diff --git a/src/osc_sender.py b/src/osc_sender.py
index 5b7676a..9297a5d 100644
--- a/src/osc_sender.py
+++ b/src/osc_sender.py
@@ -5,6 +5,7 @@ OSC Sender - send chord frequencies via OSC for real-time playback.
 
 import json
 import sys
+import threading
 from pathlib import Path
 
 try:
@@ -15,6 +16,15 @@ except ImportError:
     sys.exit(1)
 
 
+# Module-level flag to cancel any running ramp
+_ramp_cancelled = threading.Event()
+
+
+def cancel_ramp():
+    """Cancel any currently running ramp."""
+    _ramp_cancelled.set()
+
+
 class OSCSender:
     """Send chord frequencies via OSC."""
 
@@ -114,6 +124,51 @@ class OSCSender:
             f"  [Sent kill {'soft' if soft else 'hard'} ({kill_freq}) to {self.num_voices} voices]"
         )
 
+    def ramp_to_chord(self, frequencies, duration_ms=3000, start_freq=20):
+        """Ramp each voice from start_freq to target frequency(s) linearly.
+
+        Args:
+            frequencies: single frequency (int/float) or list of frequencies
+            duration_ms: duration in milliseconds
+            start_freq: starting frequency (single or per-voice list)
+        """
+        import threading
+        import time
+
+        # Handle single frequency vs list
+        if isinstance(frequencies, (int, float)):
+            frequencies = [frequencies]
+
+        # Handle single start_freq vs list (per-voice)
+        if isinstance(start_freq, (int, float)):
+            start_freq = [start_freq] * len(frequencies)
+
+        # Fixed interval time for smooth ramp regardless of duration
+        step_interval = 0.02  # 20ms = 50 Hz update rate
+        num_steps = max(1, int(duration_ms / 1000 / step_interval))
+
+        def run_ramp():
+            _ramp_cancelled.clear()  # Reset cancellation flag
+            for step in range(num_steps + 1):
+                if _ramp_cancelled.is_set():
+                    print("  [Ramp cancelled]")
+                    break
+                progress = step / num_steps
+                for voice_idx, target_freq in enumerate(frequencies):
+                    voice_start = start_freq[voice_idx]
+                    current_freq = voice_start + (target_freq - voice_start) * progress
+                    self.send_single(current_freq, voice_idx + 1)
+                time.sleep(step_interval)
+            else:
+                # Send final exact target frequencies (only if not cancelled)
+                for voice_idx, target_freq in enumerate(frequencies):
+                    self.send_single(target_freq, voice_idx + 1)
+
+        thread = threading.Thread(target=run_ramp)
+        thread.daemon = True
+        thread.start()
+        print(f"  [Started ramp to {len(frequencies)} voices over {duration_ms}ms]")
+
     def send_current(self):
         """Send all voices at their current positions."""
         for voice_idx in range(self.num_voices):
diff --git a/webapp/path_navigator.html b/webapp/path_navigator.html
index e499cff..1ee4e45 100644
--- a/webapp/path_navigator.html
+++ b/webapp/path_navigator.html
@@ -285,6 +285,10 @@
             <input type="number" id="fundamentalInput" value="110" style="width: 60px;">
             <span style="margin-left: 15px;">Octave:</span>
             <input type="number" id="octaveInput" value="2" style="width: 40px;">
+            <span style="margin-left: 15px;">Ramp (s):</span>
+            <input type="number" id="rampDuration" value="3" step="0.1" style="width: 60px;">
+            <span style="margin-left: 15px;">Siren IP:</span>
+            <input type="text" id="sirenIp" value="192.168.4.200" style="width: 100px;">
             <button id="toggleUnitBtn" style="margin-left: 15px;">Show: Cents</button>
         </div>
         
@@ -334,6 +338,8 @@
         
         // Play all nodes in a chord on the siren
         function playChordOnSiren(chordIdx) {
+            const sirenIp = document.getElementById('sirenIp').value || "192.168.4.200";
+            
             // Find all nodes in this chord (exclude label nodes)
             const nodes = cy.nodes().filter(n => 
                 n.data('chordIndex') === chordIdx && !n.data('isLabel')
@@ -351,13 +357,60 @@
                     headers: {'Content-Type': 'application/json'},
                     body: JSON.stringify({ 
                         chordIndex: chordIdx, 
-                        nodeIndex: localId
+                        nodeIndex: localId,
+                        ip: sirenIp
                     })
                 });
                 node.data('sirenActive', 'true');
             });
         }
         
