SPECS: the radio check does not show the analyser cannot hear it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6

.claude/skills/car-logs/SKILL.md

@@ -71,9 +71,17 @@ services by name (2.42.1 on; 2.42.0 also connected to them, which stopped the mu
 session is `com.allgo.remoteui.mediabrowserservice`, Bluetooth's `com.android.bluetooth`. Ask what was playing
 when the check ran.
 
+## Sound checks
+
+`fetch-logs` also brings `sound-probe-YYYYMMDD-HHMMSS.txt` (Logs tab, "Check sound",
+`SoundProbe`, 2.43.3 on): permissions, which session plays, then one line a second of the audio
+analyser's peak, bass, mid, treble and rms, and a result line. Levels only, no sound. The peak has
+to move for music to count as heard. Ask what was playing when the check ran, and whether the
+music kept playing and any prompt came up.
+
 ## Rules
 
 - Recordings and checks are the car's data: `logs/`, `/signal-recording-*.txt` and
-  `/media-probe-*.txt` are gitignored. Never
+  `/media-probe-*.txt`, `/sound-probe-*.txt` are gitignored. Never
   commit, publish or upload them anywhere.
 - Findings that change what the project knows go into a `SPECS.md` done-log entry, as usual.

.gitignore

@@ -46,3 +46,4 @@ mise.local.toml
 /logs/
 /signal-recording-*.txt
 /media-probe-*.txt
+/sound-probe-*.txt

AGENTS.md

@@ -82,7 +82,7 @@ Repository: `ssh://git@git.stinnesbeck.com:2222/nils/mg4.git` (remote `origin`),
 | Live data | on/off, ABRP API key and user token, upload frequency |
 | Server | URL, pairing by QR, ingest token, installation ID (read-only), config import |
 | Settings | drive mode (Eco, Normal, Sport, Snow, Custom; the lit one is what the car reports; changes only in P at a standstill, `DriveModeWrite`; "Set at start" sets the last confirmed choice again when the service starts with the head unit), full screen, voice key, Overview style with the accent colour beside it (offered only for styles drawn in it, `OverviewStyle.usesAccent`; Retro, Terminal, Grid (and Grid with map, sharing Grid's choice) and Visor add "Original" for their own palette, `hasOriginal`), tyre unit, battery and charging price (one card on wide screens), version, update check, install from USB, About |
-| Logs | signal recorder (`SignalRecorder`/`SignalRecording`: every property and vendor getter via `VendorSurfaceProbe.capture`, again and again for 3 minutes, plus change events of the driver-assistance block it subscribes to, `EVHardware.listenToProperties` with `AssistBlock`, and steering-wheel key broadcasts; lists what changed, rarest first; saved to the app, a USB stick and the server, through `LogOutbox`, which sends it again later when the car is offline; how to find where the car publishes something), music-sources check (`MediaProbe`: audio players and the active media sessions, CarPlay's and Bluetooth's among them, with their song, and the media browser services by name — never connected to: binding them stopped the music in 2.42.0; saved and sent like a recording), update log (every install step, with the platform's words), upload log |
+| Logs | signal recorder (`SignalRecorder`/`SignalRecording`: every property and vendor getter via `VendorSurfaceProbe.capture`, again and again for 3 minutes, plus change events of the driver-assistance block it subscribes to, `EVHardware.listenToProperties` with `AssistBlock`, and steering-wheel key broadcasts; lists what changed, rarest first; saved to the app, a USB stick and the server, through `LogOutbox`, which sends it again later when the car is offline; how to find where the car publishes something), music-sources check (`MediaProbe`: audio players and the active media sessions, CarPlay's and Bluetooth's among them, with their song, and the media browser services by name — never connected to: binding them stopped the music in 2.42.0; saved and sent like a recording), sound check (`SoundProbe`, `SoundLevels`: on a tap, 10 seconds of levels from Android's audio analyser, to learn whether it hears what plays; saved and sent like a recording), update log (every install step, with the platform's words), upload log |
 
 Key classes (`app/src/main/java/com/evsuite/abrp/`): `AbrpUploadService` (foreground service,
 15 s tick), `TelemetryUploader` (+ `TelemetryQueue`, persisted), `TelemetryPayload` (server

