diff --git a/.gitignore b/.gitignore
index da29124..f084241 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,7 @@ saves/
 node_modules/
 .env
 pipeline/.genprops/
+pipeline/.genaudio/
 web/assets/models/
 pipeline/.peds_orig/
 pipeline/.props_orig/
diff --git a/E-progress.md b/E-progress.md
index 517d546..e484533 100644
--- a/E-progress.md
+++ b/E-progress.md
@@ -1,8 +1,32 @@
 # LANE E — ASSETS · progress (PROCITY-E)
 
-*2026-07-14. Owner: PROCITY-E. Scope: `pipeline/*`, `web/assets/*`, `web/assets/manifest.json`.
-Reviewed against `docs/LANES/LANE_E_ASSETS.md` + `docs/LANES/ROUND3_INSTRUCTIONS.md`. Nothing in
-other lanes' files was touched.*
+*Owner: PROCITY-E. Scope: `pipeline/*`, `web/assets/*`. Nothing in other lanes' files was touched.*
+
+## Round 11 (AUDIO round — E leads) · 2026-07-15
+
+Stood up the audio pack, free + on-device. **Tool: 100% procedural synthesis** (numpy → ffmpeg) —
+picked over neural gen because it's $0, deterministic/seeded, perfectly loopable, and parody-safe by
+construction (documented in README § audio, per Fable's ask).
+
+- **`pipeline/gen_audio.py`** — a small numpy DSP engine (oscillators, ADSR, filters, reverb,
+  seamless-loop crossfade, a note sequencer + drum synth). 23 assets, seeded, `--dry-run`/`--only`.
+- **`web/assets/audio/`** — 6 ambience beds (street day/night, rain, 3 interior roomtones), 13 sfx
+  (doorbell, door, till, record-riffle, toast, tram bell + rumble, 6 footsteps), 4 instrumental 90s
+  music loops (record-shop, milkbar, video-synth, arcade). OGG/Opus + M4A/AAC. **8.1 MB** of 25 MB.
+- **Manifest** `audio:{ambience,sfx,music}` — files + m4a fallback + loop + gain; interior roomtone/
+  music carry `types[]` for seed-pick per shop (like facades); footstep is `{surface:[variants]}`.
+  `build_manifest.py` builds it, `validate_manifest.py` checks it. **qa green, audio 23, 0 errors.**
+- **Verified** technically (I synthesise, I can't subjectively *listen*): spectrogram sheet
+  `docs/shots/laneE/audio_spectrograms.png` + numeric — peaks ≤ -0.4 dBFS (no clip), **all loops
+  seamless**, durations correct. **Subjective ear-check is John's/F's** (flagged honestly).
+- Provenance in `AUDIT.md` (§ Round 11). House audio law respected on the E side: silent-happy
+  (manifest lists only shipped files), lazy-load metadata, seeded flavour. B wires WebAudio, C gives
+  the `room.audio` contract, F integrates + owns the **v2.1 tag/push** — I did **not** push.
+
+---
+
+*Round 3 and earlier below.*
+*Reviewed against `docs/LANES/LANE_E_ASSETS.md` + `docs/LANES/ROUND3_INSTRUCTIONS.md`.*
 
 ## Round 9 (Fable) — VRAM audit + depot hygiene (ship-round DD)
 
diff --git a/docs/shots/laneE/audio_spectrograms.png b/docs/shots/laneE/audio_spectrograms.png
new file mode 100644
index 0000000..5a17f05
Binary files /dev/null and b/docs/shots/laneE/audio_spectrograms.png differ
diff --git a/pipeline/AUDIT.md b/pipeline/AUDIT.md
index e2b908c..5b651fb 100644
--- a/pipeline/AUDIT.md
+++ b/pipeline/AUDIT.md
@@ -391,3 +391,29 @@ required for the tag.** Two follow-ups flagged for **v3, not now** (bigger than
 
 **Depot/manifest hygiene (E2):** `validate --depot` 0 err · pack-QA 3/3 valid · provenance-drift clean
 (`_published.json` == 27 live procity GLBs) · 15 stock atlases live, **0 orphans**. All green post-R8.
+
+## Round 11 — audio pack provenance
+
+**Every audio file is 100% original procedural synthesis** (`pipeline/gen_audio.py`, numpy on the
+MODELBEAST box → ffmpeg). No neural model, no sample library, no third-party recording touched — so
+the whole pack is **CC0-equivalent original work** and **parody-safe by construction**: there is
+nothing to imitate, every waveform is an oscillator/noise render. Music beds are original chord
+progressions/melodies — no imitation of any specific real recording. Tool choice is documented in
+`pipeline/README.md` (§ audio): synthesis over local MusicGen/stable-audio because it's $0,
+deterministic/seeded, perfectly loopable, and licence-clean.
+
+| group | files | origin |
+|---|---|---|
+| ambience (6) | street-day/night, rain, roomtone-retail/milkbar/video | filtered-noise beds + synthesised events (birds/crickets/drops/hum) 🟢 |
+| sfx (13) | doorbell, door-open, till, riffle, toast, tram-bell, tram-rumble, footsteps ×6 | additive-bell + filtered-noise transients 🟢 |
+| music (4) | record-shop, milkbar, video-synth, arcade | original synth loops (bass+chords+drums+lead) 🟢 |
+
+- **Format**: OGG/Opus primary (48 kHz) + M4A/AAC fallback (44.1 kHz). **Loudness**: long beds/music
+  ffmpeg `loudnorm` I=-16 LUFS / TP=-1.5 (single-pass EBU R128); short SFX peak-normalised (-3…-6 dBFS).
+- **Verified** (I synthesise, I can't subjectively listen): spectrogram sheet
+  `docs/shots/laneE/audio_spectrograms.png` (content/character) + numeric pass — peaks ≤ -0.4 dBFS
+  (no clip), **all loops seamless** (wrap-jump ≤ internal step), durations correct. **Final subjective
+  ear-check is John's/F's** — flagged honestly.
+- **Budget**: 8.1 MB shipped (2.8 MB ogg + 5.3 MB m4a) vs the 25 MB cap; lazy-loaded per manifest.
+- Files ship in `web/assets/audio/` (committed, like `gen/` skins); WAV scratch `pipeline/.genaudio/`
+  is git-ignored. Contract in `manifest.json` → `audio:{ambience,sfx,music}`.
diff --git a/pipeline/README.md b/pipeline/README.md
index 7e2a596..8b421be 100644
--- a/pipeline/README.md
+++ b/pipeline/README.md
@@ -95,13 +95,34 @@ python3 pipeline/stage_local_depot.py     # mirror _normalized/*.glb → web/ass
 # then load the game with ?localdepot=1 — depot:<file> resolves to assets/models/<file> instead of the CDN
 ```
 
+### 8. Audio pack — `gen_audio.py`  *(round-11: DONE, free, on-device)*
+**Tool choice (Fable asked E to pick + document): pure procedural synthesis in numpy**, not a neural
+model. MODELBEAST has no audio operator, and for this pack synthesis wins outright — $0, no model
+download, deterministic/seeded (house law), **perfectly seamless loops** (neural gens don't loop),
+**parody-safe by construction** (every sample is an original oscillator/noise render — nothing to
+imitate), and precise ≤25 MB budget control. Pipeline: numpy synth → WAV → ffmpeg OGG/Opus (+ M4A/AAC).
+```bash
+PY=~/Documents/MODELBEAST/venvs/mflux/bin/python     # numpy lives in the mflux venv
+$PY pipeline/gen_audio.py --dry-run                  # list the 23-asset pack + budget
+$PY pipeline/gen_audio.py                            # render all → web/assets/audio/*.ogg + *.m4a
+$PY pipeline/gen_audio.py --only music               # just the music beds
+python3 pipeline/build_manifest.py                   # catalogue → manifest.json audio:{ambience,sfx,music}
+```
+23 assets, **8.1 MB** shipped (opus+aac): 6 ambience beds (street day/night, rain, 3 roomtones), 13
+sfx (doorbell, door, till, riffle, toast, tram bell/rumble, 6 footsteps), 4 instrumental 90s music
+loops. Loudness: beds/music `loudnorm` -16 LUFS, sfx peak-normalised. **Ear-ball** = spectrogram sheet
+`docs/shots/laneE/audio_spectrograms.png` + numeric loop-seam/peak check (I can't subjectively listen —
+final ear-check is John's/F's). Add assets by editing `PACK` in `gen_audio.py` + the `AUDIO_*` maps in
+`build_manifest.py`. WAV scratch `pipeline/.genaudio/` is git-ignored; OGG/M4A ship committed.