+        // Ramp to a chord or single node on the siren
+        function rampToChord(chordIdx, nodeIdx = null) {
+            const durationSeconds = parseFloat(document.getElementById('rampDuration').value) || 3;
+            const durationMs = durationSeconds * 1000;
+            const startFreq = 20;  // Default start frequency
+            const sirenIp = document.getElementById('sirenIp').value || "192.168.4.200";
+            
+            // Find nodes in this chord (exclude label nodes)
+            const nodes = cy.nodes().filter(n => 
+                n.data('chordIndex') === chordIdx && !n.data('isLabel')
+            );
+            
+            // If nodeIdx is provided, clear only same-color nodes; otherwise clear all
+            if (nodeIdx !== null) {
+                const targetNode = nodes.find(n => n.data('localId') === nodeIdx);
+                if (targetNode) {
+                    const nodeColor = targetNode.data('color');
+                    cy.nodes().forEach(n => {
+                        if (n.data('color') === nodeColor && n.data('sirenActive')) {
+                            n.data('sirenActive', '');
+                        }
+                    });
+                    targetNode.data('sirenActive', 'true');
+                }
+            } else {
+                cy.nodes().forEach(n => n.data('sirenActive', ''));
+                nodes.forEach(node => node.data('sirenActive', 'true'));
+            }
+            
+            fetch('/api/ramp-to-chord', {
+                method: 'POST',
+                headers: {'Content-Type': 'application/json'},
+                body: JSON.stringify({
+                    chordIndex: chordIdx,
+                    nodeIndex: nodeIdx,
+                    duration: durationMs,
+                    startFreq: startFreq,
+                    ip: sirenIp
+                })
+            }).then(r => r.json()).then(data => {
+                console.log('Ramping:', data);
+            }).catch(err => {
+                console.log('Error ramping:', err);
+            });
+        }
+        
         // Toggle between cents and frequency display
         function toggleDisplayUnit() {
             displayMode = displayMode === 'cents' ? 'frequency' : 'cents';
@@ -545,20 +598,34 @@
                     return;
                 }
                 
+                // Check modifiers
+                const isShift = evt.originalEvent && evt.originalEvent.shiftKey;
+                const isRamp = evt.originalEvent && evt.originalEvent.ctrlKey;
+                
                 // Handle label node clicks
                 if (node.data('isLabel')) {
                     const chordIdx = node.data('chordIndex');
-                    playChordOnSiren(chordIdx);
+                    if (isRamp) {
+                        rampToChord(chordIdx);
+                    } else {
+                        playChordOnSiren(chordIdx);
+                    }
                     return;
                 }
                 
                 const chordIndex = node.data('chordIndex');
                 const localId = node.data('localId');
                 
+                // Handle ramp modifier
+                if (isRamp) {
+                    rampToChord(chordIndex, localId);
+                    return;
+                }
+                
                 // Check if Shift key is held - send to siren, otherwise send to SuperCollider
-                const isShift = evt.originalEvent && evt.originalEvent.shiftKey;
                 const endpoint = isShift ? '/api/play-siren' : '/api/play-freq';
                 const destination = isShift ? 'siren' : 'SuperCollider';
+                const sirenIp = document.getElementById('sirenIp').value || "192.168.4.200";
                 
                 console.log('Sending play request to', destination, ':', chordIndex, localId);
                 
@@ -568,7 +635,8 @@
                     body: JSON.stringify({
                         chordIndex: chordIndex,
                         nodeIndex: localId,
-                        octave: parseInt(document.getElementById('octaveInput').value) || 0
+                        octave: parseInt(document.getElementById('octaveInput').value) || 0,
+                        ip: sirenIp
                     })
                 }).then(r => r.json()).then(data => {
                     console.log('Playing on', destination + ':', data.frequency.toFixed(2), 'Hz on voice', data.voice);
@@ -1111,10 +1179,11 @@
                 }
             } else if (e.key === "k") {
                 // Soft kill - send 20 Hz to stop voices gently
+                const sirenIp = document.getElementById('sirenIp').value || "192.168.4.200";
                 fetch('/api/kill-siren', {
                     method: 'POST',
                     headers: {'Content-Type': 'application/json'},
-                    body: JSON.stringify({ soft: true })
+                    body: JSON.stringify({ soft: true, ip: sirenIp })
                 }).then(r => r.json()).then(data => {
                     console.log('Soft kill sent (20 Hz)');
                     // Clear all siren circles
@@ -1124,10 +1193,11 @@
                 });
             } else if (e.key === "K") {
                 // Hard kill - send 0 Hz to stop voices immediately
+                const sirenIp = document.getElementById('sirenIp').value || "192.168.4.200";
                 fetch('/api/kill-siren', {
                     method: 'POST',
                     headers: {'Content-Type': 'application/json'},
-                    body: JSON.stringify({ soft: false })
+                    body: JSON.stringify({ soft: false, ip: sirenIp })
                 }).then(r => r.json()).then(data => {
                     console.log('Hard kill sent (0 Hz)');
                     // Clear all siren circles
diff --git a/webapp/server.py b/webapp/server.py
index 3556675..fc4a4aa 100644
--- a/webapp/server.py
+++ b/webapp/server.py
@@ -14,7 +14,7 @@ import sys
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
 from src.pitch import Pitch
-from src.osc_sender import OSCSender
+from src.osc_sender import OSCSender, cancel_ramp
 from fractions import Fraction
 
 app = Flask(__name__)
@@ -27,6 +27,9 @@ DEFAULT_FILE = "output_chords.json"  # default file
 current_index = 0
 chords = []
 