SPECS.md

@@ -140,6 +140,13 @@ tyre pressures, GPS (lat, lon, elevation, heading) and the is_* flags. It does *
   confirmed car facts, app structure, UI conventions, build/test/ship, documents. It replaces
   upstream's EVABRPUploader text. The test emulator is now in the flake: `nix run .#car-emulator`
   (Android 9 AOSP at 1920×720, 160 dpi; the car build installs as the system user — checked).
+- 2026-10-31 — Music checks from the car: the radio publishes a session while it plays (`com.saicmotor.radio`, 29 October, DAB: TITLE the station, ARTIST the programme text, AUTHOR the band), with `isMusicActive` false; whether the radio could be heard then is not known (the owner did not have it playing in the check they looked at), so this says nothing yet about whether the audio analyser hears it. To be tested with the radio audibly playing. CarPlay playing (31 October, 2.43.2) has `isMusicActive` true, like Bluetooth on 28 October. The sound check itself has not run on the car yet: 2.43.3 was not published and those reports came from 2.43.2's music-sources check.
+- 2026-10-31 — App 2.43.3: **sound check** on the Logs tab (`SoundProbe`, `SoundLevels`), asked for before the Halloween pumpkin's light follows the music (owner: "make the light in the pumpkin react to the equalizer/sound of the music"). One tap: 10 seconds of levels from `Visualizer` on session 0 (peak, bass, mid, treble, rms), saved and sent like a recording; no sound kept, no microphone. New in the car build's manifest: RECORD_AUDIO and MODIFY_AUDIO_SETTINGS. Grounds for trying: Bluetooth played with `isMusicActive` true (28 October check), `libCarPlayPlatformAudio.so` uses AudioTrack and no direct PCM. Whether the analyser hears anything on the car is what this is to find out. Tested: unit tests, lint, emulator (silence says nothing was playing; a pulsing 110 Hz + 1 kHz test tone from another app is heard, peak 0.27–0.91, bass strongest, the tone kept playing, no prompt, no crash). Not tried on the car.
+- 2026-10-31 — App 2.43.2 published (`car-2.43.2`).
+- 2026-10-31 — App 2.43.2: Halloween's teeth are triangles hanging from the grin's upper lip, each in the colour of the rib behind it (the right one was the darker orange on the lighter rib; owner: "the color on the right side is off"). Two screenshots redone. Tested: unit tests, lint, emulator with sample values (drawing in panel and full screen, regenerating in full screen) and with no data. Not tried on the car.
+- 2026-10-31 — App 2.43.1 published (`car-2.43.1`).
+- 2026-10-31 — App 2.43.1: Halloween's bats can be seen. They were near-black and small on the darkest part of the sky, and the owner did not spot them; now a moonlit purple-grey with a light edge, a third larger. Two screenshots redone. Tested: unit tests, lint, emulator with sample values (panel and full screen) and with no data (no bats). Not tried on the car.
+- 2026-10-31 — App 2.43.0 published (`car-2.43.0`).
 - 2026-10-31 — App 2.43.0: Overview styles **Día de Muertos** (`MuertosView`) and **Halloween**
   (`HalloweenView`; owner: "let's design a 'dia de muertos' and a 'halloween' style"), each with
   its own palette (the papel picado's pink, the pumpkin's orange). Día de Muertos, an ofrenda and

app/build.gradle

@@ -34,8 +34,8 @@ android {
         applicationId "com.stinnesbeck.nilsmg4"
         minSdk 27
         targetSdk 36
-        versionCode 153
+        versionCode 156
-        versionName "2.43.0"
+        versionName "2.43.3"
 
         // Nothing about the server ships in the APK: its URL and ingest token are entered in
         // the app's Server tab (ServerConfig), and the database is only reachable by the server.

app/src/main/java/com/evsuite/abrp/HalloweenView.java

@@ -39,6 +39,7 @@ final class HalloweenView extends ClusterCanvasView {
     private static final int STONE_DARK = 0xFF3E3C4A, MOON = 0xFFF4E9B8, MOON_SHADE = 0xFFD8C98C;
     private static final int POTION = 0xFF7BF03A, GLASS = 0xFFB9D8D0, BONE = 0xFFF2EAD8, ORANGE = 0xFFFF8C1A;
     private static final int STEM = 0xFF4E7A2B, WOOD = 0xFF2E1B10, INK = 0xFF140A08;
+    private static final int BAT = 0xFF6F6390, BAT_EDGE = 0xFFD6CCEA;
 
     private final Paint fill = new Paint(Paint.ANTI_ALIAS_FLAG);
     private final Paint line = new Paint(Paint.ANTI_ALIAS_FLAG);
@@ -180,11 +181,11 @@ final class HalloweenView extends ClusterCanvasView {
             float x = ((i * 0.13f * span + time * speed) % span) + w * 0.04f;
             float y = lane + (float) Math.sin(time * 2f + i) * 8f * u;
             if (Math.abs(x - cx) < 60f * u) y -= 10f * u;
-            bat(c, x, y, (i % 2 == 0 ? 15f : 12f) * u, (float) Math.sin(time * 14f + i * 2f));
+            bat(c, x, y, (i % 2 == 0 ? 20f : 16f) * u, (float) Math.sin(time * 14f + i * 2f), u);
         }
     }
 