+
 ## Cost summary
 
 | step | cost |
 |---|---|
 | audit, normalize, manifest, validate, publish | **free** (compute + bandwidth) |
 | facade skin gap-fill (23 imgs) | **free** — done on-device (MODELBEAST flux_local); cloud fallback ~9¢ |
-| MeshGod hero props (9 solids) | **~$2.70** — gated on John (local `sf3d`/`trellis_mac` is free but HF-gated) |
+| hero props (round-3) | **free** — 5 via MODELBEAST trellis_mac; glass-case/bus-shelter on fal.ai list (≤$2.70, John's go) |
+| audio pack (round-11, 23 assets) | **free** — 100% procedural synthesis (numpy → ffmpeg), $0, no model |
 
 ## Artifacts (not committed — regenerated from the steps)
 
diff --git a/pipeline/build_manifest.py b/pipeline/build_manifest.py
index e31b64f..c67004f 100644
--- a/pipeline/build_manifest.py
+++ b/pipeline/build_manifest.py
@@ -16,8 +16,28 @@ GEN = os.path.join(ROOT, "web", "assets", "gen")
 RESULTS = os.path.join(ROOT, "pipeline", "_normalize_results.json")       # library GLBs
 PROPS_RESULTS = os.path.join(ROOT, "pipeline", "_props_results.json")     # round-3 hero props
 OUT = os.path.join(ROOT, "web", "assets", "manifest.json")
+AUDIO = os.path.join(ROOT, "web", "assets", "audio")                       # round-11 audio pack
 DEPOT = "https://digalot.fyi/3god"
 
+# ── curated audio contract (files from pipeline/gen_audio.py). Interior beds/music carry types[]
+# — shop types that use them — so Lane C/F seed-pick from the matching pool, exactly like facades. ──
+AUDIO_STREET = {"street-day": 0.5, "street-night": 0.5, "rain": 0.45}      # Lane B street beds
+AUDIO_ROOMTONE = {   # interior room-tone key -> shop types it suits
+    "retail":  ["record", "opshop", "book", "toy", "pawn", "stall", "general"],
+    "milkbar": ["milkbar"],
+    "video":   ["video", "dept", "arcade"],
+}
+AUDIO_MUSIC = {      # interior music key -> (gain, shop types, note)
+    "record-shop": (0.55, ["record"], "record shop plays music"),
+    "milkbar":     (0.50, ["milkbar", "general"], "milk bar radio"),
+    "video-synth": (0.50, ["video"], "video store synth hum"),
+    "arcade":      (0.50, ["arcade", "dept"], "arcade cabinet"),
+}
+AUDIO_SFX = {"doorbell": 0.7, "door-open": 0.6, "till": 0.7, "riffle": 0.6,  # one-shots
+             "toast": 0.5, "tram-bell": 0.7}
+AUDIO_SFX_LOOP = {"tram-rumble": 0.5}
+AUDIO_FOOTSTEPS = {"pavement": 3, "timber": 3}                             # surface -> variants
+
 # ── depot-reuse: already-published GLBs we point at without a local normalize. The round-3 reuse
 # check found vintage-cash-register.glb live on 3GOD (from thriftgod_hero) — reuse it for the
 # universal till instead of re-generating. Manual footprint/height (no local file to measure);
@@ -83,6 +103,46 @@ def rel(p):
     return "gen/" + os.path.basename(p)
 
 
+def build_audio():
+    """The audio section: ambience (street beds + interior roomtone), sfx (one-shots + footstep
+    variant arrays), music. Only assets present on disk are listed — silent-happy by construction."""
+    def ref(n):
+        return ({"file": f"audio/{n}.ogg", "fallback": f"audio/{n}.m4a"}
+                if os.path.isfile(os.path.join(AUDIO, n + ".ogg")) else None)
+    ambience = {}
+    for k, g in AUDIO_STREET.items():
+        r = ref("ambience-" + k)
+        if r:
+            ambience[k] = {**r, "loop": True, "gain": g, "scope": "street"}
+    for k, types in AUDIO_ROOMTONE.items():
+        r = ref("roomtone-" + k)
+        if r:
+            ambience["roomtone-" + k] = {**r, "loop": True, "gain": 0.35, "scope": "interior", "types": types}
+    music = {}
+    for k, (g, types, note) in AUDIO_MUSIC.items():
+        r = ref("music-" + k)
+        if r:
+            music[k] = {**r, "loop": True, "gain": g, "types": types, "note": note}
+    sfx = {}
+    for k, g in AUDIO_SFX.items():
+        r = ref("sfx-" + k)
+        if r:
+            sfx[k] = {**r, "gain": g}
+    for k, g in AUDIO_SFX_LOOP.items():
+        r = ref("sfx-" + k)
+        if r:
+            sfx[k] = {**r, "gain": g, "loop": True}
+    footsteps = {}
+    for surf, n in AUDIO_FOOTSTEPS.items():
+        vs = [ref(f"step-{surf}-{i}") for i in range(1, n + 1)]
+        vs = [v for v in vs if v]
+        if vs:
+            footsteps[surf] = vs
+    if footsteps:
+        sfx["footstep"] = footsteps
+    return {"ambience": ambience, "sfx": sfx, "music": music}
+
+
 def build():
     have = {os.path.splitext(os.path.basename(f))[0] for f in glob.glob(GEN + "/*.jpg")}
 
@@ -198,11 +258,16 @@ def build():
                            "these to the exposed side face; other types reuse the front skin",
             "fallbacks": "every asset is optional — missing file => primitive/flat-colour, never a crash",
             "load": "fittings/furniture load from depot as depot:<file>; skins are local gen/<file>",
+            "audio": "OGG/Opus primary + M4A/AAC fallback; loop:true beds are seamless; gain is a "
+                     "suggested 0-1 playback level; interior roomtone/music carry types[] (seed-pick "
+                     "per shop, like facades); footstep is {surface:[variants]}. Silent-happy: any "
+                     "missing file => silence, never an error; ?mute=1 / ?noassets=1 => no audio fetch.",
         },
         "skins": skins,
         "fittings": fittings,
         "furniture": furniture,
         "fittingAliases": fitting_aliases,
+        "audio": build_audio(),
     }
     with open(OUT, "w") as fh:
         json.dump(manifest, fh, indent=2)
@@ -210,6 +275,8 @@ def build():
     print(f"  facades {len(facade)}  skies {len(sky)}  grounds {len(ground)}  "
           f"wallpapers {len(wall)}  floors {len(floor)}  surfaces {len(surface)}  awnings {len(awning)}")
     print(f"  fittings {len(fittings)}  furniture {len(furniture)}")
+    au = manifest["audio"]
+    print(f"  audio: ambience {len(au['ambience'])}  sfx {len(au['sfx'])}  music {len(au['music'])}")
 
 
 if __name__ == "__main__":
diff --git a/pipeline/gen_audio.py b/pipeline/gen_audio.py
new file mode 100644
index 0000000..ba539e3
--- /dev/null
+++ b/pipeline/gen_audio.py
@@ -0,0 +1,649 @@
+#!/usr/bin/env python3
+"""PROCITY audio pack — 100% procedural synthesis, on-device, $0 (round-11 audio round).
+
+TOOL CHOICE (Fable asked E to pick + document): **pure procedural synthesis in numpy**, not a
+neural model. MODELBEAST has no audio operator, and for THIS pack synthesis wins on every axis:
+  * $0, no 2–15 GB model download, runs in the mflux venv (numpy only).
+  * Deterministic + seeded (citySeed/shopId flavour is house law) — same seed, same sound.
+  * Perfect **seamless loops** (we crossfade the tail into the head) — neural gens don't loop.
+  * **Parody-safe by construction**: every sample is an original oscillator/noise render, so there
+    is no way to imitate a specific real recording. Instrumental originals only.
+  * Precise budget control (≤25 MB): we choose length + Opus bitrate per asset.
+
+Pipeline:  synth (numpy float32) -> WAV (stdlib wave, int16) -> ffmpeg -> OGG/Opus (+ M4A/AAC).
+Loudness:  long beds/music -> ffmpeg loudnorm (EBU R128, target -16 LUFS integrated); short SFX ->
+           peak-normalized in-synth (loudnorm is unreliable under ~3 s).
+
+    <mflux-venv-python> pipeline/gen_audio.py --dry-run     # list the pack + budget, no render
+    <mflux-venv-python> pipeline/gen_audio.py               # render everything -> web/assets/audio/
+    <mflux-venv-python> pipeline/gen_audio.py --only music  # just the music beds
+    <mflux-venv-python> pipeline/gen_audio.py --wav-only    # keep .genaudio/*.wav, skip ffmpeg (debug)
+
+Run with the numpy-having interpreter:  ~/Documents/MODELBEAST/venvs/mflux/bin/python
+House audio law: the game runs silent-and-happy with zero assets — none of this blocks anyone.
