diff --git a/targets/app/meson.build b/targets/app/meson.build
index 6641edc3f..6f90b86e7 100644
--- a/targets/app/meson.build
+++ b/targets/app/meson.build
@@ -16,6 +16,7 @@ client_dependencies = [
   profile_dep,
   storage_dep,
   fs_dep,
+  sound_dep,
   assets_localisation_dep,
   platform_dep,
   minecraft_dep,
diff --git a/targets/minecraft/meson.build b/targets/minecraft/meson.build
index 2de8cc71a..dfa8b95b6 100644
--- a/targets/minecraft/meson.build
+++ b/targets/minecraft/meson.build
@@ -23,7 +23,7 @@ endif
 lib_minecraft = static_library('minecraft',
   minecraft_sources,
   dependencies : [
-    miniaudio_dep, # TODO: remove once a SoundEngine facade is present
+    sound_dep,
     render_dep,
     input_dep,
     profile_dep,
diff --git a/targets/platform/meson.build b/targets/platform/meson.build
index a52dc8255..f8ab4cd4c 100644
--- a/targets/platform/meson.build
+++ b/targets/platform/meson.build
@@ -31,3 +31,4 @@ subdir('profile')
 subdir('storage')
 subdir('fs')
 subdir('renderer')
+subdir('sound')
diff --git a/targets/platform/sound/IPlatformSound.h b/targets/platform/sound/IPlatformSound.h
new file mode 100644
index 000000000..7541dc967
--- /dev/null
+++ b/targets/platform/sound/IPlatformSound.h
@@ -0,0 +1,101 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+#include "platform/sound/SoundHandles.h"
+
+// Platform sound interface. The backend (currently miniaudio) implements
+// this; consumers in app/common/Audio/SoundEngine talk to the interface
+// rather than to miniaudio directly.
+//
+// The interface is intent-level: load a sample from disk, play it,
+// stop it, set listener position. State (volume, pitch, looping) is
+// passed at play time as a struct rather than via global setters.
+//
+// Concrete handles (SoundHandle, MusicHandle) are tagged structs so the
+// type system catches sample-vs-music confusion at compile time.
+
+namespace platform::sound {
+
+struct PlaySoundParams {
+    float x = 0.0f;
+    float y = 0.0f;
+    float z = 0.0f;
+    float volume = 1.0f;
+    float pitch = 1.0f;
+    bool spatial = true;       // 3D sound positioned in the world
+    bool looping = false;
+    float minDistance = 1.0f;  // distance below which the sound is full-volume
+    float maxDistance = 16.0f; // distance above which the sound is silent
+};
+
+struct PlayMusicParams {
+    float volume = 1.0f;
+    float pitch = 1.0f;
+    bool looping = false;
+};
+
+class IPlatformSound {
+public:
+    virtual ~IPlatformSound() = default;
+
+    // Lifecycle. init() takes the maximum number of simultaneous local
+    // listeners (splitscreen player count). Idempotent: a second init()
+    // call with the same parameters is a no-op.
+    virtual void init(int listenerCount) = 0;
+    virtual void shutdown() = 0;
+
+    // Per-frame tick. Drives streaming reads, voice cleanup, etc.
+    virtual void tick() = 0;
+
+    // Master volume scaling. 0.0 to 1.0. Applies to all subsequent
+    // sound and music playback.
+    virtual void setMasterVolume(float volume) = 0;
+
+    // -- Spatial / one-shot sound effects --
+
+    // Load and start playing a sound. The backend allocates a voice and
+    // returns a handle that can be used to query / stop the sound. If
+    // the load fails or the mixer is at capacity, returns an invalid
+    // handle (the caller should treat that as "sound was dropped" - not
+    // an error).
+    [[nodiscard]] virtual SoundHandle playSoundFromFile(
+        const std::string& path, const PlaySoundParams& params) = 0;
+
+    virtual void stopSound(SoundHandle handle) = 0;
+    [[nodiscard]] virtual bool isSoundPlaying(SoundHandle handle) const = 0;
+
+    virtual void setSoundVolume(SoundHandle handle, float volume) = 0;
+    virtual void setSoundPosition(SoundHandle handle, float x, float y,
+                                  float z) = 0;
+    virtual void setSoundPitch(SoundHandle handle, float pitch) = 0;
+
+    // Release the voice. Idempotent on invalid handles.
