diff --git a/docs/TESTED_MODELS.md b/docs/TESTED_MODELS.md
index 16463fa..6791c3c 100644
--- a/docs/TESTED_MODELS.md
+++ b/docs/TESTED_MODELS.md
@@ -74,7 +74,8 @@ Titelgenerierung und Kontextkompression in Hermes.
 
 | Datum | Modell | Test | Ergebnis | Status / Entscheidung | Beleg |
 |---|---|---|---|---|---|
-| 08.09.2026 | `ACE-Step/acestep-v15-xl-sft` mit `acestep-5Hz-lm-1.7B`, offizielles ACE-Step-1.5-Image `sha256:95652cd780c78a1b1a7f6f0335530430f0ae53d96c7c12d59f9f39fa23d38567` | 30 s Instrumental, Thinking/LM aktiv, Batch 1, RTX 5080 16 GiB, automatischer CPU-Offload und INT8 Weight-only DiT | erfolgreich in 15,39 s: LM 8,00 s, DiT 7,39 s, MP3 0,82 s; PyTorch meldete maximal 9,38 GiB CUDA-Allokation; kein OOM/CUDA-Fehler | **Beta-Test bestanden**; Klangabnahme und Hermes-/Router-Integration noch offen | Athena: `/data/music/acestep/batch_1788873234/`; [SPECIALIZED_MODEL_ROADMAP.md](SPECIALIZED_MODEL_ROADMAP.md) |
+| 08.–10.09.2026 | `ACE-Step/acestep-v15-xl-sft` mit `acestep-5Hz-lm-1.7B`, offizielles ACE-Step-1.5-Image `sha256:95652cd780c78a1b1a7f6f0335530430f0ae53d96c7c12d59f9f39fa23d38567` | Mehrere Instrumentaltests bis 244 s; abschließender Kontrolllauf mit geladenem 1.7B-Planer, `thinking=True`, XL-SFT 4B, 80 Schritten, Guidance 8 und Shift 3 | technisch vollständig und schnell, aber wiederholt nur Geräusche/Krach oder musikalisch chaotische Ergebnisse; der letzte Lauf schließt einen bloß fehlenden Planer als Ursache aus | **qualitativ verworfen**; Container und Daten zunächst nur für den direkten HeartMuLa-A/B-Rückweg erhalten | Athena: `/data/music/acestep/`; [SPECIALIZED_MODEL_ROADMAP.md](SPECIALIZED_MODEL_ROADMAP.md) |
+| 10.09.2026 | `HeartMuLa/HeartMuLa-oss-3B-happy-new-year` mit `HeartMuLa/HeartCodec-oss-20260123`, heartlib `3783bdb8441f2c298b1e64c8651173aac200361c` | Isolierter 20-s-Instrumentaltest mit offiziellen Standardwerten; HeartMuLa BF16 auf RTX 5080, HeartCodec FP32 auf RTX 3060 | Modell und Codec laden stabil; 20,08-s-Stereoausgabe erfolgreich in rund 27 s erzeugt, 48 kHz/24-Bit-PCM. Referenzaudio wird upstream noch nicht unterstützt, Instrumentalsteuerung ist experimentell | **technischer Test bestanden, Hörabnahme offen** | [heartmula-3b](../experiments/heartmula-3b/README.md); Athena: `/data/music/heartmula/heartmula-1789064239-b3f2ca75.wav` |
 
 ## Audio-Trennung
 
diff --git a/experiments/heartmula-3b/Dockerfile b/experiments/heartmula-3b/Dockerfile
new file mode 100644
index 0000000..38be00a
--- /dev/null
+++ b/experiments/heartmula-3b/Dockerfile
@@ -0,0 +1,22 @@
+FROM pytorch/pytorch:2.9.1-cuda12.8-cudnn9-runtime
+
+ARG HEARTLIB_COMMIT=3783bdb8441f2c298b1e64c8651173aac200361c
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends git ffmpeg curl \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN git clone https://github.com/HeartMuLa/heartlib.git /opt/heartlib \
+    && git -C /opt/heartlib checkout "${HEARTLIB_COMMIT}" \
+    && pip install --no-cache-dir -e /opt/heartlib \
+    && pip install --no-cache-dir gradio==5.49.1 uvicorn==0.35.0
+
+COPY app.py /opt/app/app.py
+
+WORKDIR /opt/app
+ENV PYTHONUNBUFFERED=1 \
+    HEARTMULA_MODEL_PATH=/models/ckpt \
+    HEARTMULA_OUTPUT_DIR=/output
+
+EXPOSE 7860
+CMD ["python", "/opt/app/app.py"]
diff --git a/experiments/heartmula-3b/README.md b/experiments/heartmula-3b/README.md
new file mode 100644
index 0000000..133ad1b
--- /dev/null
+++ b/experiments/heartmula-3b/README.md
@@ -0,0 +1,49 @@
+# HeartMuLa 3B quality test
+
+Reversible A/B test of the public
+`HeartMuLa/HeartMuLa-oss-3B-happy-new-year` model with
+`HeartMuLa/HeartCodec-oss-20260123`.