+"""
+import os, sys, math, wave, struct, subprocess, hashlib, json, zlib
+import numpy as np
+
+SR = 44100
+ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+RAW = os.path.join(ROOT, "pipeline", ".genaudio")          # WAV scratch (git-ignored)
+OUT = os.path.join(ROOT, "web", "assets", "audio")         # shipped OGG/M4A
+os.makedirs(RAW, exist_ok=True)
+os.makedirs(OUT, exist_ok=True)
+FF = "ffmpeg"
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# DSP toolkit (pure numpy)
+# ─────────────────────────────────────────────────────────────────────────────
+def seed_of(name):
+    return zlib.crc32(name.encode()) & 0xFFFFFFFF
+
+
+def rng(name):
+    return np.random.default_rng(seed_of(name))
+
+
+def tarr(dur):
+    return np.arange(int(dur * SR)) / SR
+
+
+def sine(f, dur, phase=0.0):
+    return np.sin(2 * np.pi * f * tarr(dur) + phase)
+
+
+def _phase(f, dur):
+    # allow f to be scalar or array (for vibrato/glide)
+    n = int(dur * SR)
+    if np.isscalar(f):
+        f = np.full(n, f, dtype=np.float64)
+    else:
+        f = np.resize(f, n)
+    return np.cumsum(2 * np.pi * f / SR)
+
+
+def osc(f, dur, kind="sine"):
+    ph = _phase(f, dur)
+    if kind == "sine":
+        return np.sin(ph)
+    if kind == "tri":
+        return 2 / np.pi * np.arcsin(np.sin(ph))
+    if kind == "saw":
+        return 2 * ((ph / (2 * np.pi)) % 1.0) - 1
+    if kind == "square":
+        return np.sign(np.sin(ph))
+    if kind == "pulse25":
+        return np.where((ph / (2 * np.pi)) % 1.0 < 0.25, 1.0, -1.0)
+    raise ValueError(kind)
+
+
+def noise(dur, r=None, kind="white"):
+    n = int(dur * SR)
+    r = r or np.random.default_rng(0)
+    x = r.standard_normal(n)
+    if kind == "pink":  # ~ -3 dB/oct via cheap one-pole cascade
+        b = [0.0, 0.0, 0.0]
+        out = np.empty(n)
+        for i in range(n):
+            b[0] = 0.99765 * b[0] + x[i] * 0.0990460
+            b[1] = 0.96300 * b[1] + x[i] * 0.2965164
+            b[2] = 0.57000 * b[2] + x[i] * 1.0526913
+            out[i] = b[0] + b[1] + b[2] + x[i] * 0.1848
+        return out / 4
+    return x
+
+
+def adsr(dur, a=0.01, d=0.1, s=0.7, r=0.1, sl=None):
+    n = int(dur * SR)
+    sl = (dur - a - d - r) if sl is None else sl
+    sl = max(sl, 0.0)
+    segs = [(a, 0, 1), (d, 1, s), (sl, s, s), (r, s, 0)]
+    env = np.concatenate([np.linspace(x0, x1, max(int(t * SR), 1)) for t, x0, x1 in segs])
+    return np.resize(env, n)
+
+
+def lp1(x, cutoff):
+    # one-pole low-pass
+    a = math.exp(-2 * math.pi * cutoff / SR)
+    y = np.empty_like(x)
+    acc = 0.0
+    for i in range(len(x)):
+        acc = (1 - a) * x[i] + a * acc
+        y[i] = acc
+    return y
+
+
+def hp1(x, cutoff):
+    return x - lp1(x, cutoff)
+
+
+def biquad_lp(x, cutoff, q=0.707):
+    # RBJ low-pass biquad
+    w0 = 2 * math.pi * cutoff / SR
+    alpha = math.sin(w0) / (2 * q)
+    cw = math.cos(w0)
+    b0 = (1 - cw) / 2; b1 = 1 - cw; b2 = (1 - cw) / 2
+    a0 = 1 + alpha; a1 = -2 * cw; a2 = 1 - alpha
+    b0, b1, b2, a1, a2 = (b0/a0, b1/a0, b2/a0, a1/a0, a2/a0)
+    y = np.empty_like(x); x1 = x2 = y1 = y2 = 0.0
+    for i in range(len(x)):
+        y0 = b0*x[i] + b1*x1 + b2*x2 - a1*y1 - a2*y2
+        x2, x1 = x1, x[i]; y2, y1 = y1, y0
+        y[i] = y0
+    return y
+
+
+def bandpass(x, lo, hi):
+    return lp1(hp1(x, lo), hi)
+
+
+def softclip(x, drive=1.0):
+    return np.tanh(x * drive)
+
+
+def fade(x, fin=0.01, fout=0.01):
+    n = len(x); ai = int(fin * SR); ao = int(fout * SR)
+    if ai: x[:ai] *= np.linspace(0, 1, ai)
+    if ao: x[-ao:] *= np.linspace(1, 0, ao)
+    return x
+
+
+def peaknorm(x, target_db=-3.0):
+    p = np.max(np.abs(x)) or 1.0
+    return x * (10 ** (target_db / 20) / p)
+
+
+def seamless(x, xf=0.75):
+    """Return a loop of length len(x)-xf*SR that plays end->start seamlessly, by crossfading
+    the tail (xf s) over the head. Input should be rendered xf longer than the wanted loop."""
+    k = int(xf * SR)
+    if k <= 0 or len(x) <= k:
+        return x
+    body = x[:-k].copy()
+    tail = x[-k:]
+    w = np.linspace(0, 1, k)
+    if body.ndim == 2:                          # stereo: broadcast window across channels
+        w = w[:, None]
+    body[:k] = body[:k] * w + tail * (1 - w)   # head = head*rise + tail*fall
+    return body
+
+
+def stereo(l, r=None):
+    if r is None:
+        r = l
+    n = max(len(l), len(r))
+    out = np.zeros((n, 2), dtype=np.float64)
+    out[:len(l), 0] = l; out[:len(r), 1] = r
+    return out
+
+
+def pan(x, p):  # p in [-1,1]
+    p = (p + 1) / 2
+    return stereo(x * math.cos(p * math.pi / 2), x * math.sin(p * math.pi / 2))
+
+
+def mix(*layers):
+    n = max(len(a) for a in layers)
+    ch = max((a.ndim == 2 and a.shape[1] or 1) for a in layers)
+    out = np.zeros((n, ch) if ch == 2 else n, dtype=np.float64)
+    for a in layers:
+        if ch == 2 and a.ndim == 1:
+            a = stereo(a)
+        if ch == 2:
+            out[:len(a)] += a
+        else:
+            out[:len(a)] += a
+    return out
+
+
+def schroeder_reverb(x, mix_amt=0.2, decay=0.5):
+    if x.ndim == 2:
+        return np.stack([schroeder_reverb(x[:, c], mix_amt, decay) for c in range(2)], axis=1)
+    out = np.zeros(len(x) + SR)
+    out[:len(x)] = x
+    for dl, g in [(1116, 0.805), (1188, 0.827), (1277, 0.783), (1356, 0.764)]:
+        buf = np.zeros(len(out))
+        gg = g * decay
+        for i in range(dl, len(out)):
+            buf[i] = out[i] + gg * buf[i - dl]
+        out = out + buf * 0.25
+    wet = out[:len(x)]
+    wet = wet / (np.max(np.abs(wet)) or 1.0)
+    return (1 - mix_amt) * x + mix_amt * wet
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# instruments + drums (for music beds)
+# ─────────────────────────────────────────────────────────────────────────────
+def midi_hz(m):
+    return 440.0 * 2 ** ((m - 69) / 12)
+
+
+def synth_note(midi, dur, kind="saw", a=0.005, d=0.08, s=0.6, rel=0.1,
+               cutoff=2500, detune=0.0, vib=0.0):
+    f = midi_hz(midi)
+    if vib:
+        f = f * (1 + vib * 0.006 * np.sin(2 * np.pi * 5 * tarr(dur)))
+    x = osc(f, dur, kind)
+    if detune:
+        x = 0.5 * x + 0.5 * osc(midi_hz(midi) * (1 + detune), dur, kind)
+    x = x * adsr(dur, a, d, s, rel)
+    if cutoff < SR / 2:
+        x = biquad_lp(x, cutoff, 0.8)
+    return x
+
+
+def epiano(midi, dur):
+    f = midi_hz(midi)
+    x = (np.sin(2*np.pi*f*tarr(dur)) + 0.5*np.sin(2*np.pi*2*f*tarr(dur)*1.001)
+         + 0.25*np.sin(2*np.pi*3*f*tarr(dur)))
+    return x * adsr(dur, 0.005, 0.5, 0.25, 0.3)
+
+
+def pad(midi, dur, detune=0.008):
+    x = (osc(midi_hz(midi), dur, "saw") + osc(midi_hz(midi)*(1+detune), dur, "saw")
+         + osc(midi_hz(midi)*(1-detune), dur, "saw")) / 3
+    x = biquad_lp(x, 1800, 0.7)
+    return x * adsr(dur, 0.4, 0.2, 0.8, 0.5)
+
+
+def kick(dur=0.28):
+    n = int(dur * SR)
+    f = np.linspace(120, 45, n)
+    x = np.sin(2 * np.pi * np.cumsum(f) / SR) * np.exp(-np.linspace(0, 9, n))
+    click = noise(0.005) * np.exp(-np.linspace(0, 40, int(0.005*SR)))
+    return mix(x, np.concatenate([click, np.zeros(n - len(click))]))
+
+
+def snare(dur=0.2, r=None):
+    n = int(dur * SR)
+    body = np.sin(2*np.pi*190*tarr(dur)) * np.exp(-np.linspace(0, 14, n))
+    nz = noise(dur, r) * np.exp(-np.linspace(0, 16, n))
+    return 0.5*body + 0.8*bandpass(nz, 1200, 6000)
+
+
+def hat(dur=0.05, r=None, open_=False):
+    n = int(dur * SR)
+    nz = bandpass(noise(dur, r), 7000, 16000)
+    env = np.exp(-np.linspace(0, 3 if open_ else 30, n))
+    return nz * env
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# sequencer for music beds
+# ─────────────────────────────────────────────────────────────────────────────
+def render_line(notes, bpm, instr, gap=0.0):
+    """notes: list of (midi_or_None, beats). instr: fn(midi,dur)->array. Returns concatenated."""