+    virtual void releaseSound(SoundHandle handle) = 0;
+
+    // -- Streaming music --
+
+    // Load and start a streaming music track. Streaming means the
+    // backend reads the file incrementally rather than decoding it all
+    // upfront. Use for music tracks; sound effects should use the
+    // playSound* methods above.
+    [[nodiscard]] virtual MusicHandle playMusicFromFile(
+        const std::string& path, const PlayMusicParams& params) = 0;
+
+    virtual void stopMusic(MusicHandle handle) = 0;
+    [[nodiscard]] virtual bool isMusicPlaying(MusicHandle handle) const = 0;
+    virtual void setMusicVolume(MusicHandle handle, float volume) = 0;
+    virtual void setMusicPitch(MusicHandle handle, float pitch) = 0;
+    virtual void releaseMusic(MusicHandle handle) = 0;
+
+    // -- Listener (one per local splitscreen player) --
+
+    virtual void setListenerPosition(int listenerIndex, float x, float y,
+                                     float z) = 0;
+    virtual void setListenerOrientation(int listenerIndex, float forwardX,
+                                        float forwardY, float forwardZ,
+                                        float upX, float upY, float upZ) = 0;
+};
+
+}  // namespace platform::sound
diff --git a/targets/platform/sound/SoundHandles.h b/targets/platform/sound/SoundHandles.h
new file mode 100644
index 000000000..16a856df1
--- /dev/null
+++ b/targets/platform/sound/SoundHandles.h
@@ -0,0 +1,30 @@
+#pragma once
+
+#include <cstdint>
+
+// Type-safe handles for the platform sound subsystem. Each handle is a
+// tagged 32-bit integer; the tag struct prevents accidental conversion
+// between handle types at compile time.
+//
+// Handle 0 is reserved for "invalid". Backends should never return 0
+// from a successful create call.
+
+namespace platform::sound {
+
+template <class Tag>
+struct Handle {
+    std::uint32_t id = 0;
+
+    [[nodiscard]] constexpr bool valid() const noexcept { return id != 0; }
+    constexpr explicit operator bool() const noexcept { return valid(); }
+
+    friend constexpr bool operator==(Handle, Handle) = default;
+};
+
+struct SoundTag {};
+struct MusicTag {};
+
+using SoundHandle = Handle<SoundTag>;
+using MusicHandle = Handle<MusicTag>;
+
+}  // namespace platform::sound
diff --git a/targets/platform/sound/meson.build b/targets/platform/sound/meson.build
new file mode 100644
index 000000000..79f6f4519
--- /dev/null
+++ b/targets/platform/sound/meson.build
@@ -0,0 +1,15 @@
+_miniaudio_dep = dependency('miniaudio')
+
+lib_platform_sound_miniaudio = static_library(
+  'platform_sound_miniaudio',
+  files('miniaudio/MiniaudioSound.cpp'),
+  include_directories: [platform_inc, include_directories('../..')],
+  dependencies: [_threads, _miniaudio_dep],
+  cpp_args: global_cpp_args + global_cpp_defs,
+)
+
+sound_dep = declare_dependency(
+  link_with: lib_platform_sound_miniaudio,
+  include_directories: [platform_inc],
+  dependencies: [_miniaudio_dep],
+)
diff --git a/targets/platform/sound/miniaudio/MiniaudioSound.cpp b/targets/platform/sound/miniaudio/MiniaudioSound.cpp
new file mode 100644
index 000000000..5aa8c3424
--- /dev/null
+++ b/targets/platform/sound/miniaudio/MiniaudioSound.cpp
@@ -0,0 +1,261 @@
+#include "MiniaudioSound.h"
+
+#include <atomic>
+#include <unordered_map>
+
+#include "miniaudio.h"
+
+#include "platform/sound/sound.h"
+
+namespace platform::sound::miniaudio {
+
+namespace {
+
+// Each loaded sound voice. Owned by the State's map; the SoundHandle
+// the caller holds is the integer key.
+struct Voice {
+    ma_sound sound{};
+    bool inUse = false;
+};
+
+}  // namespace
+
+struct State {
+    ma_engine engine{};
+    ma_engine_config engineConfig{};
+    bool engineReady = false;
+
+    // Voice pool. Sound handles are keys; the backend allocates a fresh
+    // id for every play call. Caller releases via releaseSound() (or
+    // we'll auto-release when the sound finishes - tick() handles that).
