diff --git a/Project/fractalNoteEcho.js b/Project/fractalNoteEcho.js
index 5497cb2..996659e 100644
--- a/Project/fractalNoteEcho.js
+++ b/Project/fractalNoteEcho.js
@@ -274,6 +274,14 @@ function makeTask(r, n, v) {
         if (options[INLET_SCALE_AWARE]) {
             // get base note, look up
             var baseIdx = scaleMeta.notes.indexOf(n);
+            while (baseIdx < 0 && n > 0) {
+                n -= 1;
+                baseIdx = scaleMeta.notes.indexOf(n);
+            }
+            if (baseIdx < 0) {
+                // invalid something or another
+                return;
+            }
             var newIdx = baseIdx + r.note_incr;
             n = scaleMeta.notes[newIdx];
             //log('NOTE: ' + n + ' base:' + baseIdx + ' new:' + newIdx)
diff --git a/src/fractalNoteEcho.ts b/src/fractalNoteEcho.ts
index 25e3e80..bf47b75 100644
--- a/src/fractalNoteEcho.ts
+++ b/src/fractalNoteEcho.ts
@@ -305,7 +305,15 @@ function makeTask(r: NoteMeta, n: number, v: number) {
   return function () {
     if (options[INLET_SCALE_AWARE]) {
       // get base note, look up
-      const baseIdx = scaleMeta.notes.indexOf(n)
+      let baseIdx = scaleMeta.notes.indexOf(n)
+      while (baseIdx < 0 && n > 0) {
+        n -= 1
+        baseIdx = scaleMeta.notes.indexOf(n)
+      }
+      if (baseIdx < 0) {
+        // invalid something or another
+        return
+      }
       const newIdx = baseIdx + r.note_incr
       n = scaleMeta.notes[newIdx]
       //log('NOTE: ' + n + ' base:' + baseIdx + ' new:' + newIdx)