+    spb = 60.0 / bpm
+    parts = []
+    for midi, beats in notes:
+        dur = beats * spb
+        if midi is None:
+            parts.append(np.zeros(int(dur * SR)))
+        else:
+            x = instr(midi, max(dur - gap, 0.05))
+            x = np.concatenate([x, np.zeros(int(dur * SR) - len(x))]) if len(x) < int(dur*SR) else x[:int(dur*SR)]
+            parts.append(x)
+    return np.concatenate(parts)
+
+
+def render_drums(pattern, bpm, bars, r):
+    """pattern: dict 'k'/'s'/'h' -> list of 16th-step indices (0..15) for one bar."""
+    spb = 60.0 / bpm
+    step = spb / 4
+    barlen = int(16 * step * SR)
+    out = np.zeros(barlen * bars)
+    voices = {"k": lambda: kick(), "s": lambda: snare(r=r), "h": lambda: hat(r=r),
+              "o": lambda: hat(r=r, open_=True)}
+    for b in range(bars):
+        for v, steps in pattern.items():
+            for s in steps:
+                pos = int((b * 16 + s) * step * SR)
+                smp = voices[v]()
+                end = min(pos + len(smp), len(out))
+                out[pos:end] += smp[:end - pos]
+    return out
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# AMBIENCE generators (loopable ~40s)
+# ─────────────────────────────────────────────────────────────────────────────
+AMB_LEN = 40.0
+XF = 1.0
+
+
+def amb_street_day(name):
+    r = rng(name)
+    dur = AMB_LEN + XF
+    wind = lp1(noise(dur, r, "pink"), 600) * 0.6
+    # distant traffic: slow-swelling band-passed noise
+    traf = bandpass(noise(dur, r), 120, 900)
+    swell = 0.5 + 0.5 * np.sin(2 * np.pi * 0.05 * tarr(dur) + r.random() * 6)
+    traf = traf * swell * 0.35
+    # sparse bird chirps
+    birds = np.zeros(int(dur * SR))
+    for _ in range(int(dur * 0.7)):
+        at = r.uniform(0, dur - 0.4)
+        f0 = r.uniform(2200, 4200)
+        cd = r.uniform(0.06, 0.16)
+        chirp = np.sin(2*np.pi*np.cumsum(np.linspace(f0, f0*r.uniform(0.8,1.4), int(cd*SR)))/SR)
+        chirp *= np.hanning(len(chirp)) * r.uniform(0.05, 0.12)
+        p = int(at * SR); birds[p:p+len(chirp)] += chirp
+    body = mix(pan(wind, -0.2), pan(traf, 0.1), pan(birds, r.uniform(-0.5, 0.5)))
+    return seamless(body, XF)
+
+
+def amb_street_night(name):
+    r = rng(name)
+    dur = AMB_LEN + XF
+    hum = lp1(noise(dur, r, "pink"), 200) * 0.4 + osc(60, dur, "sine") * 0.02
+    # crickets: rhythmic AM high tone
+    base = osc(4500, dur, "sine")
+    trill = (np.sin(2*np.pi*22*tarr(dur)) > 0.3).astype(float)
+    gate = (0.5 + 0.5*np.sin(2*np.pi*0.7*tarr(dur))) > 0.55
+    crickets = base * trill * gate * 0.04
+    crickets = bandpass(crickets, 3500, 6000)
+    body = mix(pan(hum, 0), pan(crickets, 0.3), pan(bandpass(noise(dur, r), 200, 500)*0.1, -0.3))
+    return seamless(body, XF)
+
+
+def amb_rain(name):
+    r = rng(name)
+    dur = AMB_LEN + XF
+    base = bandpass(noise(dur, r), 800, 9000) * 0.5      # hiss
+    low = lp1(noise(dur, r), 400) * 0.25                  # rumble
+    drops = np.zeros(int(dur * SR))
+    for _ in range(int(dur * 12)):
+        at = r.uniform(0, dur - 0.05); f = r.uniform(1500, 5000)
+        d = np.sin(2*np.pi*f*tarr(0.02)) * np.exp(-np.linspace(0, 30, int(0.02*SR))) * r.uniform(0.05, 0.15)
+        p = int(at*SR); drops[p:p+len(d)] += d
+    body = mix(pan(base, 0), pan(low, 0), pan(drops, r.uniform(-0.4, 0.4)))
+    return seamless(body, XF)
+
+
+def _roomtone(name, hum_f, hiss_lo, hiss_hi, hiss_g, extra=None):
+    r = rng(name)
+    dur = AMB_LEN + XF
+    hum = (osc(hum_f, dur, "sine")*0.5 + osc(hum_f*2, dur, "sine")*0.2) * 0.06
+    hiss = bandpass(noise(dur, r), hiss_lo, hiss_hi) * hiss_g
+    layers = [pan(hum, 0), pan(hiss, 0)]
+    if extra is not None:
+        layers.append(pan(extra(r, dur), 0.2))
+    return seamless(mix(*layers), XF)
+
+
+def amb_roomtone_retail(name):
+    return _roomtone(name, 100, 200, 2000, 0.05)
+
+
+def amb_roomtone_milkbar(name):
+    # fridge compressor buzz
+    return _roomtone(name, 120, 300, 1500, 0.05,
+                     extra=lambda r, d: softclip(osc(120, d, "tri")*0.4, 2)*0.05)
+
+
+def amb_roomtone_video(name):
+    # faint CRT flyback whine (~15.7 kHz) + hum
+    return _roomtone(name, 60, 400, 3000, 0.03,
+                     extra=lambda r, d: osc(15734, d, "sine")*0.012)
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# SFX generators (short, dry, peak-normalized)
+# ─────────────────────────────────────────────────────────────────────────────
+def _bell(midi, dur, partials, decay):
+    f = midi_hz(midi)
+    x = np.zeros(int(dur * SR))
+    for mult, g in partials:
+        x[:] += g * np.sin(2*np.pi*f*mult*tarr(dur))
+    return x * np.exp(-np.linspace(0, decay, len(x)))
+
+
+def sfx_doorbell(name):
+    ding = _bell(76, 0.9, [(1, 1), (2.76, 0.4), (5.4, 0.15)], 5)   # E5
+    dong = _bell(72, 1.1, [(1, 1), (2.76, 0.4), (5.4, 0.15)], 5)   # C5
+    x = np.concatenate([ding[:int(0.45*SR)], dong])
+    return peaknorm(fade(x, 0.002, 0.05), -3)
+
+
+def sfx_door_open(name):
+    r = rng(name)
+    latch = noise(0.03, r) * np.exp(-np.linspace(0, 30, int(0.03*SR)))
+    latch = bandpass(latch, 800, 5000)
+    creak = bandpass(noise(0.4, r), 300, 1200)
+    creak *= (0.3 + 0.7*np.abs(np.sin(2*np.pi*7*tarr(0.4)))) * np.linspace(1, 0, int(0.4*SR)) * 0.4
+    x = np.concatenate([latch, np.zeros(int(0.05*SR)), creak])
+    return peaknorm(fade(x, 0.002, 0.03), -4)
+
+
+def sfx_till(name):
+    # pleasant buy-confirm: two-note bell arpeggio + tiny mechanical "cha"
+    r = rng(name)
+    n1 = _bell(72, 0.5, [(1, 1), (2.0, 0.3), (3.01, 0.2)], 6)
+    n2 = _bell(79, 0.7, [(1, 1), (2.0, 0.3), (3.01, 0.2)], 6)
+    cha = bandpass(noise(0.04, r), 2000, 8000) * np.exp(-np.linspace(0, 25, int(0.04*SR))) * 0.5
+    x = mix(np.concatenate([cha, np.zeros(int(0.6*SR))]),
+            np.concatenate([n1[:int(0.12*SR)], n2]))
+    return peaknorm(fade(x, 0.002, 0.05), -3)
+
+
+def sfx_riffle(name):
+    # record-bin dig: a run of soft filtered noise "flips"
+    r = rng(name)
+    out = np.zeros(int(0.9 * SR))
+    tpos = 0.02
+    while tpos < 0.85:
+        flip = bandpass(noise(0.05, r), 500, 4000) * np.exp(-np.linspace(0, 22, int(0.05*SR)))
+        flip *= r.uniform(0.4, 1.0)
+        p = int(tpos * SR); out[p:p+len(flip)] += flip
+        tpos += r.uniform(0.05, 0.11)
+    return peaknorm(fade(out, 0.002, 0.03), -5)
+
+
+def sfx_toast(name):
+    x = np.concatenate([synth_note(84, 0.06, "sine", 0.002, 0.02, 0.3, 0.03, cutoff=SR//2),
+                        synth_note(88, 0.12, "sine", 0.002, 0.03, 0.3, 0.06, cutoff=SR//2)])
+    return peaknorm(fade(x, 0.002, 0.03), -6)
+
+
+def sfx_tram_bell(name):
+    x = _bell(84, 1.2, [(1, 1), (2.4, 0.5), (3.9, 0.25), (5.2, 0.12)], 4)
+    d2 = np.concatenate([np.zeros(int(0.18*SR)),
+                         _bell(84, 1.0, [(1, 1), (2.4, 0.5), (3.9, 0.25)], 4)])
+    d2 = np.concatenate([d2, np.zeros(len(x))])[:len(x)]   # zero-pad/trim to x
+    return peaknorm(fade(x + 0.5*d2, 0.002, 0.08), -3)
+
+
+def sfx_tram_rumble(name):
+    # loopable continuous low rumble (~3 s) — smooth (no discrete clacks that would collide at
+    # the loop fold); the wheel-clatter texture is a modulated mid-band noise instead.
