diff --git a/.claude/settings.local.json b/.claude/settings.local.json
index c9d0425..9495fd2 100644
--- a/.claude/settings.local.json
+++ b/.claude/settings.local.json
@@ -9,7 +9,8 @@
       "Bash(wc:*)",
       "Bash(ls:*)",
       "Bash(node -c:*)",
-      "Bash(npm run lint:*)"
+      "Bash(npm run lint:*)",
+      "Bash(python:*)"
     ]
   }
 }
diff --git a/backend/builder/service.py b/backend/builder/service.py
index bec2aa4..b7e0fe7 100644
--- a/backend/builder/service.py
+++ b/backend/builder/service.py
@@ -11,7 +11,7 @@ from fastapi import HTTPException
 logger = logging.getLogger("builder.service")
 
 # Storage directory for built .bsm files
-STORAGE_DIR = Path("storage/built_melodies")
+STORAGE_DIR = Path(__file__).parent.parent / "storage" / "built_melodies"
 
 
 def _ensure_storage_dir():
diff --git a/backend/mqtt_data.db b/backend/mqtt_data.db
new file mode 100644
index 0000000..e69de29
diff --git a/frontend/src/melodies/MelodyDetail.jsx b/frontend/src/melodies/MelodyDetail.jsx
index 74c4df6..a101d37 100644
--- a/frontend/src/melodies/MelodyDetail.jsx
+++ b/frontend/src/melodies/MelodyDetail.jsx
@@ -443,6 +443,7 @@ export default function MelodyDetail() {
       <SpeedCalculatorModal
         open={showSpeedCalc}
         melody={melody}
+        builtMelody={builtMelody}
         onClose={() => setShowSpeedCalc(false)}
         onSaved={() => {
           setShowSpeedCalc(false);
diff --git a/frontend/src/melodies/MelodyForm.jsx b/frontend/src/melodies/MelodyForm.jsx
index 6f90df8..255011a 100644
--- a/frontend/src/melodies/MelodyForm.jsx
+++ b/frontend/src/melodies/MelodyForm.jsx
@@ -4,6 +4,7 @@ import api from "../api/client";
 import TranslationModal from "./TranslationModal";
 import SelectBuiltMelodyModal from "./builder/SelectBuiltMelodyModal";
 import BuildOnTheFlyModal from "./builder/BuildOnTheFlyModal";
+import SpeedCalculatorModal from "./SpeedCalculatorModal";
 import {
   getLocalizedValue,
   getLanguageName,
@@ -84,6 +85,8 @@ export default function MelodyForm() {
 
   const [showSelectBuilt, setShowSelectBuilt] = useState(false);
   const [showBuildOnTheFly, setShowBuildOnTheFly] = useState(false);
+  const [showSpeedCalc, setShowSpeedCalc] = useState(false);
+  const [builtMelody, setBuiltMelody] = useState(null);
 
   useEffect(() => {
     api.get("/settings/melody").then((ms) => {
@@ -124,6 +127,13 @@ export default function MelodyForm() {
       setPid(melody.pid || "");
       setMelodyStatus(melody.status || "published");
       setExistingFiles(files);
+      // Load built melody assignment (non-fatal)
+      try {
+        const bm = await api.get(`/builder/melodies/for-melody/${id}`);
+        setBuiltMelody(bm || null);
+      } catch {
+        setBuiltMelody(null);
+      }
     } catch (err) {
       setError(err.message);
     } finally {
@@ -259,6 +269,16 @@ export default function MelodyForm() {
           {isEdit ? "Edit Melody" : "Add Melody"}
         </h1>
         <div className="flex gap-3">
+          {isEdit && (
+            <button
+              type="button"
+              onClick={() => setShowSpeedCalc(true)}
+              className="px-4 py-2 text-sm rounded-md transition-colors"
+              style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-primary)", border: "1px solid var(--border-primary)" }}
+            >
+              Speed Calculator
+            </button>
+          )}
           <button
             type="button"
             onClick={() => navigate(isEdit ? `/melodies/${id}` : "/melodies")}
@@ -610,6 +630,13 @@ export default function MelodyForm() {
 
       {isEdit && (
         <>
+          <SpeedCalculatorModal
+            open={showSpeedCalc}
+            melody={{ id, information, default_settings: settings, type, url, uid, pid }}
+            builtMelody={builtMelody}
+            onClose={() => setShowSpeedCalc(false)}
+            onSaved={() => { setShowSpeedCalc(false); loadMelody(); }}
+          />
           <SelectBuiltMelodyModal
             open={showSelectBuilt}
             melodyId={id}
diff --git a/frontend/src/melodies/SpeedCalculatorModal.jsx b/frontend/src/melodies/SpeedCalculatorModal.jsx
index 03ce2d0..21970fd 100644
--- a/frontend/src/melodies/SpeedCalculatorModal.jsx
+++ b/frontend/src/melodies/SpeedCalculatorModal.jsx
@@ -35,7 +35,7 @@ function playStep(audioCtx, stepValue, beatDurationMs) {
 
       gain.gain.setValueAtTime(0, now);
       gain.gain.linearRampToValueAtTime(0.3, now + fadeIn);
-      gain.gain.setValueAtTime(0.3, now + duration - fadeOut);
+      gain.gain.setValueAtTime(0.3, now + Math.max(duration - fadeOut, fadeIn + 0.001));
       gain.gain.linearRampToValueAtTime(0, now + duration);
 
       osc.start(now);
@@ -45,7 +45,7 @@ function playStep(audioCtx, stepValue, beatDurationMs) {
 }
 