+    std::unordered_map<std::uint32_t, std::unique_ptr<Voice>> sounds;
+    std::unordered_map<std::uint32_t, std::unique_ptr<Voice>> music;
+    std::atomic<std::uint32_t> nextHandleId{1};
+};
+
+MiniaudioSound::MiniaudioSound() : m_state(std::make_unique<State>()) {}
+MiniaudioSound::~MiniaudioSound() {
+    if (m_state && m_state->engineReady) {
+        shutdown();
+    }
+}
+MiniaudioSound::MiniaudioSound(MiniaudioSound&&) noexcept = default;
+MiniaudioSound& MiniaudioSound::operator=(MiniaudioSound&&) noexcept = default;
+
+void MiniaudioSound::init(int listenerCount) {
+    if (m_state->engineReady) return;
+    m_state->engineConfig = ma_engine_config_init();
+    m_state->engineConfig.listenerCount =
+        listenerCount > 0 ? static_cast<ma_uint32>(listenerCount) : 1;
+    if (ma_engine_init(&m_state->engineConfig, &m_state->engine) !=
+        MA_SUCCESS) {
+        return;
+    }
+    ma_engine_set_volume(&m_state->engine, 1.0f);
+    m_state->engineReady = true;
+}
+
+void MiniaudioSound::shutdown() {
+    if (!m_state->engineReady) return;
+    // Tear down all live voices first.
+    for (auto& [id, voice] : m_state->sounds) {
+        if (voice && voice->inUse) {
+            ma_sound_uninit(&voice->sound);
+        }
+    }
+    m_state->sounds.clear();
+    for (auto& [id, voice] : m_state->music) {
+        if (voice && voice->inUse) {
+            ma_sound_uninit(&voice->sound);
+        }
+    }
+    m_state->music.clear();
+    ma_engine_uninit(&m_state->engine);
+    m_state->engineReady = false;
+}
+
+void MiniaudioSound::tick() {
+    if (!m_state->engineReady) return;
+    // Reap finished one-shot sounds (non-looping, not currently playing).
+    // We don't auto-reap music here; music is explicitly stopped by the
+    // game's music system.
+    for (auto it = m_state->sounds.begin(); it != m_state->sounds.end();) {
+        auto& voice = it->second;
+        if (voice && voice->inUse &&
+            !ma_sound_is_playing(&voice->sound) &&
+            !ma_sound_is_looping(&voice->sound)) {
+            ma_sound_uninit(&voice->sound);
+            voice->inUse = false;
+            it = m_state->sounds.erase(it);
+        } else {
+            ++it;
+        }
+    }
+}
+
+void MiniaudioSound::setMasterVolume(float volume) {
+    if (!m_state->engineReady) return;
+    ma_engine_set_volume(&m_state->engine, volume);
+}
+
+SoundHandle MiniaudioSound::playSoundFromFile(const std::string& path,
+                                              const PlaySoundParams& params) {
+    if (!m_state->engineReady) return {};
+    auto voice = std::make_unique<Voice>();
+    if (ma_sound_init_from_file(&m_state->engine, path.c_str(),
+                                MA_SOUND_FLAG_ASYNC, nullptr, nullptr,
+                                &voice->sound) != MA_SUCCESS) {
+        return {};
+    }
+    ma_sound_set_spatialization_enabled(&voice->sound,
+                                        params.spatial ? MA_TRUE : MA_FALSE);
+    ma_sound_set_min_distance(&voice->sound, params.minDistance);
+    ma_sound_set_max_distance(&voice->sound, params.maxDistance);
+    ma_sound_set_volume(&voice->sound, params.volume);
+    ma_sound_set_pitch(&voice->sound, params.pitch);
+    ma_sound_set_position(&voice->sound, params.x, params.y, params.z);
+    ma_sound_set_looping(&voice->sound, params.looping ? MA_TRUE : MA_FALSE);
+    ma_sound_start(&voice->sound);
+    voice->inUse = true;
+
+    SoundHandle handle{m_state->nextHandleId.fetch_add(1)};
+    m_state->sounds.emplace(handle.id, std::move(voice));
+    return handle;
+}
+
+void MiniaudioSound::stopSound(SoundHandle handle) {
+    auto it = m_state->sounds.find(handle.id);
+    if (it == m_state->sounds.end() || !it->second) return;
+    if (it->second->inUse) {
+        ma_sound_stop(&it->second->sound);
+    }
+}
+
+bool MiniaudioSound::isSoundPlaying(SoundHandle handle) const {
+    auto it = m_state->sounds.find(handle.id);
+    if (it == m_state->sounds.end() || !it->second || !it->second->inUse) {
+        return false;
+    }