-    private void bat(Canvas c, float x, float y, float s, float flap) {
+    private void bat(Canvas c, float x, float y, float s, float flap, float u) {
         float tip = -s * 0.5f * flap;
         path.reset();
         path.moveTo(x, y - s * 0.3f);
@@ -197,8 +198,12 @@ final class HalloweenView extends ClusterCanvasView {
         path.quadTo(x - s * 1.1f, y + s * 0.05f, x - s * 1.5f, y - s * 0.3f + tip);
         path.quadTo(x - s * 0.6f, y - s * 0.7f + tip, x, y - s * 0.3f);
         path.close();
-        fill.setColor(0xFF06030C);
+        // Lit by the moon: black would vanish in the night sky.
+        fill.setColor(BAT);
         c.drawPath(path, fill);
+        line.setColor(BAT_EDGE);
+        line.setStrokeWidth(1.5f * u);
+        c.drawPath(path, line);
     }
 
     // ---------- Ghost: only where there is room ----------
@@ -334,10 +339,9 @@ final class HalloweenView extends ClusterCanvasView {
         fill.setColor(burn);
         c.drawPath(path, fill);
         c.restore();
-        // Two teeth at the grin's corners, clear of the digits.
+        // Two teeth at the grin's corners, clear of the digits, each the colour of the rib it hangs from.
-        fill.setColor(PUMPKIN);
+        tooth(c, cx, -120f * u, gw, gt, 26f * u, 17f * u, gt + 40f * u, PUMPKIN, u);
-        tooth(c, cx - 120f * u, gt + 12f * u, 15f * u, 28f * u);
+        tooth(c, cx, 120f * u, gw, gt, 26f * u, 17f * u, gt + 40f * u, PUMPKIN_LIT, u);
-        tooth(c, cx + 120f * u, gt + 12f * u, 15f * u, 28f * u);
         label(c, fmt(v.speedKmh, "%.0f", "—"), cx, gb - 18f * u, 92f * u, INK, serif, Paint.Align.CENTER);
         label(c, "KM/H", cx + 80f * u, cy + 64f * u, 16f * u, INK, face, Paint.Align.LEFT);
         // The power under the pumpkin, above the ridge.
@@ -359,14 +363,27 @@ final class HalloweenView extends ClusterCanvasView {
         c.drawPath(path, line);
     }
 
-    private void tooth(Canvas c, float x, float y, float halfW, float tall) {
+    /** A triangle hanging from the grin's upper lip (a curve sagging by {@code sag}) to {@code tipY}. */
+    private void tooth(Canvas c, float cx, float dx, float gw, float gt, float sag, float halfW, float tipY, int colour, float u) {
+        float left = lip(dx - halfW, gw, gt, sag), right = lip(dx + halfW, gw, gt, sag);
         path.reset();
-        path.moveTo(x - halfW, y - tall * 0.3f);
+        // A little above the lip, so none of its dark edge shows across the tooth's root.
-        path.lineTo(x + halfW, y - tall * 0.3f);
+        path.moveTo(cx + dx - halfW, left - 1.5f * u);
-        path.lineTo(x + halfW, y + tall * 0.7f);
+        path.lineTo(cx + dx + halfW, right - 1.5f * u);
-        path.lineTo(x - halfW, y + tall * 0.7f);
+        path.lineTo(cx + dx, tipY);
         path.close();
+        fill.setColor(colour);
         c.drawPath(path, fill);
+        line.setColor(0xFF4A1F04);
+        line.setStrokeWidth(3f * u);
+        c.drawLine(cx + dx - halfW, left + 2f * u, cx + dx, tipY, line);
+        c.drawLine(cx + dx + halfW, right + 2f * u, cx + dx, tipY, line);
+    }
+
+    /** The height of the grin's upper lip {@code dx} from the middle. */
+    private static float lip(float dx, float gw, float gt, float sag) {
+        float t = (gw - Math.abs(dx)) / (2f * gw);
+        return gt + 2f * t * (1f - t) * sag;
     }
 