 // ============================================================================
-// Parse raw steps string into list of uint16 values
+// Parse / decode helpers
 // ============================================================================
 
 function parseBellNotation(notation) {
@@ -72,10 +72,28 @@ function getActiveBells(stepValue) {
   return bells;
 }
 
+/** Decode a .bsm binary (big-endian uint16 per step) to uint16 array */
+async function decodeBsmBinary(url) {
+  const token = localStorage.getItem("access_token");
+  const res = await fetch(url, {
+    headers: token ? { Authorization: `Bearer ${token}` } : {},
+  });
+  if (!res.ok) throw new Error(`Failed to fetch binary: ${res.statusText}`);
+  const buf = await res.arrayBuffer();
+  const view = new DataView(buf);
+  const steps = [];
+  for (let i = 0; i + 1 < buf.byteLength; i += 2) {
+    steps.push(view.getUint16(i, false)); // big-endian
+  }
+  return steps;
+}
+
 // ============================================================================
 // Speed math
 // MIN is derived so that at 50%, speed = normal (geometric mean)
 // normal = sqrt(MIN * MAX)  =>  MIN = normal^2 / MAX
+// Note: higher ms = SLOWER. MAX ms = fastest hardware speed.
+// Normal ms must be HIGHER (slower) than MAX ms to make sense.
 // ============================================================================
 
 function calcMin(normal, max) {
@@ -90,27 +108,47 @@ function calcMin(normal, max) {
 const labelStyle = { color: "var(--text-secondary)" };
 const mutedStyle = { color: "var(--text-muted)" };
 
-export default function SpeedCalculatorModal({ open, melody, onClose, onSaved }) {
+// Step Delay slider is inverted: right = fast (low ms), left = slow (high ms)
+// We store actual ms in state, but display with inverted slider value.
+const DELAY_MIN = 50;
+const DELAY_MAX = 3000;
+function delayToSlider(ms) { return DELAY_MIN + DELAY_MAX - ms; }
+function sliderToDelay(val) { return DELAY_MIN + DELAY_MAX - val; }
+
+export default function SpeedCalculatorModal({ open, melody, builtMelody, onClose, onSaved }) {
   const info = melody?.information || {};
 
-  // Raw steps input (not stored in Firestore — only used locally for playback)
+  // Raw steps input
   const [stepsInput, setStepsInput] = useState("");
-  const [steps, setSteps] = useState([]); // parsed uint16 values
+  const [steps, setSteps] = useState([]);
+  const [loadingBinary, setLoadingBinary] = useState(false);
+  const [binaryLoadError, setBinaryLoadError] = useState("");
 
   // Playback
   const audioCtxRef = useRef(null);
   const playbackRef = useRef(null); // { timer, stepIndex }
+  const stepsRef = useRef([]);
+  const stepDelayRef = useRef(500);
+  const effectiveBeatRef = useRef(100);
+  const loopRef = useRef(false);
+
   const [playing, setPlaying] = useState(false);
   const [paused, setPaused] = useState(false);
   const [loop, setLoop] = useState(false);
   const [currentStep, setCurrentStep] = useState(-1);
 
   // Sliders
-  const [stepDelay, setStepDelay] = useState(500); // ms
-  const [beatDuration, setBeatDuration] = useState(100); // ms
+  const [stepDelay, setStepDelay] = useState(500);
+  const [beatDuration, setBeatDuration] = useState(100);
 
   const effectiveBeat = Math.min(beatDuration, Math.max(20, stepDelay - 20));
 
+  // Keep refs in sync so playback loop always reads current values
+  useEffect(() => { stepsRef.current = steps; }, [steps]);
+  useEffect(() => { stepDelayRef.current = stepDelay; }, [stepDelay]);
+  useEffect(() => { effectiveBeatRef.current = effectiveBeat; }, [effectiveBeat]);
+  useEffect(() => { loopRef.current = loop; }, [loop]);
+
   // Speed capture
   const [capturedMax, setCapturedMax] = useState(null);
   const [capturedNormal, setCapturedNormal] = useState(null);
@@ -120,22 +158,27 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
   const [saveError, setSaveError] = useState("");
   const [saveSuccess, setSaveSuccess] = useState(false);
 
-  // Warnings
+  // Warnings:
+  // MAX is the fastest (lowest ms). Normal must be > MAX (slower than MAX).
+  // If Normal < MAX, it means Normal is faster than MAX — nonsensical.
   const maxWarning = capturedMax !== null && capturedMax < 100;
-  const orderWarning = capturedMax !== null && capturedNormal !== null && capturedNormal > capturedMax;
+  const orderWarning = capturedMax !== null && capturedNormal !== null && capturedNormal < capturedMax;
 