+
+The model and codec are deliberately split across Athena's GPUs:
+
+- HeartMuLa BF16: RTX 5080 (`cuda:0` inside the container)
+- HeartCodec FP32: RTX 3060 (`cuda:1` inside the container)
+
+The public model does not yet support reference-audio conditioning. Pure
+instrumental generation is exposed as an explicitly experimental option.
+Generated files are lossless 48-kHz WAV files under `/data/music/heartmula`.
+
+The container intentionally has no `com.mike-ai.music-worker` label while it
+is being evaluated. This prevents it from conflicting with the production
+profile controller's single ACE-Step worker.
+
+## Checkpoints
+
+The expected persistent layout on Athena is:
+
+```text
+/data/models/heartmula/ckpt/
+├── HeartMuLa-oss-3B/
+├── HeartCodec-oss/
+├── gen_config.json
+└── tokenizer.json
+```
+
+## Test operation
+
+Only after the current music worker has been stopped:
+
+```sh
+cd /opt/mike-ai/heartmula-3b
+docker compose up -d heartmula-test
+docker compose logs -f heartmula-test
+```
+
+The temporary test UI is then available on port `7863`. Stop it with:
+
+```sh
+docker compose down
+```
+
+Do not remove ACE-Step or change the dashboard/profile controller until the
+A/B test has been accepted.
diff --git a/experiments/heartmula-3b/app.py b/experiments/heartmula-3b/app.py
new file mode 100644
index 0000000..a34f800
--- /dev/null
+++ b/experiments/heartmula-3b/app.py
@@ -0,0 +1,148 @@
+from __future__ import annotations
+
+import os
+import threading
+import time
+import uuid
+from pathlib import Path
+
+import gradio as gr
+import soundfile as sf
+import torch
+import uvicorn
+from fastapi import FastAPI
+from heartlib import HeartMuLaGenPipeline
+
+
+MODEL_PATH = os.environ.get("HEARTMULA_MODEL_PATH", "/models/ckpt")
+OUTPUT_DIR = Path(os.environ.get("HEARTMULA_OUTPUT_DIR", "/output"))
+MULA_DEVICE = os.environ.get("HEARTMULA_MULA_DEVICE", "cuda:0")
+CODEC_DEVICE = os.environ.get("HEARTMULA_CODEC_DEVICE", "cuda:1")
+
+OUTPUT_DIR.mkdir(parents=True, exist_ok=True)
+
+pipeline: HeartMuLaGenPipeline | None = None
+load_error = ""
+generation_lock = threading.Lock()
+
+
+class AthenaHeartMuLaPipeline(HeartMuLaGenPipeline):
+    """Write 24-bit WAV directly; torch 2.9 otherwise requires TorchCodec."""
+
+    def postprocess(self, model_outputs, save_path: str):
+        frames = model_outputs["frames"].to(self.codec_device)
+        wav = self.codec.detokenize(frames)
+        self._unload()
+        audio = wav.to(torch.float32).cpu().numpy().T
+        sf.write(save_path, audio, 48_000, format="WAV", subtype="PCM_24")
+
+
+def load_pipeline() -> None:
+    global pipeline, load_error
+    try:
+        pipeline = AthenaHeartMuLaPipeline.from_pretrained(
+            MODEL_PATH,
+            device={
+                "mula": torch.device(MULA_DEVICE),
+                "codec": torch.device(CODEC_DEVICE),
+            },
+            dtype={"mula": torch.bfloat16, "codec": torch.float32},
+            version="3B",
+            lazy_load=False,
+        )
+    except Exception as exc:
+        load_error = f"{type(exc).__name__}: {exc}"
+        raise
+
+
+def generate(
+    tags: str,
+    lyrics: str,
+    instrumental: bool,
+    duration_seconds: int,
+    topk: int,
+    temperature: float,
+    cfg_scale: float,
+):
+    if pipeline is None:
+        raise gr.Error(f"Modell ist nicht bereit. {load_error}".strip())
+    tags = ",".join(part.strip() for part in tags.split(",") if part.strip())
+    if not tags:
+        raise gr.Error("Bitte mindestens ein Musik-Tag angeben.")
+    if instrumental:
+        effective_lyrics = "[Instrumental]"
+    else:
+        effective_lyrics = lyrics.strip()
+        if not effective_lyrics:
+            raise gr.Error("Für ein Lied mit Gesang fehlt der Liedtext.")
