diff --git a/webapp/path_navigator.html b/webapp/path_navigator.html
index ea7a588..101e9b0 100644
--- a/webapp/path_navigator.html
+++ b/webapp/path_navigator.html
@@ -734,7 +734,7 @@
             }
         }
         
-        // Fundamental input - auto-send on Enter, Up/Down arrows, or input change
+        // Fundamental input - send on Enter, Up/Down arrows
         document.getElementById("fundamentalInput").addEventListener("keydown", (e) => {
             if (e.key === "Enter") {
                 e.preventDefault();
@@ -752,10 +752,24 @@
             }
         });
         
-        // Also trigger on input change (for the spinner buttons)
-        document.getElementById("fundamentalInput").addEventListener("input", () => {
-            setFundamental();
-        });
+        async function setFundamental() {
+            const input = document.getElementById("fundamentalInput");
+            const fundamental = parseFloat(input.value);
+            if (!fundamental || fundamental <= 0) {
+                return;
+            }
+            try {
+                const response = await fetch("/api/set-fundamental", {
+                    method: "POST",
+                    headers: {"Content-Type": "application/json"},
+                    body: JSON.stringify({ fundamental: fundamental })
+                });
+                const data = await response.json();
+                console.log("Fundamental set to:", data.fundamental, "Hz");
+            } catch (e) {
+                console.log("Error setting fundamental", e);
+            }
+        }
         
         // File input handler
         document.getElementById("loadFileBtn").addEventListener("click", async () => {