-  // Pre-fill existing speeds from melody
+  // Reset on open
   useEffect(() => {
     if (open) {
       setCapturedMax(info.maxSpeed > 0 ? info.maxSpeed : null);
       setCapturedNormal(null);
       setStepsInput("");
       setSteps([]);
+      setBinaryLoadError("");
       setCurrentStep(-1);
       setPlaying(false);
       setPaused(false);
+      setSaveError("");
+      setSaveSuccess(false);
     }
-  }, [open]);
+  }, [open]); // eslint-disable-line react-hooks/exhaustive-deps
 
   const stopPlayback = useCallback(() => {
     if (playbackRef.current) {
@@ -147,7 +190,6 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
     setCurrentStep(-1);
   }, []);
 
-  // Stop when modal closes
   useEffect(() => {
     if (!open) stopPlayback();
   }, [open, stopPlayback]);
@@ -162,44 +204,51 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
     return audioCtxRef.current;
   };
 
-  const scheduleStep = useCallback(
-    (stepIndex, startFrom = 0) => {
-      if (!steps.length) return;
+  // Recursive scheduler using refs for live updates — no restart needed when sliders change
+  const scheduleStep = useCallback((stepIndex) => {
+    const currentSteps = stepsRef.current;
+    if (!currentSteps.length) return;
 
-      const playFrom = stepIndex % steps.length;
-      if (!loop && playFrom === 0 && stepIndex > 0) {
-        stopPlayback();
-        return;
-      }
+    const playFrom = stepIndex % currentSteps.length;
 
-      const ctx = ensureAudioCtx();
-      const stepValue = steps[playFrom];
+    // End of sequence without loop
+    if (!loopRef.current && playFrom === 0 && stepIndex > 0) {
+      setPlaying(false);
+      setPaused(false);
+      setCurrentStep(-1);
+      playbackRef.current = null;
+      return;
+    }
 
-      setCurrentStep(playFrom);
-      playStep(ctx, stepValue, effectiveBeat);
+    const ctx = ensureAudioCtx();
+    const stepValue = currentSteps[playFrom];
 
-      const timer = setTimeout(() => {
-        const next = playFrom + 1;
-        if (next >= steps.length) {
-          if (loop) {
-            scheduleStep(0);
-          } else {
-            stopPlayback();
-          }
+    setCurrentStep(playFrom);
+    playStep(ctx, stepValue, effectiveBeatRef.current);
+
+    const delay = stepDelayRef.current;
+    const timer = setTimeout(() => {
+      const next = playFrom + 1;
+      if (next >= stepsRef.current.length) {
+        if (loopRef.current) {
+          scheduleStep(0);
         } else {
-          scheduleStep(next);
+          setPlaying(false);
+          setPaused(false);
+          setCurrentStep(-1);
+          playbackRef.current = null;
         }
-      }, stepDelay);
+      } else {
+        scheduleStep(next);
+      }
+    }, delay);
 
-      playbackRef.current = { timer, stepIndex: playFrom };
-    },
-    [steps, stepDelay, effectiveBeat, loop, stopPlayback]
-  );
+    playbackRef.current = { timer, stepIndex: playFrom };
+  }, []); // no deps — reads everything from refs
 
   const handlePlay = () => {
-    if (!steps.length) return;
+    if (!stepsRef.current.length) return;
     if (paused && playbackRef.current) {
-      // Resume from current step
       setPaused(false);
       setPlaying(true);
       scheduleStep(playbackRef.current.stepIndex);
@@ -218,14 +267,34 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
     setPlaying(false);
   };
 
-  const handleStop = () => {
-    stopPlayback();
-  };
-
   const handleStepsParse = () => {
     const parsed = parseStepsString(stepsInput);
     setSteps(parsed);
+    stepsRef.current = parsed;
     stopPlayback();
+    setBinaryLoadError("");
+  };
+
+  const handleLoadFromBinary = async () => {
+    if (!builtMelody?.binary_url) return;
+    setLoadingBinary(true);
+    setBinaryLoadError("");
+    try {
+      const decoded = await decodeBsmBinary(`/api${builtMelody.binary_url}`);
+      setSteps(decoded);
+      stepsRef.current = decoded;
+      stopPlayback();
+      // Also reconstruct a human-readable steps string for the textarea
+      const stepsStr = decoded.map((v) => {
+        if (!v) return "0";
+        return getActiveBells(v).join("+");
+      }).join(",");
+      setStepsInput(stepsStr);
+    } catch (err) {
+      setBinaryLoadError(err.message);
+    } finally {
+      setLoadingBinary(false);
+    }
   };
 
   const handleSetSliderToCapture = (value) => {
@@ -233,7 +302,7 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
   };
 