     // ---------- Left: the sign under the cobweb ----------

app/src/main/java/com/evsuite/abrp/MainActivity.java

@@ -412,6 +412,10 @@ public class MainActivity extends AppCompatActivity {
             MediaProbe.start(this);
             refreshMediaProbe();
         });
+        logPane.findViewById(R.id.sound_probe_button).setOnClickListener(v -> {
+            SoundProbe.start(this);
+            refreshSoundProbe();
+        });
 
         setUpPager();
         // Back on the page that was open when the activity was recreated (accent colour change).
@@ -2341,9 +2345,20 @@ public class MainActivity extends AppCompatActivity {
         if (!status.isEmpty()) text.setText(String.join("\n", status));
     }
 
+    /** The sound check: its button and its last report. */
+    private void refreshSoundProbe() {
+        MaterialButton button = logPane.findViewById(R.id.sound_probe_button);
+        button.setEnabled(!SoundProbe.running());
+        TextView text = logPane.findViewById(R.id.sound_probe_text);
+        java.util.List<String> status = SoundProbe.status(this);
+        text.setVisibility(status.isEmpty() ? View.GONE : View.VISIBLE);
+        if (!status.isEmpty()) text.setText(String.join("\n", status));
+    }
+
     private void refreshCallLog() {
         refreshSignalRecorder();
         refreshMediaProbe();
+        refreshSoundProbe();
         java.util.List<UploadLog.Entry> entries = AbrpUploadService.log().recent();
         // Update steps first: after a failed install, they are what the driver came here for.
         java.util.List<String> updates = UpdateLog.lines(this);

app/src/main/java/com/evsuite/abrp/SoundLevels.java

@@ -0,0 +1,108 @@
+package com.evsuite.abrp;
+
+import java.util.Locale;
+
+/**
+ * What {@link SoundProbe} makes of Android's audio analyser: how loud a captured waveform is, how
+ * strong a band of its spectrum, and whether a run of those looks like music the analyser can
+ * hear. A failed read is null, never a silent 0. Android-free and unit-tested.
+ */
+final class SoundLevels {
+
+    /** Below this the peak counts as silence (the 8-bit waveform's noise is about 1/128). */
+    static final float SILENT = 0.02f;
+
+    private SoundLevels() {}
+
+    /** The waveform's peak from 0 to 1. Its samples are unsigned 8-bit, with silence at 128. */
+    static Float peak(byte[] wave) {
+        if (wave == null || wave.length == 0) return null;
+        int max = 0;
+        for (byte b : wave) max = Math.max(max, Math.abs((b & 0xFF) - 128));
+        return Math.min(1f, max / 128f);
+    }
+
+    /**
+     * The mean strength from 0 to 1 of the bins between {@code fromHz} and {@code toHz}. The
+     * analyser's FFT holds the DC and Nyquist values first, then each bin's real and imaginary
+     * part, signed; a bin {@code k} is {@code k × rate / length} Hz.
+     */
+    static Float band(byte[] fft, int rateHz, float fromHz, float toHz) {
+        if (fft == null || fft.length < 4 || rateHz <= 0) return null;
+        float sum = 0f;
+        int bins = 0;
+        for (int k = 1; k < fft.length / 2; k++) {
+            float hz = k * (float) rateHz / fft.length;
+            if (hz < fromHz || hz >= toHz) continue;
+            sum += (float) Math.hypot(fft[2 * k], fft[2 * k + 1]) / 128f;
+            bins++;
+        }
+        return bins == 0 ? null : Math.min(1f, sum / bins);
+    }
+
+    enum Verdict {
+        /** The analyser gave no readings at all. */
+        NO_READING,
+        /** Nothing was playing and the analyser heard nothing: says nothing about the source. */
+        NOTHING_PLAYING,
+        /** Something played and the analyser heard silence: it cannot hear this source. */
+        DEAF,
+        /** The level stays where it is: not music, or not real data. */
+        STEADY,
+        /** The level moves: the pumpkin could follow it. */
+        HEARS
+    }
+
+    /** Readings gathered over a time. */
+    static final class Summary {
+        private int samples, readings, bandReadings;
+        private float peakMin = Float.MAX_VALUE, peakMax, bass, mid, treble;
+        private Integer rms;
+
+        /** One round of reads, each null when it failed. */
+        void add(Float peak, Float bassBand, Float midBand, Float trebleBand, Integer rmsMilliBel) {
+            samples++;
+            if (peak != null) {
+                readings++;
+                peakMin = Math.min(peakMin, peak);
+                peakMax = Math.max(peakMax, peak);
+            }
+            if (bassBand != null && midBand != null && trebleBand != null) {
+                bandReadings++;
+                bass += bassBand;
+                mid += midBand;
+                treble += trebleBand;
+            }
+            if (rmsMilliBel != null) rms = rmsMilliBel;
+        }
+
+        Verdict verdict(boolean somethingPlays) {
+            if (readings == 0) return Verdict.NO_READING;
+            if (peakMax < SILENT) return somethingPlays ? Verdict.DEAF : Verdict.NOTHING_PLAYING;
+            return peakMax - peakMin < SILENT ? Verdict.STEADY : Verdict.HEARS;
+        }
+
+        /** One line of the report; what could not be read is "—". */
+        String line() {
+            return "peak " + (readings == 0 ? "—" : String.format(Locale.US, "%.2f–%.2f", peakMin, peakMax))
+                    + ", bass " + mean(bass) + ", mid " + mean(mid) + ", treble " + mean(treble)
+                    + ", rms " + (rms == null ? "—" : rms + " mB")
+                    + " (" + readings + "/" + samples + ")";
+        }
+
+        private String mean(float sum) {
+            return bandReadings == 0 ? "—" : String.format(Locale.US, "%.3f", sum / bandReadings);
+        }
+    }
+
+    /** The report's last line. */
+    static String words(Verdict verdict) {
+        switch (verdict) {
+            case HEARS: return "Result: the analyser hears it, and the level moves.";
+            case STEADY: return "Result: the level does not move, so this is not usable music.";
+            case DEAF: return "Result: something plays, but the analyser hears silence.";
+            case NOTHING_PLAYING: return "Result: nothing was playing, so this says nothing. Play something and check again.";
+            default: return "Result: the analyser gave no readings.";
+        }
+    }
+}