+    r = rng(name); dur = 3.0 + XF
+    low = lp1(noise(dur, r), 120) * 0.6 + osc(45, dur, "sine") * 0.2
+    clatter = bandpass(noise(dur, r), 200, 1400)
+    lfo = 0.4 + 0.6 * (0.5 + 0.5 * np.sin(2 * np.pi * 6 * tarr(dur)))   # 6 Hz wheel wobble
+    body = mix(low, clatter * lfo * 0.18)
+    return seamless(peaknorm(body, -6), XF)
+
+
+def _footstep(name, bright, res_f):
+    r = rng(name)
+    thump = osc(np.linspace(res_f*1.6, res_f, int(0.05*SR)), 0.05, "sine")
+    thump *= np.exp(-np.linspace(0, 18, int(0.05*SR)))
+    click = bandpass(noise(0.04, r), 1500 if bright else 700, 9000 if bright else 4000)
+    click *= np.exp(-np.linspace(0, 30, int(0.04*SR))) * (0.7 if bright else 0.4)
+    x = mix(thump, click) * r.uniform(0.8, 1.0)
+    return peaknorm(fade(x, 0.001, 0.02), -6)
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# MUSIC beds (instrumental, loopable, seeded, parody-safe originals)
+# ─────────────────────────────────────────────────────────────────────────────
+def loop_music(body, revmix=0.12, tail=1.2):
+    """Seamless music loop: render the reverb ring-out PAST the loop end into `tail` seconds of
+    silence, then crossfade that genuine ring-out over the head. Result: when the loop restarts,
+    the decay from the 'previous' pass bleeds into the start — no click. (The broken way is to
+    append a head-copy, which makes tail==head and the crossfade a no-op.)"""
+    if body.ndim == 1:
+        body = stereo(body)
+    T = int(tail * SR)
+    wet = schroeder_reverb(np.concatenate([body, np.zeros((T, 2))]), revmix)
+    return seamless(wet, tail)
+
+
+def music_record_shop(name):
+    r = rng(name); bpm = 96; bars = 8
+    spb = 60/bpm; barlen = int(4*spb*SR)
+    # Am7 - D7 - Gmaj7 - Cmaj7 kind of groove (original voicing), root midis:
+    prog = [45, 50, 43, 48] * 2            # A, D, G, C (one per bar)
+    third = [+3, +4, +4, +4]; seventh = [+10, +10, +11, +11]
+    bass = render_line(sum([[(root, 0.75), (None, 0.25), (root+7, 0.5), (root+12, 0.5),
+                             (root, 1.0), (root+7, 1.0)] for root in prog], []),
+                       bpm, lambda m, d: synth_note(m-12, d, "saw", 0.005, 0.1, 0.5, 0.05, cutoff=700))
+    chords = []
+    for i, root in enumerate(prog):
+        for _ in range(4):  # comp on each beat
+            ch = mix(epiano(root+12, spb*0.9), epiano(root+12+third[i % 4], spb*0.9),
+                     epiano(root+12+seventh[i % 4], spb*0.9))
+            chords.append(ch * 0.5)
+    chords = np.concatenate([np.concatenate([c, np.zeros(max(int(spb*SR)-len(c),0))])[:int(spb*SR)] for c in chords])
+    drums = render_drums({"k": [0, 6, 8], "s": [4, 12], "h": [0, 2, 4, 6, 8, 10, 12, 14]}, bpm, bars, r)
+    body = mix(pan(bass, 0)*0.9, pan(chords, -0.15)*0.7, pan(drums, 0.1)*0.6)
+    return loop_music(body, 0.12)
+
+
+def music_milkbar(name):
+    r = rng(name); bpm = 108; bars = 8
+    spb = 60/bpm
+    prog = [48, 55, 53, 50]  # C G F D-ish bright pop (original)
+    bass = render_line(sum([[(root-12, 1.0), (root-12, 1.0), (root-5, 1.0), (root-12, 1.0)] for root in prog]*2, []),
+                       bpm, lambda m, d: synth_note(m, d, "tri", 0.005, 0.1, 0.6, 0.05, cutoff=900))
+    lead = render_line([(r.choice([root, root+4, root+7, root+12]), 0.5) for root in prog for _ in range(8)],
+                       bpm, lambda m, d: synth_note(m+12, d, "square", 0.005, 0.05, 0.4, 0.05, cutoff=3000))
+    drums = render_drums({"k": [0, 8], "s": [4, 12], "h": [0, 2, 4, 6, 8, 10, 12, 14], "o": [14]}, bpm, bars, r)
+    body = mix(pan(bass, 0)*0.9, pan(lead, 0.2)*0.35, pan(drums, 0)*0.55)
+    return loop_music(body, 0.1)
+
+
+def music_video_synth(name):
+    r = rng(name); bpm = 84; bars = 8
+    spb = 60/bpm
+    prog = [45, 45, 50, 43]  # moody synthwave (original)
+    pads = np.concatenate([mix(pad(root, 4*spb), pad(root+7, 4*spb), pad(root+10, 4*spb))[:int(4*spb*SR)]
+                           for root in prog]*2)
+    arp_notes = []
+    for root in prog*2:
+        for s in [0, 7, 12, 7]:
+            arp_notes.append((root+12+s, 0.5))
+    arp = render_line(arp_notes, bpm, lambda m, d: synth_note(m, d, "pulse25", 0.002, 0.05, 0.3, 0.05, cutoff=2600))
+    bass = render_line(sum([[(root-12, 2.0), (root-12, 2.0)] for root in prog]*2, []),
+                       bpm, lambda m, d: synth_note(m, d, "saw", 0.01, 0.1, 0.7, 0.1, cutoff=500))
+    drums = render_drums({"k": [0, 8], "s": [8], "h": [2, 6, 10, 14]}, bpm, bars, r)
+    body = mix(pan(pads, 0)*0.5, pan(arp, 0.3)*0.3, pan(bass, 0)*0.8, pan(drums, 0)*0.4)
+    return loop_music(body, 0.2)
+
+
+def music_arcade(name):
+    r = rng(name); bpm = 132; bars = 8
+    spb = 60/bpm
+    prog = [48, 48, 53, 55]  # upbeat chiptune (original)
+    lead_scale = [0, 2, 4, 7, 9, 12]
+    lead = render_line([(root+12+r.choice(lead_scale), 0.25) for root in prog for _ in range(16)],
+                       bpm, lambda m, d: synth_note(m, d, "square", 0.001, 0.02, 0.5, 0.02, cutoff=SR//2))
+    bass = render_line(sum([[(root-12, 0.5), (root, 0.5)]*4 for root in prog]*2, []),
+                       bpm, lambda m, d: synth_note(m, d, "pulse25", 0.002, 0.03, 0.5, 0.02, cutoff=SR//2))
+    hats = render_drums({"h": list(range(0, 16, 2)), "k": [0, 4, 8, 12], "s": [4, 12]}, bpm, bars, r)
+    body = mix(pan(lead, 0.1)*0.4, pan(bass, -0.1)*0.5, pan(hats, 0)*0.4)
+    return loop_music(body, 0.03)
+
+
+# ─────────────────────────────────────────────────────────────────────────────
+# the pack:  name -> (category, generator, {loop, gain, note})
+# ─────────────────────────────────────────────────────────────────────────────
+PACK = {
+    # ambience (loop, quiet beds)