   const handleSave = async () => {
-    if (!capturedMax || !derivedMin) return;
+    if (!capturedMax || !capturedNormal || !derivedMin) return;
     setSaving(true);
     setSaveError("");
     setSaveSuccess(false);
@@ -251,9 +320,7 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
         pid: melody.pid,
       });
       setSaveSuccess(true);
-      setTimeout(() => {
-        onSaved();
-      }, 800);
+      setTimeout(() => onSaved(), 800);
     } catch (err) {
       setSaveError(err.message);
     } finally {
@@ -269,6 +336,7 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
     return set;
   }, new Set());
   const currentBells = currentStep >= 0 ? getActiveBells(steps[currentStep] || 0) : [];
+  const maxBell = allBellsUsed.size > 0 ? Math.max(...Array.from(allBellsUsed)) : 0;
 
   return (
     <div
@@ -277,11 +345,18 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
       onClick={(e) => e.target === e.currentTarget && !playing && onClose()}
     >
       <div
-        className="w-full max-w-2xl rounded-lg border shadow-xl"
-        style={{ backgroundColor: "var(--bg-card)", borderColor: "var(--border-primary)", maxHeight: "90vh", overflowY: "auto" }}
+        className="w-full rounded-lg border shadow-xl"
+        style={{
+          backgroundColor: "var(--bg-card)",
+          borderColor: "var(--border-primary)",
+          maxWidth: "900px",
+          maxHeight: "92vh",
+          display: "flex",
+          flexDirection: "column",
+        }}
       >
         {/* Header */}
-        <div className="flex items-center justify-between px-6 py-4 border-b" style={{ borderColor: "var(--border-primary)" }}>
+        <div className="flex items-center justify-between px-6 py-4 border-b flex-shrink-0" style={{ borderColor: "var(--border-primary)" }}>
           <div>
             <h2 className="text-lg font-semibold" style={{ color: "var(--text-heading)" }}>Speed Calculator</h2>
             <p className="text-xs mt-0.5" style={mutedStyle}>
@@ -291,254 +366,279 @@ export default function SpeedCalculatorModal({ open, melody, onClose, onSaved })
           <button onClick={() => { stopPlayback(); onClose(); }} className="text-xl leading-none" style={mutedStyle}>&times;</button>
         </div>
 
-        <div className="p-6 space-y-5">
-          {/* Steps Input */}
-          <div>
-            <label className="block text-sm font-medium mb-1" style={labelStyle}>
-              Melody Steps
-              <span className="font-normal ml-2" style={mutedStyle}>(paste your step notation)</span>
-            </label>
-            <div className="flex gap-2">
-              <textarea
-                value={stepsInput}
-                onChange={(e) => setStepsInput(e.target.value)}
-                rows={2}
-                placeholder="e.g. 1,2,2+1,1,2,3+1,0,3,2..."
-                className="flex-1 px-3 py-2 rounded-md text-sm border"
-                style={{ fontFamily: "monospace", resize: "none" }}
-              />
-              <button
-                onClick={handleStepsParse}
-                className="px-4 py-2 text-sm rounded-md self-start transition-colors"
-                style={{ backgroundColor: "var(--btn-primary)", color: "var(--text-white)" }}
-              >
-                Load
-              </button>
-            </div>
-            {totalSteps > 0 && (
-              <p className="text-xs mt-1" style={{ color: "var(--success-text)" }}>
-                {totalSteps} steps loaded &nbsp;·&nbsp; {allBellsUsed.size} unique bell{allBellsUsed.size !== 1 ? "s" : ""} used
-              </p>
-            )}
-          </div>
+        {/* Two-column body */}
+        <div className="flex-1 overflow-y-auto">
+          <div style={{ display: "grid", gridTemplateColumns: "1fr 1fr", gap: "0", minHeight: 0 }}>
 