app/src/main/java/com/evsuite/abrp/SoundProbe.java

@@ -0,0 +1,179 @@
+package com.evsuite.abrp;
+
+import android.Manifest;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.media.AudioManager;
+import android.media.audiofx.Visualizer;
+import android.media.session.MediaController;
+import android.media.session.MediaSessionManager;
+import android.media.session.PlaybackState;
+
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * The sound check on the Logs tab: whether Android's audio analyser ({@link Visualizer} on the
+ * output mix, session 0) can hear what the head unit plays, before the Halloween pumpkin's light
+ * follows the music. Only one tap starts it, and it listens for {@value #SECONDS} seconds and lets
+ * go. It records levels only, never the sound, and uses no microphone. The report goes where a
+ * signal recording goes ({@link SignalRecorder#saveCopies}): the app, a USB stick, the server.
+ */
+final class SoundProbe {
+
+    static final String FILE = "sound_probe.txt";
+    private static final int SECONDS = 10, READS_PER_SECOND = 10;
+
+    private static volatile boolean running;
+    private static long startedMs;
+    private static List<String> report = new ArrayList<>();
+    private static String result;
+
+    private SoundProbe() {}
+
+    static synchronized boolean running() {
+        return running;
+    }
+
+    static synchronized void start(Context context) {
+        if (running) return;
+        Context app = context.getApplicationContext();
+        running = true;
+        startedMs = System.currentTimeMillis();
+        result = null;
+        report = new ArrayList<>();
+        new Thread(() -> probe(app), "sound-probe").start();
+    }
+
+    private static void probe(Context app) {
+        List<String> out = new ArrayList<>();
+        out.add("Sound probe, " + SignalRecording.time(startedMs) + ", app " + BuildConfig.VERSION_NAME);
+        String saved;
+        try {
+            permission(app, Manifest.permission.RECORD_AUDIO, out);
+            permission(app, Manifest.permission.MODIFY_AUDIO_SETTINGS, out);
+            boolean plays = sessions(app, out);
+            plays |= musicActive(app, out);
+            SoundLevels.Summary all = listen(out);
+            plays |= musicActive(app, out);
+            out.add("");
+            out.add(SoundLevels.words(all.verdict(plays)));
+        } catch (Throwable t) {
+            out.add("probe stopped: " + t.getClass().getSimpleName());
+        } finally {
+            String name = "sound-probe-" + new SimpleDateFormat("yyyyMMdd-HHmmss", Locale.US)
+                    .format(new Date(startedMs)) + ".txt";
+            saved = SignalRecorder.saveCopies(app, FILE, name, out);
+            synchronized (SoundProbe.class) {
+                report = out;
+                result = saved;
+                running = false;
+            }
+        }
+    }
+
+    private static void permission(Context app, String name, List<String> out) {
+        boolean granted = app.checkSelfPermission(name) == PackageManager.PERMISSION_GRANTED;
+        out.add(name.substring(name.lastIndexOf('.') + 1) + ": " + (granted ? "granted" : "not granted"));
+    }
+
+    private static boolean musicActive(Context app, List<String> out) {
+        try {
+            AudioManager am = (AudioManager) app.getSystemService(Context.AUDIO_SERVICE);
+            boolean active = am != null && am.isMusicActive();
+            out.add("music active: " + active);
+            return active;
+        } catch (RuntimeException e) {
+            out.add("music active: unreadable (" + e.getClass().getSimpleName() + ")");
+            return false;
+        }
+    }
+
+    /** Which source is playing, for reading the report later; no song. True when one is. */
+    private static boolean sessions(Context app, List<String> out) {
+        boolean playing = false;
+        try {
+            MediaSessionManager msm = (MediaSessionManager) app.getSystemService(Context.MEDIA_SESSION_SERVICE);
+            List<MediaController> controllers = msm == null ? null : msm.getActiveSessions(null);
+            if (controllers == null || controllers.isEmpty()) out.add("sessions: none");