+    "ambience-street-day":   ("ambience", amb_street_day,   dict(loop=True,  gain=0.5)),
+    "ambience-street-night": ("ambience", amb_street_night, dict(loop=True,  gain=0.5)),
+    "ambience-rain":         ("ambience", amb_rain,         dict(loop=True,  gain=0.45, note="layer over street beds")),
+    "roomtone-retail":       ("ambience", amb_roomtone_retail,  dict(loop=True, gain=0.35)),
+    "roomtone-milkbar":      ("ambience", amb_roomtone_milkbar, dict(loop=True, gain=0.35)),
+    "roomtone-video":        ("ambience", amb_roomtone_video,   dict(loop=True, gain=0.3)),
+    # sfx
+    "sfx-doorbell":   ("sfx", sfx_doorbell,   dict(loop=False, gain=0.7)),
+    "sfx-door-open":  ("sfx", sfx_door_open,  dict(loop=False, gain=0.6)),
+    "sfx-till":       ("sfx", sfx_till,       dict(loop=False, gain=0.7)),
+    "sfx-riffle":     ("sfx", sfx_riffle,     dict(loop=False, gain=0.6)),
+    "sfx-toast":      ("sfx", sfx_toast,      dict(loop=False, gain=0.5)),
+    "sfx-tram-bell":  ("sfx", sfx_tram_bell,  dict(loop=False, gain=0.7)),
+    "sfx-tram-rumble":("sfx", sfx_tram_rumble,dict(loop=True,  gain=0.5)),
+    # footsteps (2 surfaces x 3 variants)
+    "step-pavement-1": ("sfx", lambda n: _footstep(n, True, 90),  dict(loop=False, gain=0.4)),
+    "step-pavement-2": ("sfx", lambda n: _footstep(n, True, 95),  dict(loop=False, gain=0.4)),
+    "step-pavement-3": ("sfx", lambda n: _footstep(n, True, 85),  dict(loop=False, gain=0.4)),
+    "step-timber-1":   ("sfx", lambda n: _footstep(n, False, 70), dict(loop=False, gain=0.4)),
+    "step-timber-2":   ("sfx", lambda n: _footstep(n, False, 75), dict(loop=False, gain=0.4)),
+    "step-timber-3":   ("sfx", lambda n: _footstep(n, False, 65), dict(loop=False, gain=0.4)),
+    # music beds (loop, instrumental originals)
+    "music-record-shop": ("music", music_record_shop, dict(loop=True, gain=0.55, note="record shop")),
+    "music-milkbar":     ("music", music_milkbar,     dict(loop=True, gain=0.5,  note="milk bar radio")),
+    "music-video-synth": ("music", music_video_synth, dict(loop=True, gain=0.5,  note="video store")),
+    "music-arcade":      ("music", music_arcade,      dict(loop=True, gain=0.5,  note="arcade")),
+}
+
+
+def write_wav(path, x):
+    if x.ndim == 1:
+        x = stereo(x)
+    peak = np.max(np.abs(x))
+    if peak > 0.95:                       # limiter: never clip (loudnorm sets final loudness)
+        x = x * (0.95 / peak)
+    x = np.clip(x, -1.0, 1.0)
+    pcm = (x * 32767).astype("<i2")
+    with wave.open(path, "wb") as w:
+        w.setnchannels(2); w.setsampwidth(2); w.setframerate(SR)
+        w.writeframes(pcm.tobytes())
+
+
+def encode(wav, base, category):
+    """WAV -> OGG/Opus (+ M4A/AAC). Long beds/music get loudnorm; SFX are pre-peak-normalized."""
+    ogg = os.path.join(OUT, base + ".ogg")
+    m4a = os.path.join(OUT, base + ".m4a")
+    af = ["-af", "loudnorm=I=-16:TP=-1.5:LRA=11"] if category in ("ambience", "music") else []
+    br = "96k" if category == "music" else ("80k" if category == "ambience" else "64k")
+    subprocess.run([FF, "-y", "-i", wav, *af, "-c:a", "libopus", "-b:a", br, "-ar", "48000", ogg],
+                   check=True, capture_output=True)
+    subprocess.run([FF, "-y", "-i", wav, *af, "-c:a", "aac", "-b:a", "128k", "-ar", "44100", m4a],
+                   check=True, capture_output=True)
+    return os.path.getsize(ogg), os.path.getsize(m4a)
+
+
+if __name__ == "__main__":
+    only = sys.argv[sys.argv.index("--only") + 1] if "--only" in sys.argv else ""
+    wav_only = "--wav-only" in sys.argv
+    todo = {k: v for k, v in PACK.items() if not only or only in k or only == v[0]}
+
+    if "--dry-run" in sys.argv:
+        print(f"{len(todo)} audio assets (procedural synth, $0):")
+        by = {}
+        for k, (cat, _, meta) in sorted(todo.items()):
+            by.setdefault(cat, []).append(k)
+        for cat, ks in by.items():
+            print(f"  [{cat}] {len(ks)}: {', '.join(ks)}")
+        sys.exit(0)
+
+    print(f"rendering {len(todo)} assets @ {SR}Hz  (numpy synth -> ffmpeg opus+aac)")
+    total_ogg = total_m4a = 0
+    for k, (cat, gen, meta) in todo.items():
+        wav = os.path.join(RAW, k + ".wav")
+        x = gen(k)
+        write_wav(wav, x)
+        dur = (len(x) / SR)
+        if wav_only:
+            print(f"  [{cat}] {k}  {dur:.1f}s  (wav only)")
+            continue
+        og, m4 = encode(wav, k, cat)
+        total_ogg += og; total_m4a += m4
+        print(f"  [{cat}] {k:22s} {dur:5.1f}s  ogg={og//1024:>4}KB  m4a={m4//1024:>4}KB")
+    if not wav_only:
+        print(f"\ntotal shipped: ogg {total_ogg/1e6:.2f}MB + m4a {total_m4a/1e6:.2f}MB "
+              f"= {(total_ogg+total_m4a)/1e6:.2f}MB  (budget 25MB)")
diff --git a/pipeline/validate_manifest.py b/pipeline/validate_manifest.py
index dc948e0..d67f486 100644
--- a/pipeline/validate_manifest.py
+++ b/pipeline/validate_manifest.py
@@ -116,6 +116,22 @@ def main():
             manifest_files.add(entry["file"])
             n_glb += 1
 
+    # audio pack (round-11): if the manifest names an audio file it must ship locally (both the
+    # ogg primary and the m4a fallback). Silent-happy is a runtime rule, not a licence to dangle refs.
+    n_audio = 0
+    def _chk_audio(e):
+        for key in ("file", "fallback"):
+            if key in e:
+                check_skin(e[key])
+    for grp in m.get("audio", {}).values():
+        for v in grp.values():
+            if isinstance(v, dict) and "file" in v:
+                _chk_audio(v); n_audio += 1
+            elif isinstance(v, dict):              # footstep {surface:[variants]}
+                for arr in v.values():
+                    for e in arr:
+                        _chk_audio(e); n_audio += 1
+
     # provenance-drift gate: every manifest depot GLB must be recorded in _published.json, so a
     # clobbered/stale provenance record (the R5 bug) fails QA loudly instead of hiding.
     recpath = os.path.join(ROOT, "pipeline", "_published.json")
@@ -138,7 +154,7 @@ def main():
 
     print(f"manifest v{m.get('version')} — facades {len(facade)}, "
           f"skins {sum(len(v) if isinstance(v, list) else (len(v) if isinstance(v, dict) else 0) for v in sk.values())} groups, "
-          f"GLBs {n_glb}")
+          f"GLBs {n_glb}, audio {n_audio}")
     for w in warnings:
         print(f"  WARN  {w}")
     if errors:
diff --git a/web/assets/audio/ambience-rain.m4a b/web/assets/audio/ambience-rain.m4a
new file mode 100644
index 0000000..652713b
Binary files /dev/null and b/web/assets/audio/ambience-rain.m4a differ
diff --git a/web/assets/audio/ambience-rain.ogg b/web/assets/audio/ambience-rain.ogg
new file mode 100644
index 0000000..cd41ae1
Binary files /dev/null and b/web/assets/audio/ambience-rain.ogg differ
diff --git a/web/assets/audio/ambience-street-day.m4a b/web/assets/audio/ambience-street-day.m4a
new file mode 100644
index 0000000..2735e22
Binary files /dev/null and b/web/assets/audio/ambience-street-day.m4a differ
diff --git a/web/assets/audio/ambience-street-day.ogg b/web/assets/audio/ambience-street-day.ogg
new file mode 100644
index 0000000..dffda7f
Binary files /dev/null and b/web/assets/audio/ambience-street-day.ogg differ
diff --git a/web/assets/audio/ambience-street-night.m4a b/web/assets/audio/ambience-street-night.m4a
new file mode 100644
index 0000000..2c495a6
Binary files /dev/null and b/web/assets/audio/ambience-street-night.m4a differ
diff --git a/web/assets/audio/ambience-street-night.ogg b/web/assets/audio/ambience-street-night.ogg
new file mode 100644
index 0000000..f0b3b88
Binary files /dev/null and b/web/assets/audio/ambience-street-night.ogg differ
diff --git a/web/assets/audio/music-arcade.m4a b/web/assets/audio/music-arcade.m4a
new file mode 100644
index 0000000..5001726
Binary files /dev/null and b/web/assets/audio/music-arcade.m4a differ
diff --git a/web/assets/audio/music-arcade.ogg b/web/assets/audio/music-arcade.ogg
new file mode 100644
index 0000000..e3c2377
Binary files /dev/null and b/web/assets/audio/music-arcade.ogg differ
diff --git a/web/assets/audio/music-milkbar.m4a b/web/assets/audio/music-milkbar.m4a
new file mode 100644
index 0000000..ea765ec
Binary files /dev/null and b/web/assets/audio/music-milkbar.m4a differ
diff --git a/web/assets/audio/music-milkbar.ogg b/web/assets/audio/music-milkbar.ogg
new file mode 100644
index 0000000..9a6c948
Binary files /dev/null and b/web/assets/audio/music-milkbar.ogg differ
diff --git a/web/assets/audio/music-record-shop.m4a b/web/assets/audio/music-record-shop.m4a
new file mode 100644
index 0000000..7061656
Binary files /dev/null and b/web/assets/audio/music-record-shop.m4a differ
diff --git a/web/assets/audio/music-record-shop.ogg b/web/assets/audio/music-record-shop.ogg
new file mode 100644
index 0000000..0032ce7
Binary files /dev/null and b/web/assets/audio/music-record-shop.ogg differ
diff --git a/web/assets/audio/music-video-synth.m4a b/web/assets/audio/music-video-synth.m4a
new file mode 100644
index 0000000..61bf6bf
Binary files /dev/null and b/web/assets/audio/music-video-synth.m4a differ
diff --git a/web/assets/audio/music-video-synth.ogg b/web/assets/audio/music-video-synth.ogg
new file mode 100644
index 0000000..ee6a3fe
Binary files /dev/null and b/web/assets/audio/music-video-synth.ogg differ
diff --git a/web/assets/audio/roomtone-milkbar.m4a b/web/assets/audio/roomtone-milkbar.m4a
new file mode 100644
index 0000000..60fda3a
Binary files /dev/null and b/web/assets/audio/roomtone-milkbar.m4a differ
diff --git a/web/assets/audio/roomtone-milkbar.ogg b/web/assets/audio/roomtone-milkbar.ogg
new file mode 100644
index 0000000..8e16e73
Binary files /dev/null and b/web/assets/audio/roomtone-milkbar.ogg differ
diff --git a/web/assets/audio/roomtone-retail.m4a b/web/assets/audio/roomtone-retail.m4a
new file mode 100644
index 0000000..88e67f6
Binary files /dev/null and b/web/assets/audio/roomtone-retail.m4a differ
diff --git a/web/assets/audio/roomtone-retail.ogg b/web/assets/audio/roomtone-retail.ogg
new file mode 100644
index 0000000..5f5ded5
Binary files /dev/null and b/web/assets/audio/roomtone-retail.ogg differ
diff --git a/web/assets/audio/roomtone-video.m4a b/web/assets/audio/roomtone-video.m4a
new file mode 100644
index 0000000..00f31ca
Binary files /dev/null and b/web/assets/audio/roomtone-video.m4a differ
diff --git a/web/assets/audio/roomtone-video.ogg b/web/assets/audio/roomtone-video.ogg
new file mode 100644
index 0000000..3779ed7
Binary files /dev/null and b/web/assets/audio/roomtone-video.ogg differ
diff --git a/web/assets/audio/sfx-door-open.m4a b/web/assets/audio/sfx-door-open.m4a
new file mode 100644
index 0000000..6b03bce
Binary files /dev/null and b/web/assets/audio/sfx-door-open.m4a differ
diff --git a/web/assets/audio/sfx-door-open.ogg b/web/assets/audio/sfx-door-open.ogg
new file mode 100644
index 0000000..91cf81e
Binary files /dev/null and b/web/assets/audio/sfx-door-open.ogg differ
diff --git a/web/assets/audio/sfx-doorbell.m4a b/web/assets/audio/sfx-doorbell.m4a
new file mode 100644
index 0000000..05b5666
Binary files /dev/null and b/web/assets/audio/sfx-doorbell.m4a differ
diff --git a/web/assets/audio/sfx-doorbell.ogg b/web/assets/audio/sfx-doorbell.ogg
new file mode 100644
index 0000000..585be96
Binary files /dev/null and b/web/assets/audio/sfx-doorbell.ogg differ
diff --git a/web/assets/audio/sfx-riffle.m4a b/web/assets/audio/sfx-riffle.m4a
new file mode 100644
index 0000000..a5417b1
Binary files /dev/null and b/web/assets/audio/sfx-riffle.m4a differ
diff --git a/web/assets/audio/sfx-riffle.ogg b/web/assets/audio/sfx-riffle.ogg
new file mode 100644
index 0000000..c70de7e
Binary files /dev/null and b/web/assets/audio/sfx-riffle.ogg differ
diff --git a/web/assets/audio/sfx-till.m4a b/web/assets/audio/sfx-till.m4a
new file mode 100644
index 0000000..52079a3
Binary files /dev/null and b/web/assets/audio/sfx-till.m4a differ
diff --git a/web/assets/audio/sfx-till.ogg b/web/assets/audio/sfx-till.ogg
new file mode 100644
index 0000000..0174559
Binary files /dev/null and b/web/assets/audio/sfx-till.ogg differ
diff --git a/web/assets/audio/sfx-toast.m4a b/web/assets/audio/sfx-toast.m4a
new file mode 100644
index 0000000..40217fc
Binary files /dev/null and b/web/assets/audio/sfx-toast.m4a differ
diff --git a/web/assets/audio/sfx-toast.ogg b/web/assets/audio/sfx-toast.ogg
new file mode 100644
index 0000000..3746a20
Binary files /dev/null and b/web/assets/audio/sfx-toast.ogg differ
diff --git a/web/assets/audio/sfx-tram-bell.m4a b/web/assets/audio/sfx-tram-bell.m4a
new file mode 100644
index 0000000..78c3ffd
Binary files /dev/null and b/web/assets/audio/sfx-tram-bell.m4a differ
diff --git a/web/assets/audio/sfx-tram-bell.ogg b/web/assets/audio/sfx-tram-bell.ogg
new file mode 100644
index 0000000..c4a2492
Binary files /dev/null and b/web/assets/audio/sfx-tram-bell.ogg differ
diff --git a/web/assets/audio/sfx-tram-rumble.m4a b/web/assets/audio/sfx-tram-rumble.m4a
new file mode 100644
index 0000000..5ef8897
Binary files /dev/null and b/web/assets/audio/sfx-tram-rumble.m4a differ
diff --git a/web/assets/audio/sfx-tram-rumble.ogg b/web/assets/audio/sfx-tram-rumble.ogg
new file mode 100644
index 0000000..0e70580
Binary files /dev/null and b/web/assets/audio/sfx-tram-rumble.ogg differ
diff --git a/web/assets/audio/step-pavement-1.m4a b/web/assets/audio/step-pavement-1.m4a
new file mode 100644
index 0000000..4df8ff2
Binary files /dev/null and b/web/assets/audio/step-pavement-1.m4a differ
diff --git a/web/assets/audio/step-pavement-1.ogg b/web/assets/audio/step-pavement-1.ogg
new file mode 100644
index 0000000..e647fc4
Binary files /dev/null and b/web/assets/audio/step-pavement-1.ogg differ
diff --git a/web/assets/audio/step-pavement-2.m4a b/web/assets/audio/step-pavement-2.m4a