-          {/* Bell visualizer */}
-          {totalSteps > 0 && (
-            <div>
-              <p className="text-xs mb-2" style={mutedStyle}>Bell indicator (current step)</p>
-              <div className="flex flex-wrap gap-1.5">
-                {Array.from({ length: Math.max(...Array.from(allBellsUsed), 1) }, (_, i) => i + 1).map((b) => {
-                  const isActive = currentBells.includes(b);
-                  const isUsed = allBellsUsed.has(b);
-                  return (
-                    <div
-                      key={b}
-                      className="w-8 h-8 rounded-full flex items-center justify-center text-xs font-bold transition-all"
-                      style={{
-                        backgroundColor: isActive
-                          ? "var(--accent)"
-                          : isUsed
-                          ? "var(--bg-card-hover)"
-                          : "var(--bg-primary)",
-                        color: isActive ? "var(--bg-primary)" : isUsed ? "var(--text-secondary)" : "var(--border-primary)",
-                        border: `2px solid ${isActive ? "var(--accent)" : isUsed ? "var(--border-primary)" : "var(--border-primary)"}`,
-                        transform: isActive ? "scale(1.2)" : "scale(1)",
-                      }}
+            {/* LEFT COLUMN: Steps, visualizer, controls, sliders */}
+            <div className="p-6 space-y-5 border-r" style={{ borderColor: "var(--border-primary)" }}>
+
+              {/* Steps Input */}
+              <div>
+                <div className="flex items-center justify-between mb-1">
+                  <label className="text-sm font-medium" style={labelStyle}>
+                    Melody Steps
+                  </label>
+                  {builtMelody?.binary_url && (
+                    <button
+                      onClick={handleLoadFromBinary}
+                      disabled={loadingBinary}
+                      className="text-xs px-2 py-1 rounded transition-colors disabled:opacity-50"
+                      style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-secondary)", border: "1px solid var(--border-primary)" }}
                     >
-                      {b}
+                      {loadingBinary ? "Loading..." : "Load from Binary"}
+                    </button>
+                  )}
+                </div>
+                {binaryLoadError && (
+                  <p className="text-xs mb-1" style={{ color: "var(--danger-text)" }}>{binaryLoadError}</p>
+                )}
+                <div className="flex gap-2">
+                  <textarea
+                    value={stepsInput}
+                    onChange={(e) => setStepsInput(e.target.value)}
+                    rows={3}
+                    placeholder="e.g. 1,2,2+1,1,2,3+1,0,3,2..."
+                    className="flex-1 px-3 py-2 rounded-md text-sm border"
+                    style={{ fontFamily: "monospace", resize: "none" }}
+                  />
+                  <button
+                    onClick={handleStepsParse}
+                    className="px-3 py-2 text-sm rounded-md self-start transition-colors"
+                    style={{ backgroundColor: "var(--btn-primary)", color: "var(--text-white)" }}
+                  >
+                    Load
+                  </button>
+                </div>
+                {totalSteps > 0 && (
+                  <p className="text-xs mt-1" style={{ color: "var(--success-text)" }}>
+                    {totalSteps} steps &nbsp;·&nbsp; {allBellsUsed.size} bell{allBellsUsed.size !== 1 ? "s" : ""}
+                  </p>
+                )}
+              </div>
+
+              {/* Bell visualizer */}
+              {totalSteps > 0 && (
+                <div>
+                  <p className="text-xs mb-2" style={mutedStyle}>
+                    Bell indicator
+                    {currentStep >= 0 && <span> &nbsp;·&nbsp; Step {currentStep + 1} / {totalSteps}</span>}
+                  </p>
+                  <div className="flex flex-wrap gap-1.5">
+                    {Array.from({ length: maxBell }, (_, i) => i + 1).map((b) => {
+                      const isActive = currentBells.includes(b);
+                      const isUsed = allBellsUsed.has(b);
+                      return (
+                        <div
+                          key={b}
+                          className="w-7 h-7 rounded-full flex items-center justify-center text-xs font-bold transition-all"
+                          style={{
+                            backgroundColor: isActive ? "var(--accent)" : isUsed ? "var(--bg-card-hover)" : "var(--bg-primary)",
+                            color: isActive ? "var(--bg-primary)" : isUsed ? "var(--text-secondary)" : "var(--border-primary)",
+                            border: `2px solid ${isActive ? "var(--accent)" : "var(--border-primary)"}`,
+                            transform: isActive ? "scale(1.2)" : "scale(1)",
+                          }}
+                        >
+                          {b}
+                        </div>
+                      );
+                    })}
+                  </div>
+                </div>
+              )}
+
+              {/* Playback Controls */}
+              <div className="flex items-center gap-2">
+                {!playing ? (
+                  <button
+                    onClick={handlePlay}
+                    disabled={!totalSteps}
+                    className="px-4 py-2 text-sm rounded-md disabled:opacity-40 transition-colors font-medium"
+                    style={{ backgroundColor: "var(--btn-primary)", color: "var(--text-white)" }}
+                  >
+                    {paused ? "Resume" : "Play"}
+                  </button>
+                ) : (
+                  <button
+                    onClick={handlePause}
+                    className="px-4 py-2 text-sm rounded-md transition-colors font-medium"
+                    style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-primary)", border: "1px solid var(--border-primary)" }}
+                  >
+                    Pause
+                  </button>
+                )}
+                <button
+                  onClick={stopPlayback}
+                  disabled={!playing && !paused}
+                  className="px-4 py-2 text-sm rounded-md disabled:opacity-40 transition-colors"
+                  style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-primary)", border: "1px solid var(--border-primary)" }}
+                >
+                  Stop
+                </button>
+                <label className="flex items-center gap-1.5 ml-1 text-sm cursor-pointer" style={labelStyle}>
+                  <input
+                    type="checkbox"
+                    checked={loop}
+                    onChange={(e) => { setLoop(e.target.checked); loopRef.current = e.target.checked; }}
+                    className="h-4 w-4 rounded"
+                  />
+                  Loop
+                </label>
+              </div>
+
+              {/* Step Delay Slider — inverted: right = fast (low ms) */}
+              <div>
+                <div className="flex items-center justify-between mb-1">
+                  <label className="text-sm font-medium" style={labelStyle}>Step Delay (Speed)</label>
+                  <span className="text-sm font-bold" style={{ color: "var(--accent)" }}>{stepDelay} ms</span>
+                </div>
+                <input
+                  type="range"
+                  min={DELAY_MIN}
+                  max={DELAY_MAX}
+                  step="10"
+                  value={delayToSlider(stepDelay)}
+                  onChange={(e) => setStepDelay(sliderToDelay(Number(e.target.value)))}
+                  className="w-full h-2 rounded-lg appearance-none cursor-pointer"
+                />
+                <div className="flex justify-between text-xs mt-0.5" style={mutedStyle}>
+                  <span>Slow (3000ms)</span>
+                  <span>Fast (50ms)</span>
+                </div>
+              </div>
+
+              {/* Beat Duration Slider */}
+              <div>
+                <div className="flex items-center justify-between mb-1">
+                  <label className="text-sm font-medium" style={labelStyle}>Tone Length</label>
+                  <span className="text-sm" style={mutedStyle}>
+                    {effectiveBeat} ms
+                    {effectiveBeat < beatDuration && <span style={{ color: "var(--warning, #f59e0b)" }}> (capped)</span>}
+                  </span>
+                </div>
+                <input
+                  type="range"
+                  min="20"
+                  max="500"
+                  step="5"
+                  value={beatDuration}
+                  onChange={(e) => setBeatDuration(Number(e.target.value))}
+                  className="w-full h-2 rounded-lg appearance-none cursor-pointer"
+                />
+                <div className="flex justify-between text-xs mt-0.5" style={mutedStyle}>
+                  <span>20ms (short)</span>
+                  <span>500ms (long)</span>
+                </div>
+              </div>
+            </div>
+
+            {/* RIGHT COLUMN: Speed Capture */}
+            <div className="p-6">
+              <div className="rounded-lg border p-4 space-y-4 h-full" style={{ borderColor: "var(--border-primary)", backgroundColor: "var(--bg-primary)" }}>
+                <div>
+                  <h3 className="text-sm font-semibold" style={{ color: "var(--text-heading)" }}>Speed Capture</h3>
+                  <p className="text-xs mt-1" style={mutedStyle}>
+                    Play and find the fastest speed the controller can handle (MAX). Then find a speed that feels natural (Normal). MIN is auto-derived so that 50% slider = Normal.
+                  </p>
+                </div>
+
+                {/* MAX */}
+                <div className="rounded-md p-3 border" style={{ borderColor: "var(--border-primary)", backgroundColor: "var(--bg-card)" }}>
+                  <span className="text-xs font-semibold uppercase tracking-wide block mb-2" style={{ color: "var(--text-muted)" }}>MAX — fastest safe</span>
+                  <div className="flex items-center justify-between">
+                    <span className="text-2xl font-bold" style={{ color: capturedMax !== null ? "var(--accent)" : "var(--text-muted)" }}>
+                      {capturedMax !== null ? `${capturedMax} ms` : "—"}
+                    </span>
+                    <div className="flex gap-2">
+                      <button
+                        onClick={() => handleSetSliderToCapture(capturedMax)}
+                        disabled={capturedMax === null}
+                        className="px-2 py-1 text-xs rounded disabled:opacity-40 transition-colors"
+                        style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-muted)", border: "1px solid var(--border-primary)" }}
+                        title="Set slider to this value"
+                      >
+                        Set ↑
+                      </button>
+                      <button
+                        onClick={() => setCapturedMax(stepDelay)}
+                        className="px-3 py-1.5 text-xs rounded-md transition-colors font-medium"
+                        style={{ backgroundColor: "var(--btn-primary)", color: "var(--text-white)" }}
+                      >
+                        Capture
+                      </button>
                     </div>
-                  );
-                })}
-              </div>
-              {currentStep >= 0 && (
-                <p className="text-xs mt-1" style={mutedStyle}>
-                  Step {currentStep + 1} / {totalSteps}
-                </p>
-              )}
-            </div>
-          )}
-
-          {/* Playback Controls */}
-          <div className="flex items-center gap-3">
-            {!playing ? (
-              <button
-                onClick={handlePlay}
-                disabled={!totalSteps}
-                className="px-4 py-2 text-sm rounded-md disabled:opacity-40 transition-colors font-medium"
-                style={{ backgroundColor: "var(--btn-primary)", color: "var(--text-white)" }}
-              >
-                {paused ? "Resume" : "Play"}
-              </button>
-            ) : (
-              <button
-                onClick={handlePause}
-                className="px-4 py-2 text-sm rounded-md transition-colors font-medium"
-                style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-primary)", border: "1px solid var(--border-primary)" }}
-              >
-                Pause
-              </button>
-            )}
-            <button
-              onClick={handleStop}
-              disabled={!playing && !paused}
-              className="px-4 py-2 text-sm rounded-md disabled:opacity-40 transition-colors"
-              style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-primary)", border: "1px solid var(--border-primary)" }}
-            >
-              Stop
-            </button>
-            <label className="flex items-center gap-2 ml-2 text-sm cursor-pointer" style={labelStyle}>
-              <input type="checkbox" checked={loop} onChange={(e) => setLoop(e.target.checked)} className="h-4 w-4 rounded" />
-              Loop
-            </label>
-          </div>
-
-          {/* Step Delay Slider */}
-          <div>
-            <div className="flex items-center justify-between mb-1">
-              <label className="text-sm font-medium" style={labelStyle}>Step Delay (Speed)</label>
-              <span className="text-sm font-bold" style={{ color: "var(--accent)" }}>{stepDelay} ms</span>
-            </div>
-            <input
-              type="range"
-              min="50"
-              max="3000"
-              step="10"
-              value={stepDelay}
-              onChange={(e) => setStepDelay(Number(e.target.value))}
-              className="w-full h-2 rounded-lg appearance-none cursor-pointer"
-            />
-            <div className="flex justify-between text-xs mt-0.5" style={mutedStyle}>
-              <span>50ms (fastest)</span>
-              <span>3000ms (slowest)</span>
-            </div>
-          </div>
-
-          {/* Beat Duration Slider */}
-          <div>
-            <div className="flex items-center justify-between mb-1">
-              <label className="text-sm font-medium" style={labelStyle}>Tone Length</label>
-              <span className="text-sm" style={mutedStyle}>
-                {effectiveBeat} ms
-                {effectiveBeat < beatDuration && <span style={{ color: "var(--warning, #f59e0b)" }}> (capped)</span>}
-              </span>
-            </div>
-            <input
-              type="range"
-              min="20"
-              max="500"
-              step="5"
-              value={beatDuration}
-              onChange={(e) => setBeatDuration(Number(e.target.value))}
-              className="w-full h-2 rounded-lg appearance-none cursor-pointer"
-            />
-            <div className="flex justify-between text-xs mt-0.5" style={mutedStyle}>
-              <span>20ms (short)</span>
-              <span>500ms (long)</span>
-            </div>
-          </div>
-
-          {/* Speed Capture Panel */}
-          <div className="rounded-lg border p-4 space-y-3" style={{ borderColor: "var(--border-primary)", backgroundColor: "var(--bg-primary)" }}>
-            <h3 className="text-sm font-semibold" style={{ color: "var(--text-heading)" }}>Speed Capture</h3>
-            <p className="text-xs" style={mutedStyle}>
-              Find the fastest speed the controller can handle (MAX), then find the speed that feels "normal" (Normal).
-              MIN is auto-calculated so that 50% = Normal speed.
-            </p>
-
-            {/* MAX */}
-            <div className="flex items-center gap-3">
-              <div className="flex-1">
-                <span className="text-xs font-medium block mb-0.5" style={labelStyle}>MAX (fastest safe)</span>
-                <div className="flex items-center gap-2">
-                  <span className="text-lg font-bold w-20" style={{ color: capturedMax ? "var(--accent)" : "var(--text-muted)" }}>
-                    {capturedMax !== null ? `${capturedMax} ms` : "—"}
-                  </span>
-                  <button
-                    onClick={() => handleSetSliderToCapture(capturedMax)}
-                    disabled={capturedMax === null}
-                    className="px-2 py-1 text-xs rounded disabled:opacity-40 transition-colors"
-                    style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-muted)", border: "1px solid var(--border-primary)" }}
-                    title="Load this value to slider"
-                  >
-                    Set ↑
-                  </button>
+                  </div>
                 </div>
-              </div>
-              <button
-                onClick={() => setCapturedMax(stepDelay)}
-                className="px-3 py-2 text-xs rounded-md transition-colors font-medium"
-                style={{ backgroundColor: "var(--btn-primary)", color: "var(--text-white)" }}
-              >
-                Capture
-              </button>
-            </div>
 