+            else for (MediaController c : controllers) {
+                PlaybackState s = c.getPlaybackState();
+                out.add("session: " + MediaProbeText.clean(c.getPackageName()) + ", "
+                        + (s == null ? "no state" : MediaProbeText.playbackState(s.getState())));
+                if (s != null && s.getState() == PlaybackState.STATE_PLAYING) playing = true;
+            }
+        } catch (Throwable t) {
+            out.add("sessions: not readable (" + t.getClass().getSimpleName() + ")");
+        }
+        return playing;
+    }
+
+    /** Listens for the whole time, one report line a second; always lets the analyser go. */
+    private static SoundLevels.Summary listen(List<String> out) throws InterruptedException {
+        SoundLevels.Summary all = new SoundLevels.Summary();
+        Visualizer analyser = null;
+        try {
+            analyser = new Visualizer(0);
+            int[] sizes = Visualizer.getCaptureSizeRange();
+            int code = analyser.setCaptureSize(sizes[1]);
+            analyser.setScalingMode(Visualizer.SCALING_MODE_NORMALIZED);
+            analyser.setMeasurementMode(Visualizer.MEASUREMENT_MODE_PEAK_RMS);
+            int enabled = analyser.setEnabled(true);
+            int size = analyser.getCaptureSize(), rateHz = analyser.getSamplingRate() / 1000;
+            out.add("analyser: capture " + size + " at " + rateHz + " Hz, set size " + code + ", enable " + enabled);
+            if (enabled != Visualizer.SUCCESS) return all;
+            byte[] wave = new byte[size], fft = new byte[size];
+            Visualizer.MeasurementPeakRms measure = new Visualizer.MeasurementPeakRms();
+            for (int second = 0; second < SECONDS; second++) {
+                SoundLevels.Summary now = new SoundLevels.Summary();
+                for (int read = 0; read < READS_PER_SECOND; read++) {
+                    Thread.sleep(1000 / READS_PER_SECOND);
+                    Float peak = analyser.getWaveForm(wave) == Visualizer.SUCCESS ? SoundLevels.peak(wave) : null;
+                    boolean spectrum = analyser.getFft(fft) == Visualizer.SUCCESS;
+                    Float bass = spectrum ? SoundLevels.band(fft, rateHz, 20f, 250f) : null;
+                    Float mid = spectrum ? SoundLevels.band(fft, rateHz, 250f, 2000f) : null;
+                    Float treble = spectrum ? SoundLevels.band(fft, rateHz, 2000f, 16000f) : null;
+                    Integer rms = analyser.getMeasurementPeakRms(measure) == Visualizer.SUCCESS ? measure.mRms : null;
+                    now.add(peak, bass, mid, treble, rms);
+                    all.add(peak, bass, mid, treble, rms);
+                }
+                out.add(MediaProbeText.duration(second * 1000L) + "  " + now.line());
+            }
+        } catch (RuntimeException e) {
+            out.add("analyser not available: " + e.getClass().getSimpleName() + " " + MediaProbeText.clean(e.getMessage()));
+        } finally {
+            if (analyser != null) {
+                try {
+                    analyser.setEnabled(false);
+                } catch (RuntimeException ignored) {
+                    // Released next either way.
+                }
+                try {
+                    analyser.release();
+                } catch (RuntimeException e) {
+                    out.add("analyser not released: " + e.getClass().getSimpleName());
+                }
+            }
+        }
+        return all;
+    }
+
+    /** What the Logs tab shows: the state, then the report. */
+    static synchronized List<String> status(Context context) {
+        List<String> lines = new ArrayList<>();
+        if (startedMs == 0) return lines;
+        if (running) {
+            lines.add(context.getString(R.string.sound_probe_running));
+            return lines;
+        }
+        lines.add(context.getString(R.string.media_probe_done, SignalRecording.time(startedMs),
+                result == null ? "…" : result));
+        String sent = LogOutbox.status(context);
+        if (sent != null) lines.add(sent);
+        lines.addAll(report.subList(Math.min(1, report.size()), report.size()));
+        return lines;
+    }
+}

