {
+                    const chordIdx = node.data('chordIndex');
+                    playChordOnSiren(chordIdx);
+                    return;
+                }
+                
                 const chordIndex = node.data('chordIndex');
                 const localId = node.data('localId');
                 
@@ -598,10 +649,11 @@
             allGraphsData.graphs.forEach((graph, chordIdx) => {
                 if (!graph || !graph.nodes) return;
                 
-                const nodes = graph.nodes;
-                const edges = graph.edges || [];
-                const xBase = 100 + chordIdx * chordSpacing;
-                const idMap = {};
+            const nodes = graph.nodes;
+            const edges = graph.edges || [];
+            const gap = 50;
+            const xBase = 100 + chordIdx * (chordSpacing + gap);
+            const idMap = {};
                 
                 // Create unique IDs per chord to avoid collisions
                 const chordPrefix = `c${chordIdx}_`;
@@ -641,6 +693,18 @@
                         },
                     });
                 });
+                
+                // Add label node for this chord (locked so layout doesn't move it)
+                elements.push({
+                    group: 'nodes',
+                    data: {
+                        id: `label_${chordIdx}`,
+                        chordIndex: chordIdx,
+                        isLabel: "true",
+                    },
+                    position: { x: xBase + (chordSpacing * 0.15), y: 30 },
+                    locked: true,
+                });
             });
             
             if (elements.length === 0) return;
diff --git a/webapp/server.py b/webapp/server.py
index 6226889..bd1a7cc 100644
--- a/webapp/server.py
+++ b/webapp/server.py
@@ -129,20 +129,37 @@ def play_freq():
 def play_siren():
     """Play a single frequency for a node on the siren."""
     data = request.json
+
+    # Support two modes:
+    # 1. chordIndex + nodeIndex (from clicking a single node)
+    # 2. frequency + voice (from clicking a chord label)
     chord_index = data.get("chordIndex")
     node_index = data.get("nodeIndex")
+    frequency = data.get("frequency")
+    voice = data.get("voice")
 
-    if chord_index < 0 or chord_index >= len(chords):
-        return jsonify({"error": "Invalid chord index"}), 400
+    if frequency is None and voice is None:
+        # Mode 1: use chordIndex/nodeIndex
+        if chord_index is None or node_index is None:
+            return jsonify(
+                {"error": "Missing chordIndex/nodeIndex or frequency/voice"}
+            ), 400
 
-    chord = chords[chord_index]
-    if node_index < 0 or node_index >= len(chord):
-        return jsonify({"error": "Invalid node index"}), 400
+        if chord_index < 0 or chord_index >= len(chords):
+            return jsonify({"error": "Invalid chord index"}), 400
 
-    pitch = chord[node_index]
-    fraction = Fraction(pitch.get("fraction", "1"))
-    frequency = fundamental * float(fraction)
-    voice = node_index + 1  # 1-indexed
+        chord = chords[chord_index]
+        if node_index < 0 or node_index >= len(chord):
+            return jsonify({"error": "Invalid node index"}), 400
+
+        pitch = chord[node_index]
+        fraction = Fraction(pitch.get("fraction", "1"))
+        frequency = fundamental * float(fraction)
+        voice = node_index + 1  # 1-indexed
+    else:
+        # Mode 2: use provided frequency/voice
+        if frequency is None or voice is None:
+            return jsonify({"error": "Missing frequency or voice"}), 400
 
     # Send to siren (192.168.4.200:54001) using current fundamental
     siren_sender = OSCSender(ip="192.168.4.200", port=54001, fundamental=fundamental)
@@ -153,8 +170,6 @@ def play_siren():
         {
             "frequency": frequency,
             "voice": voice,
-            "fundamental": fundamental,
-            "fraction": pitch.get("fraction", "1"),
             "destination": "siren",
         }
     )