-            {/* Normal */}
-            <div className="flex items-center gap-3">
-              <div className="flex-1">
-                <span className="text-xs font-medium block mb-0.5" style={labelStyle}>Normal (50% speed feel)</span>
-                <div className="flex items-center gap-2">
-                  <span className="text-lg font-bold w-20" style={{ color: capturedNormal ? "var(--accent)" : "var(--text-muted)" }}>
-                    {capturedNormal !== null ? `${capturedNormal} ms` : "—"}
-                  </span>
-                  <button
-                    onClick={() => handleSetSliderToCapture(capturedNormal)}
-                    disabled={capturedNormal === null}
-                    className="px-2 py-1 text-xs rounded disabled:opacity-40 transition-colors"
-                    style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-muted)", border: "1px solid var(--border-primary)" }}
-                    title="Load this value to slider"
-                  >
-                    Set ↑
-                  </button>
+                {/* Normal */}
+                <div className="rounded-md p-3 border" style={{ borderColor: "var(--border-primary)", backgroundColor: "var(--bg-card)" }}>
+                  <span className="text-xs font-semibold uppercase tracking-wide block mb-2" style={{ color: "var(--text-muted)" }}>Normal — at 50% speed</span>
+                  <div className="flex items-center justify-between">
+                    <span className="text-2xl font-bold" style={{ color: capturedNormal !== null ? "var(--accent)" : "var(--text-muted)" }}>
+                      {capturedNormal !== null ? `${capturedNormal} ms` : "—"}
+                    </span>
+                    <div className="flex gap-2">
+                      <button
+                        onClick={() => handleSetSliderToCapture(capturedNormal)}
+                        disabled={capturedNormal === null}
+                        className="px-2 py-1 text-xs rounded disabled:opacity-40 transition-colors"
+                        style={{ backgroundColor: "var(--bg-card-hover)", color: "var(--text-muted)", border: "1px solid var(--border-primary)" }}
+                        title="Set slider to this value"
+                      >
+                        Set ↑
+                      </button>
+                      <button
+                        onClick={() => setCapturedNormal(stepDelay)}
+                        className="px-3 py-1.5 text-xs rounded-md transition-colors font-medium"
+                        style={{ backgroundColor: "var(--btn-primary)", color: "var(--text-white)" }}
+                      >
+                        Capture
+                      </button>
+                    </div>
+                  </div>
                 </div>
-              </div>
-              <button
-                onClick={() => setCapturedNormal(stepDelay)}
-                className="px-3 py-2 text-xs rounded-md transition-colors font-medium"
-                style={{ backgroundColor: "var(--btn-primary)", color: "var(--text-white)" }}
-              >
-                Capture
-              </button>
-            </div>
 