+    return ma_sound_is_playing(&it->second->sound) != MA_FALSE;
+}
+
+void MiniaudioSound::setSoundVolume(SoundHandle handle, float volume) {
+    auto it = m_state->sounds.find(handle.id);
+    if (it == m_state->sounds.end() || !it->second || !it->second->inUse)
+        return;
+    ma_sound_set_volume(&it->second->sound, volume);
+}
+
+void MiniaudioSound::setSoundPosition(SoundHandle handle, float x, float y,
+                                      float z) {
+    auto it = m_state->sounds.find(handle.id);
+    if (it == m_state->sounds.end() || !it->second || !it->second->inUse)
+        return;
+    ma_sound_set_position(&it->second->sound, x, y, z);
+}
+
+void MiniaudioSound::setSoundPitch(SoundHandle handle, float pitch) {
+    auto it = m_state->sounds.find(handle.id);
+    if (it == m_state->sounds.end() || !it->second || !it->second->inUse)
+        return;
+    ma_sound_set_pitch(&it->second->sound, pitch);
+}
+
+void MiniaudioSound::releaseSound(SoundHandle handle) {
+    auto it = m_state->sounds.find(handle.id);
+    if (it == m_state->sounds.end()) return;
+    if (it->second && it->second->inUse) {
+        ma_sound_uninit(&it->second->sound);
+        it->second->inUse = false;
+    }
+    m_state->sounds.erase(it);
+}
+
+MusicHandle MiniaudioSound::playMusicFromFile(const std::string& path,
+                                              const PlayMusicParams& params) {
+    if (!m_state->engineReady) return {};
+    auto voice = std::make_unique<Voice>();
+    if (ma_sound_init_from_file(&m_state->engine, path.c_str(),
+                                MA_SOUND_FLAG_STREAM, nullptr, nullptr,
+                                &voice->sound) != MA_SUCCESS) {
+        return {};
+    }
+    ma_sound_set_spatialization_enabled(&voice->sound, MA_FALSE);
+    ma_sound_set_volume(&voice->sound, params.volume);
+    ma_sound_set_pitch(&voice->sound, params.pitch);
+    ma_sound_set_looping(&voice->sound, params.looping ? MA_TRUE : MA_FALSE);
+    ma_sound_start(&voice->sound);
+    voice->inUse = true;
+
+    MusicHandle handle{m_state->nextHandleId.fetch_add(1)};
+    m_state->music.emplace(handle.id, std::move(voice));
+    return handle;
+}
+
+void MiniaudioSound::stopMusic(MusicHandle handle) {
+    auto it = m_state->music.find(handle.id);
+    if (it == m_state->music.end() || !it->second) return;
+    if (it->second->inUse) {
+        ma_sound_stop(&it->second->sound);
+    }
+}
+
+bool MiniaudioSound::isMusicPlaying(MusicHandle handle) const {
+    auto it = m_state->music.find(handle.id);
+    if (it == m_state->music.end() || !it->second || !it->second->inUse)
+        return false;
+    return ma_sound_is_playing(&it->second->sound) != MA_FALSE;
+}
+
+void MiniaudioSound::setMusicVolume(MusicHandle handle, float volume) {
+    auto it = m_state->music.find(handle.id);
+    if (it == m_state->music.end() || !it->second || !it->second->inUse)
+        return;
+    ma_sound_set_volume(&it->second->sound, volume);
+}
+
+void MiniaudioSound::setMusicPitch(MusicHandle handle, float pitch) {
+    auto it = m_state->music.find(handle.id);
+    if (it == m_state->music.end() || !it->second || !it->second->inUse)
+        return;
+    ma_sound_set_pitch(&it->second->sound, pitch);
+}
+
+void MiniaudioSound::releaseMusic(MusicHandle handle) {
+    auto it = m_state->music.find(handle.id);
+    if (it == m_state->music.end()) return;
+    if (it->second && it->second->inUse) {
+        ma_sound_uninit(&it->second->sound);
+        it->second->inUse = false;
+    }
+    m_state->music.erase(it);
+}
+
+void MiniaudioSound::setListenerPosition(int listenerIndex, float x, float y,
+                                         float z) {
+    if (!m_state->engineReady) return;
+    ma_engine_listener_set_position(&m_state->engine,
+                                    static_cast<ma_uint32>(listenerIndex), x,
+                                    y, z);
+}
+
+void MiniaudioSound::setListenerOrientation(int listenerIndex, float forwardX,
+                                            float forwardY, float forwardZ,