+# Track last frequency per voice per siren IP (in-memory)
+last_frequencies = {}  # {ip: {voice_index: frequency}}
+
 # OSC settings
 fundamental = 110.0
 osc_sender = OSCSender(ip="127.0.0.1", port=57120, fundamental=fundamental)
@@ -132,6 +135,7 @@ def play_siren():
 
     chord_index = data.get("chordIndex")
     node_index = data.get("nodeIndex")
+    siren_ip = data.get("ip", "192.168.4.200")  # Default to actual siren IP
 
     if chord_index is None or node_index is None:
         return jsonify({"error": "Missing chordIndex/nodeIndex"}), 400
@@ -148,16 +152,20 @@ def play_siren():
     frequency = fundamental * float(fraction)
     voice = node_index + 1  # 1-indexed
 
-    # Send to siren (192.168.4.200:54001) using current fundamental
-    siren_sender = OSCSender(ip="192.168.4.200", port=54001, fundamental=fundamental)
+    # Send to siren using provided or default IP
+    siren_sender = OSCSender(ip=siren_ip, port=54001, fundamental=fundamental)
     siren_sender.set_chords(chords)  # Set chords to ensure proper voice count
     siren_sender.send_single(frequency, voice)
 
+    # Track frequency per voice (0-indexed)
+    last_frequencies.setdefault(siren_ip, {})[node_index] = frequency
+
     return jsonify(
         {
             "frequency": frequency,
             "voice": voice,
             "destination": "siren",
+            "ip": siren_ip,
         }
     )
 
@@ -167,20 +175,95 @@ def kill_siren():
     """Send kill message to siren (soft or hard)."""
     data = request.json
     soft = data.get("soft", True)  # default to soft kill
+    siren_ip = data.get("ip", "192.168.4.200")  # Default to actual siren IP
 
     kill_freq = 20.0 if soft else 0.0
     kill_type = "soft" if soft else "hard"
 
+    # Cancel any running ramp
+    cancel_ramp()
+
     # Send kill to all voices on siren using send_kill
-    siren_sender = OSCSender(ip="192.168.4.200", port=54001, fundamental=fundamental)
+    siren_sender = OSCSender(ip=siren_ip, port=54001, fundamental=fundamental)
     siren_sender.set_chords(chords)  # Set chords to get correct num_voices
     siren_sender.send_kill(soft=soft)
 
+    # Update tracking: set all voices to kill frequency (20 or 0)
+    if siren_ip in last_frequencies:
+        for voice_idx in last_frequencies[siren_ip]:
+            last_frequencies[siren_ip][voice_idx] = kill_freq
+
     return jsonify(
         {
             "kill_freq": kill_freq,
             "kill_type": kill_type,
             "voices": list(range(1, siren_sender.num_voices + 1)),
+            "ip": siren_ip,
+        }
+    )
+
+
+@app.route("/api/ramp-to-chord", methods=["POST"])
+def ramp_to_chord():
+    """Ramp to a chord or single voice on the siren."""
+    data = request.json
+
+    chord_index = data.get("chordIndex")
+    node_index = data.get("nodeIndex")  # Optional - if present, ramp single voice
+    duration_ms = data.get("duration", 3000)
+    start_freq = data.get("startFreq", 20)
+    siren_ip = data.get("ip", "192.168.4.200")  # Default to actual siren IP
+
+    if chord_index is None:
+        return jsonify({"error": "Missing chordIndex"}), 400
+
+    if chord_index < 0 or chord_index >= len(chords):
+        return jsonify({"error": "Invalid chord index"}), 400
+
+    chord = chords[chord_index]
+
+    # Create OSC sender with provided or default IP
+    siren_sender = OSCSender(ip=siren_ip, port=54001, fundamental=fundamental)
+    siren_sender.set_chords(chords)
+
+    if node_index is not None:
+        # Ramp single voice
+        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)
+
+        # Get current frequency for this voice (or default to 20)
+        current_freqs = last_frequencies.get(siren_ip, {})
+        voice_start_freq = current_freqs.get(node_index, 20)
+
+        siren_sender.ramp_to_chord(frequency, duration_ms, voice_start_freq)
+
+        # Update tracking with target (will be reached after ramp completes)
+        last_frequencies.setdefault(siren_ip, {})[node_index] = frequency
+    else:
+        # Ramp entire chord
+        frequencies = [
+            fundamental * float(Fraction(p.get("fraction", "1"))) for p in chord
+        ]
+
+        # Get current frequencies for each voice (or default to 20)
+        current_freqs = last_frequencies.get(siren_ip, {})
+        start_freqs = [current_freqs.get(i, 20) for i in range(len(frequencies))]
+
+        siren_sender.ramp_to_chord(frequencies, duration_ms, start_freqs)
+
+        # Update tracking with targets (will be reached after ramp completes)
+        for i, freq in enumerate(frequencies):
+            last_frequencies.setdefault(siren_ip, {})[i] = freq
+
+    return jsonify(
+        {
+            "status": "ramping",
+            "chordIndex": chord_index,
+            "voiceIndex": node_index,
+            "duration": duration_ms,
         }
     )