new file mode 100644
index 0000000..5cdcf9f
Binary files /dev/null and b/web/assets/audio/step-pavement-2.m4a differ
diff --git a/web/assets/audio/step-pavement-2.ogg b/web/assets/audio/step-pavement-2.ogg
new file mode 100644
index 0000000..e772cdc
Binary files /dev/null and b/web/assets/audio/step-pavement-2.ogg differ
diff --git a/web/assets/audio/step-pavement-3.m4a b/web/assets/audio/step-pavement-3.m4a
new file mode 100644
index 0000000..9a4f33d
Binary files /dev/null and b/web/assets/audio/step-pavement-3.m4a differ
diff --git a/web/assets/audio/step-pavement-3.ogg b/web/assets/audio/step-pavement-3.ogg
new file mode 100644
index 0000000..6059af6
Binary files /dev/null and b/web/assets/audio/step-pavement-3.ogg differ
diff --git a/web/assets/audio/step-timber-1.m4a b/web/assets/audio/step-timber-1.m4a
new file mode 100644
index 0000000..75bb0c4
Binary files /dev/null and b/web/assets/audio/step-timber-1.m4a differ
diff --git a/web/assets/audio/step-timber-1.ogg b/web/assets/audio/step-timber-1.ogg
new file mode 100644
index 0000000..c6c58d6
Binary files /dev/null and b/web/assets/audio/step-timber-1.ogg differ
diff --git a/web/assets/audio/step-timber-2.m4a b/web/assets/audio/step-timber-2.m4a
new file mode 100644
index 0000000..402b0a3
Binary files /dev/null and b/web/assets/audio/step-timber-2.m4a differ
diff --git a/web/assets/audio/step-timber-2.ogg b/web/assets/audio/step-timber-2.ogg
new file mode 100644
index 0000000..d633c13
Binary files /dev/null and b/web/assets/audio/step-timber-2.ogg differ
diff --git a/web/assets/audio/step-timber-3.m4a b/web/assets/audio/step-timber-3.m4a
new file mode 100644
index 0000000..86e8ed6
Binary files /dev/null and b/web/assets/audio/step-timber-3.m4a differ
diff --git a/web/assets/audio/step-timber-3.ogg b/web/assets/audio/step-timber-3.ogg
new file mode 100644
index 0000000..9486981
Binary files /dev/null and b/web/assets/audio/step-timber-3.ogg differ
diff --git a/web/assets/manifest.json b/web/assets/manifest.json
index f31d90b..241a98a 100644
--- a/web/assets/manifest.json
+++ b/web/assets/manifest.json
@@ -8,7 +8,8 @@
     "facade_face": "facade entries without a 'face' key are front elevations (shop or house fronts); face:'side' entries are windowless corner-lot side walls with empty types \u2014 never select one as a shop front",
     "corner_lots": "corner lots expose a side wall: dedicated facade-<x>-side.jpg skins now exist for brick/render/weatherboard (face:'side') \u2014 Lane B maps these to the exposed side face; other types reuse the front skin",
     "fallbacks": "every asset is optional \u2014 missing file => primitive/flat-colour, never a crash",
-    "load": "fittings/furniture load from depot as depot:<file>; skins are local gen/<file>"
+    "load": "fittings/furniture load from depot as depot:<file>; skins are local gen/<file>",
+    "audio": "OGG/Opus primary + M4A/AAC fallback; loop:true beds are seamless; gain is a suggested 0-1 playback level; interior roomtone/music carry types[] (seed-pick per shop, like facades); footstep is {surface:[variants]}. Silent-happy: any missing file => silence, never an error; ?mute=1 / ?noassets=1 => no audio fetch."
   },
   "skins": {
     "facade": {
@@ -838,5 +839,180 @@
     "magazine_rack": "magazine_rack",
     "fridge": "drinks_fridge",
     "listening_corner": "listening_booth"
+  },
+  "audio": {
+    "ambience": {
+      "street-day": {
+        "file": "audio/ambience-street-day.ogg",
+        "fallback": "audio/ambience-street-day.m4a",
+        "loop": true,
+        "gain": 0.5,
+        "scope": "street"
+      },
+      "street-night": {
+        "file": "audio/ambience-street-night.ogg",
+        "fallback": "audio/ambience-street-night.m4a",
+        "loop": true,
+        "gain": 0.5,
+        "scope": "street"
+      },
+      "rain": {
+        "file": "audio/ambience-rain.ogg",
+        "fallback": "audio/ambience-rain.m4a",
+        "loop": true,
+        "gain": 0.45,
+        "scope": "street"
+      },
+      "roomtone-retail": {
+        "file": "audio/roomtone-retail.ogg",
+        "fallback": "audio/roomtone-retail.m4a",
+        "loop": true,
+        "gain": 0.35,
+        "scope": "interior",
+        "types": [
+          "record",
+          "opshop",
+          "book",
+          "toy",
+          "pawn",
+          "stall",
+          "general"
+        ]
+      },
+      "roomtone-milkbar": {
+        "file": "audio/roomtone-milkbar.ogg",
+        "fallback": "audio/roomtone-milkbar.m4a",
+        "loop": true,
+        "gain": 0.35,
+        "scope": "interior",
+        "types": [
+          "milkbar"
+        ]
+      },
+      "roomtone-video": {
+        "file": "audio/roomtone-video.ogg",
+        "fallback": "audio/roomtone-video.m4a",
+        "loop": true,
+        "gain": 0.35,
+        "scope": "interior",
+        "types": [
+          "video",
+          "dept",
+          "arcade"
+        ]
+      }
+    },
+    "sfx": {
+      "doorbell": {
+        "file": "audio/sfx-doorbell.ogg",
+        "fallback": "audio/sfx-doorbell.m4a",
+        "gain": 0.7
+      },
+      "door-open": {
+        "file": "audio/sfx-door-open.ogg",
+        "fallback": "audio/sfx-door-open.m4a",
+        "gain": 0.6
+      },
+      "till": {
+        "file": "audio/sfx-till.ogg",
+        "fallback": "audio/sfx-till.m4a",
+        "gain": 0.7
+      },
+      "riffle": {
+        "file": "audio/sfx-riffle.ogg",
+        "fallback": "audio/sfx-riffle.m4a",
+        "gain": 0.6
+      },
+      "toast": {
+        "file": "audio/sfx-toast.ogg",
+        "fallback": "audio/sfx-toast.m4a",
+        "gain": 0.5
+      },
+      "tram-bell": {
+        "file": "audio/sfx-tram-bell.ogg",
+        "fallback": "audio/sfx-tram-bell.m4a",
+        "gain": 0.7
+      },
+      "tram-rumble": {
+        "file": "audio/sfx-tram-rumble.ogg",
+        "fallback": "audio/sfx-tram-rumble.m4a",
+        "gain": 0.5,
+        "loop": true
+      },
+      "footstep": {
+        "pavement": [
+          {
+            "file": "audio/step-pavement-1.ogg",
+            "fallback": "audio/step-pavement-1.m4a"
+          },
+          {
+            "file": "audio/step-pavement-2.ogg",
+            "fallback": "audio/step-pavement-2.m4a"
+          },
+          {
+            "file": "audio/step-pavement-3.ogg",
+            "fallback": "audio/step-pavement-3.m4a"
+          }
+        ],
+        "timber": [
+          {
+            "file": "audio/step-timber-1.ogg",
+            "fallback": "audio/step-timber-1.m4a"
+          },
+          {
+            "file": "audio/step-timber-2.ogg",
+            "fallback": "audio/step-timber-2.m4a"
+          },
+          {
+            "file": "audio/step-timber-3.ogg",
+            "fallback": "audio/step-timber-3.m4a"
+          }
+        ]
+      }
+    },
+    "music": {
+      "record-shop": {
+        "file": "audio/music-record-shop.ogg",
+        "fallback": "audio/music-record-shop.m4a",
+        "loop": true,
+        "gain": 0.55,
+        "types": [
+          "record"
+        ],
+        "note": "record shop plays music"
+      },
+      "milkbar": {
+        "file": "audio/music-milkbar.ogg",
+        "fallback": "audio/music-milkbar.m4a",
+        "loop": true,
+        "gain": 0.5,
+        "types": [
+          "milkbar",
+          "general"
+        ],
+        "note": "milk bar radio"
+      },
+      "video-synth": {
+        "file": "audio/music-video-synth.ogg",
+        "fallback": "audio/music-video-synth.m4a",
+        "loop": true,
+        "gain": 0.5,
+        "types": [
+          "video"
+        ],
+        "note": "video store synth hum"
+      },
+      "arcade": {
+        "file": "audio/music-arcade.ogg",
+        "fallback": "audio/music-arcade.m4a",
+        "loop": true,
+        "gain": 0.5,
+        "types": [
+          "arcade",
+          "dept"
+        ],
+        "note": "arcade cabinet"
+      }
+    }
   }
 }
\ No newline at end of file