+                                            float upX, float upY, float upZ) {
+    if (!m_state->engineReady) return;
+    ma_engine_listener_set_direction(&m_state->engine,
+                                     static_cast<ma_uint32>(listenerIndex),
+                                     forwardX, forwardY, forwardZ);
+    ma_engine_listener_set_world_up(&m_state->engine,
+                                    static_cast<ma_uint32>(listenerIndex),
+                                    upX, upY, upZ);
+}
+
+}  // namespace platform::sound::miniaudio
+
+namespace platform_internal {
+::platform::sound::IPlatformSound& PlatformSound_get() {
+    static ::platform::sound::miniaudio::MiniaudioSound instance;
+    return instance;
+}
+}  // namespace platform_internal
diff --git a/targets/platform/sound/miniaudio/MiniaudioSound.h b/targets/platform/sound/miniaudio/MiniaudioSound.h
new file mode 100644
index 000000000..44a7845e5
--- /dev/null
+++ b/targets/platform/sound/miniaudio/MiniaudioSound.h
@@ -0,0 +1,61 @@
+#pragma once
+
+#include <memory>
+
+#include "platform/sound/IPlatformSound.h"
+
+// Forward-declare the miniaudio state struct so this header doesn't
+// need to include miniaudio.h - keeps the include footprint small for
+// any consumer of the backend header.
+namespace platform::sound::miniaudio {
+
+struct State;
+
+class MiniaudioSound : public IPlatformSound {
+public:
+    MiniaudioSound();
+    ~MiniaudioSound() override;
+
+    // Move-only - the engine owns hardware state.
+    MiniaudioSound(MiniaudioSound&&) noexcept;
+    MiniaudioSound& operator=(MiniaudioSound&&) noexcept;
+    MiniaudioSound(const MiniaudioSound&) = delete;
+    MiniaudioSound& operator=(const MiniaudioSound&) = delete;
+
+    // -- IPlatformSound --
+
+    void init(int listenerCount) override;
+    void shutdown() override;
+    void tick() override;
+
+    void setMasterVolume(float volume) override;
+
+    [[nodiscard]] SoundHandle playSoundFromFile(
+        const std::string& path, const PlaySoundParams& params) override;
+    void stopSound(SoundHandle handle) override;
+    [[nodiscard]] bool isSoundPlaying(SoundHandle handle) const override;
+    void setSoundVolume(SoundHandle handle, float volume) override;
+    void setSoundPosition(SoundHandle handle, float x, float y,
+                          float z) override;
+    void setSoundPitch(SoundHandle handle, float pitch) override;
+    void releaseSound(SoundHandle handle) override;
+
+    [[nodiscard]] MusicHandle playMusicFromFile(
+        const std::string& path, const PlayMusicParams& params) override;
+    void stopMusic(MusicHandle handle) override;
+    [[nodiscard]] bool isMusicPlaying(MusicHandle handle) const override;
+    void setMusicVolume(MusicHandle handle, float volume) override;
+    void setMusicPitch(MusicHandle handle, float pitch) override;
+    void releaseMusic(MusicHandle handle) override;
+
+    void setListenerPosition(int listenerIndex, float x, float y,
+                             float z) override;
+    void setListenerOrientation(int listenerIndex, float forwardX,
+                                float forwardY, float forwardZ, float upX,
+                                float upY, float upZ) override;
+
+private:
+    std::unique_ptr<State> m_state;
+};
+
+}  // namespace platform::sound::miniaudio
diff --git a/targets/platform/sound/sound.h b/targets/platform/sound/sound.h
new file mode 100644
index 000000000..41dba077f
--- /dev/null
+++ b/targets/platform/sound/sound.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include "platform/sound/IPlatformSound.h"
+
+// Function accessor backed by a function-local static (Meyers singleton).
+// Same pattern as input/renderer/profile/storage/fs - SIOF-safe.
+//
+// The macro lets call sites keep using `PlatformSound.foo()` syntax;
+// the expansion is just a function call returning a reference, which
+// LTO inlines.
+
+namespace platform_internal {
+::platform::sound::IPlatformSound& PlatformSound_get();
+}
+
+#define PlatformSound (::platform_internal::PlatformSound_get())