+
+    target = OUTPUT_DIR / f"heartmula-{int(time.time())}-{uuid.uuid4().hex[:8]}.wav"
+    with generation_lock, torch.inference_mode():
+        pipeline(
+            {"lyrics": effective_lyrics, "tags": tags},
+            max_audio_length_ms=int(duration_seconds) * 1000,
+            save_path=str(target),
+            topk=int(topk),
+            temperature=float(temperature),
+            cfg_scale=float(cfg_scale),
+        )
+    return str(target), (
+        f"Fertig: {target.name} · WAV 48 kHz. "
+        "Instrumental ist bei der öffentlichen 3B-Version experimentell."
+    )
+
+
+with gr.Blocks(title="HeartMuLa 3B – Athena Test") as demo:
+    gr.Markdown(
+        "# HeartMuLa 3B – Athena Test\n"
+        "Offizielles öffentliches 3B-Modell. HeartMuLa läuft auf der RTX 5080, "
+        "HeartCodec verlustarm in FP32 auf der RTX 3060. "
+        "Referenzaudio wird von dieser Version noch nicht unterstützt."
+    )
+    tags = gr.Textbox(
+        label="Stil und Instrumente (Komma-getrennte Tags)",
+        value="synthwave,retrowave,1980s,melodic,nostalgic,arpeggiated synthesizer,drum machine,atmospheric,cinematic",
+        lines=3,
+    )
+    lyrics = gr.Textbox(
+        label="Liedtext mit Abschnitten wie [Verse], [Chorus], [Bridge]",
+        lines=14,
+        placeholder="[Verse]\n...\n\n[Chorus]\n...",
+    )
+    instrumental = gr.Checkbox(label="Instrumental (experimentell)", value=True)
+    duration = gr.Slider(20, 240, value=60, step=5, label="Maximale Dauer in Sekunden")
+    with gr.Accordion("Sampling – offizielle Standardwerte", open=False):
+        topk = gr.Slider(1, 200, value=50, step=1, label="Top-k")
+        temperature = gr.Slider(0.1, 2.0, value=1.0, step=0.05, label="Temperatur")
+        cfg_scale = gr.Slider(1.0, 4.0, value=1.5, step=0.1, label="CFG")
+    run = gr.Button("Musik erzeugen", variant="primary")
+    audio = gr.Audio(label="Ergebnis", type="filepath")
+    status = gr.Textbox(label="Status", interactive=False)
+    run.click(
+        generate,
+        inputs=[tags, lyrics, instrumental, duration, topk, temperature, cfg_scale],
+        outputs=[audio, status],
+    )
+
+demo.queue(default_concurrency_limit=1, max_size=4)
+
+api = FastAPI()
+
+
+@api.get("/healthz")
+def healthz():
+    return {
+        "ready": pipeline is not None,
+        "error": load_error or None,
+        "model": "HeartMuLa-oss-3B-happy-new-year",
+        "codec": "HeartCodec-oss-20260123",
+        "mula_device": MULA_DEVICE,
+        "codec_device": CODEC_DEVICE,
+    }
+
+
+api = gr.mount_gradio_app(api, demo, path="/")
+
+if __name__ == "__main__":
+    load_pipeline()
+    uvicorn.run(api, host="0.0.0.0", port=7860)
diff --git a/experiments/heartmula-3b/compose.yaml b/experiments/heartmula-3b/compose.yaml
new file mode 100644
index 0000000..de72ee9
--- /dev/null
+++ b/experiments/heartmula-3b/compose.yaml
@@ -0,0 +1,32 @@
+services:
+  heartmula-test:
+    build:
+      context: .
+      args:
+        HEARTLIB_COMMIT: 3783bdb8441f2c298b1e64c8651173aac200361c
+    image: mike-ai/heartmula:3b-3783bdb
+    container_name: mike-ai-heartmula-test
+    restart: "no"
+    environment:
+      NVIDIA_VISIBLE_DEVICES: "GPU-8ad38c6c-5a01-9d8e-1dfa-ed662ad78fbe,GPU-4834d9d7-5b61-3004-1fb3-4ae49d482d4b"
+      NVIDIA_DRIVER_CAPABILITIES: compute,utility
+      HEARTMULA_MULA_DEVICE: cuda:0
+      HEARTMULA_CODEC_DEVICE: cuda:1
+    volumes:
+      - /data/models/heartmula:/models:ro
+      - /data/music/heartmula:/output
+    ports:
+      - "7863:7860"
+    deploy:
+      resources:
+        reservations:
+          devices:
+            - driver: nvidia
+              count: all
+              capabilities: [gpu]
+    healthcheck:
+      test: ["CMD", "curl", "-fsS", "http://127.0.0.1:7860/healthz"]
+      interval: 15s
+      timeout: 5s
+      retries: 20
+      start_period: 180s