app/src/main/res/layout/pane_log.xml

@@ -15,6 +15,13 @@
             <com.google.android.material.button.MaterialButton android:id="@+id/media_probe_button" android:layout_width="match_parent" android:layout_height="72dp" android:layout_marginTop="16dp" android:text="@string/btn_media_probe" style="@style/Widget.EV.Button.Outlined" />
             <TextView android:id="@+id/media_probe_text" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:textAppearance="@style/Text.EV.Body" android:fontFamily="monospace" android:textSize="17sp" android:lineSpacingExtra="8dp" android:textIsSelectable="true" android:visibility="gone" />
         </LinearLayout>
+        <!-- The sound check (SoundProbe): whether the audio analyser can hear what plays. -->
+        <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:paddingStart="24dp" android:paddingEnd="24dp" android:paddingTop="16dp" android:paddingBottom="16dp" android:layout_marginBottom="16dp" android:background="@drawable/bg_glass">
+            <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/label_sound_probe" android:textAppearance="@style/Text.EV.Eyebrow" />
+            <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="12dp" android:text="@string/sound_probe_hint" android:textAppearance="@style/Text.EV.Secondary" />
+            <com.google.android.material.button.MaterialButton android:id="@+id/sound_probe_button" android:layout_width="match_parent" android:layout_height="72dp" android:layout_marginTop="16dp" android:text="@string/btn_sound_probe" style="@style/Widget.EV.Button.Outlined" />
+            <TextView android:id="@+id/sound_probe_text" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:textAppearance="@style/Text.EV.Body" android:fontFamily="monospace" android:textSize="17sp" android:lineSpacingExtra="8dp" android:textIsSelectable="true" android:visibility="gone" />
+        </LinearLayout>
         <LinearLayout android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical" android:paddingStart="24dp" android:paddingEnd="24dp" android:paddingTop="16dp" android:paddingBottom="16dp" android:background="@drawable/bg_glass">
             <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:text="@string/label_call_log" android:textAppearance="@style/Text.EV.Eyebrow" />
             <com.google.android.material.button.MaterialButton android:id="@+id/flush_now_button" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:text="@string/btn_flush_now" app:icon="@drawable/ic_refresh" app:iconGravity="textStart" style="@style/Widget.EV.Button.Outlined" />

app/src/main/res/values/strings.xml

@@ -233,6 +233,10 @@
     <string name="label_media_probe">Music sources</string>
     <string name="media_probe_hint">Finds where the head unit tells what is playing: the playback Android reports and the media sessions apps publish (CarPlay, Bluetooth, radio, USB), each with its song, and the head unit\'s media services by name. Play something first and check once for each source. Like a recording, the result goes to your server and to a USB stick. It only reads and connects to no other app: nothing is played, paused or skipped.</string>
     <string name="btn_media_probe">Check music sources</string>
+    <string name="label_sound_probe">Sound check</string>
+    <string name="sound_probe_hint">Finds out whether the app can hear the music, for a light that follows it. Park first, play something, then check once each for Bluetooth, CarPlay and radio. It listens for 10 seconds and keeps only the levels, never the sound, and uses no microphone. Like a recording, the result goes to your server and to a USB stick.</string>
+    <string name="btn_sound_probe">Check sound</string>
+    <string name="sound_probe_running">Listening… (10 seconds)</string>
     <string name="media_probe_running">Checking… (up to a minute)</string>
     <string name="media_probe_done">Check from %1$s, %2$s:</string>
     <string name="log_outbox_sent">Sent to the server.</string>