-            {/* MIN (auto-calculated) */}
-            <div className="pt-1 border-t" style={{ borderColor: "var(--border-primary)" }}>
-              <span className="text-xs font-medium block mb-0.5" style={mutedStyle}>MIN (auto-calculated)</span>
-              <span className="text-lg font-bold" style={{ color: derivedMin ? "var(--text-secondary)" : "var(--text-muted)" }}>
-                {derivedMin !== null ? `${derivedMin} ms` : "—"}
-              </span>
-              {derivedMin !== null && (
-                <span className="text-xs ml-2" style={mutedStyle}>(normal² / max)</span>
-              )}
-            </div>
+                {/* MIN (derived) */}
+                <div className="rounded-md p-3 border" style={{ borderColor: "var(--border-primary)", backgroundColor: "var(--bg-card)" }}>
+                  <span className="text-xs font-semibold uppercase tracking-wide block mb-1" style={{ color: "var(--text-muted)" }}>
+                    MIN — auto-calculated
+                    {derivedMin !== null && <span className="font-normal ml-1">(normal² / max)</span>}
+                  </span>
+                  <span className="text-2xl font-bold" style={{ color: derivedMin !== null ? "var(--text-secondary)" : "var(--text-muted)" }}>
+                    {derivedMin !== null ? `${derivedMin} ms` : "—"}
+                  </span>
+                </div>
 