app/src/test/java/com/evsuite/abrp/SoundLevelsTest.java

@@ -0,0 +1,78 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+import org.junit.Test;
+
+public class SoundLevelsTest {
+
+    private static byte[] wave(int... unsigned) {
+        byte[] out = new byte[unsigned.length];
+        for (int i = 0; i < out.length; i++) out[i] = (byte) unsigned[i];
+        return out;
+    }
+
+    @Test
+    public void silenceIsTheMiddleOfTheWaveform() {
+        assertEquals(0f, SoundLevels.peak(wave(128, 128, 128)), 0f);
+        assertEquals(0.5f, SoundLevels.peak(wave(128, 192, 128)), 0f);
+        assertEquals(0.5f, SoundLevels.peak(wave(128, 64, 128)), 0f);
+        assertEquals(1f, SoundLevels.peak(wave(0, 255)), 0f);
+    }
+
+    @Test
+    public void aFailedReadIsNotSilence() {
+        assertNull(SoundLevels.peak(null));
+        assertNull(SoundLevels.peak(new byte[0]));
+        assertNull(SoundLevels.band(null, 48000, 0f, 250f));
+        assertNull(SoundLevels.band(new byte[8], 0, 0f, 250f));
+    }
+
+    @Test
+    public void aBandAveragesItsOwnBins() {
+        // Eight values: DC and Nyquist, then bins 1 to 3, here 1000, 2000 and 3000 Hz.
+        byte[] fft = { 99, 99, 64, 0, 0, 32, 3, 4 };
+        assertEquals(0.5f, SoundLevels.band(fft, 8000, 500f, 1500f), 1e-6f);
+        assertEquals(0.25f, SoundLevels.band(fft, 8000, 2000f, 2500f), 1e-6f);
+        assertEquals(5f / 128f, SoundLevels.band(fft, 8000, 3000f, 4000f), 1e-6f);
+        assertEquals((0.5f + 0.25f) / 2f, SoundLevels.band(fft, 8000, 500f, 2500f), 1e-6f);
+        assertNull(SoundLevels.band(fft, 8000, 5000f, 6000f));
+    }
+
+    @Test
+    public void theVerdictTellsDeafFromNothingPlaying() {
+        SoundLevels.Summary none = new SoundLevels.Summary();
+        none.add(null, null, null, null, null);
+        assertEquals(SoundLevels.Verdict.NO_READING, none.verdict(true));
+
+        SoundLevels.Summary silent = new SoundLevels.Summary();
+        silent.add(0f, 0f, 0f, 0f, -9600);
+        silent.add(0.01f, 0f, 0f, 0f, -9600);
+        assertEquals(SoundLevels.Verdict.DEAF, silent.verdict(true));
+        assertEquals(SoundLevels.Verdict.NOTHING_PLAYING, silent.verdict(false));
+    }
+
+    @Test
+    public void onlyAMovingLevelIsHeard() {
+        SoundLevels.Summary steady = new SoundLevels.Summary();
+        steady.add(0.4f, 0.1f, 0.1f, 0.1f, -2000);
+        steady.add(0.41f, 0.1f, 0.1f, 0.1f, -2000);
+        assertEquals(SoundLevels.Verdict.STEADY, steady.verdict(true));
+
+        SoundLevels.Summary music = new SoundLevels.Summary();
+        music.add(0.1f, 0.2f, 0.1f, 0f, -3000);
+        music.add(0.6f, 0.4f, 0.3f, 0.1f, -1500);
+        assertEquals(SoundLevels.Verdict.HEARS, music.verdict(true));
+    }
+
+    @Test
+    public void theLineAveragesAndMarksWhatFailed() {
+        SoundLevels.Summary s = new SoundLevels.Summary();
+        s.add(0.1f, 0.2f, 0.1f, 0f, -3000);
+        s.add(null, null, null, null, null);
+        s.add(0.6f, 0.4f, 0.3f, 0.1f, -1500);
+        assertEquals("peak 0.10–0.60, bass 0.300, mid 0.200, treble 0.050, rms -1500 mB (2/3)", s.line());
+        assertEquals("peak —, bass —, mid —, treble —, rms — (0/0)", new SoundLevels.Summary().line());
+    }
+}

app/src/unstable/AndroidManifest.xml

@@ -18,6 +18,11 @@
         android:name="android.permission.MEDIA_CONTENT_CONTROL"
         tools:ignore="ProtectedPermissions" />
 
+    <!-- The Logs tab's sound check (SoundProbe): Android's audio analyser asks for both. The
+         system user holds them without a prompt; the analyser reports levels only, no sound. -->
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
+    <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
+
     <application>
         <provider
             android:name="androidx.core.content.FileProvider"