-            {/* Warnings */}
-            {maxWarning && (
-              <div className="text-xs rounded p-2" style={{ backgroundColor: "var(--danger-bg)", color: "var(--danger-text)" }}>
-                Warning: MAX speed of {capturedMax}ms is very fast (&lt;100ms). This could damage the device.
+                {/* Warnings */}
+                {maxWarning && (
+                  <div className="text-xs rounded p-2" style={{ backgroundColor: "var(--danger-bg)", color: "var(--danger-text)" }}>
+                    Warning: MAX of {capturedMax}ms is very fast (&lt;100ms). This could damage the device.
+                  </div>
+                )}
+                {orderWarning && (
+                  <div className="text-xs rounded p-2" style={{ backgroundColor: "var(--danger-bg)", color: "var(--danger-text)" }}>
+                    Warning: Normal ({capturedNormal}ms) is faster than MAX ({capturedMax}ms). Normal should be slower (higher ms). Please re-capture.
+                  </div>
+                )}
+
+                {/* Save messages */}
+                {saveError && (
+                  <div className="text-xs rounded-md p-2 border" style={{ backgroundColor: "var(--danger-bg)", borderColor: "var(--danger)", color: "var(--danger-text)" }}>
+                    {saveError}
+                  </div>
+                )}
+                {saveSuccess && (
+                  <div className="text-xs rounded-md p-2 border" style={{ backgroundColor: "var(--success-bg)", borderColor: "var(--success)", color: "var(--success-text)" }}>
+                    Speeds saved to melody!
+                  </div>
+                )}
               </div>
-            )}
-            {orderWarning && (
-              <div className="text-xs rounded p-2" style={{ backgroundColor: "var(--danger-bg)", color: "var(--danger-text)" }}>
-                Warning: Normal speed ({capturedNormal}ms) is slower than MAX ({capturedMax}ms). Please check your values.
-              </div>
-            )}
+            </div>
           </div>
-
-          {/* Save */}
-          {saveError && (
-            <div className="text-sm rounded-md p-3 border" style={{ backgroundColor: "var(--danger-bg)", borderColor: "var(--danger)", color: "var(--danger-text)" }}>
-              {saveError}
-            </div>
-          )}
-          {saveSuccess && (
-            <div className="text-sm rounded-md p-3 border" style={{ backgroundColor: "var(--success-bg)", borderColor: "var(--success)", color: "var(--success-text)" }}>
-              Speeds saved to melody!
-            </div>
-          )}
         </div>
 
-        <div className="flex items-center justify-end gap-3 px-6 py-4 border-t" style={{ borderColor: "var(--border-primary)" }}>
+        {/* Footer */}
+        <div className="flex items-center justify-end gap-3 px-6 py-4 border-t flex-shrink-0" style={{ borderColor: "var(--border-primary)" }}>
           <button
             onClick={() => { stopPlayback(); onClose(); }}
             className="px-4 py-2 text-sm rounded-md transition-colors"