diff --git a/.gitattributes b/.gitattributes
index 9ddacc6..d92d407 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -3,3 +3,7 @@
 *.py text eol=lf
 *.md text eol=lf
 *.json text eol=lf
+
+# Preserve the approved binary stream and literal per-note audit bytes.
+examples/doebel/DOEBEL.VGM binary
+examples/doebel/NOTES.csv binary
diff --git a/README.md b/README.md
index 5892c11..75ea42d 100644
--- a/README.md
+++ b/README.md
@@ -139,3 +139,9 @@ non-owning speaker callback contract. `examples/dos_sfx_demo.c` builds as
 finite harpoon, silent gap, conch and all-channel stop sequence from
 foreground retrace polling only.
 
+[`examples/doebel/`](examples/doebel/README.md) adds an optional three-tone
+"Doebelinschmirtz Incorporated" jingle example using `lt_score`.
+`DOEBEL.EXE` plays it once in foreground DOS; the checked-in score header and
+PSG VGM need no Python preparation. The recognizable tune is a reduction of
+the referenced *Evil Jingle*, with separate musical attribution in the example.
+
diff --git a/examples/doebel/APPROVED.H b/examples/doebel/APPROVED.H
new file mode 100644
index 0000000..08128e8
--- /dev/null
+++ b/examples/doebel/APPROVED.H
@@ -0,0 +1,183 @@
+/* Frozen register fixture from the approved host audition.
+ * Musical attribution: README.md. Do not regenerate from candidate notes.
+ */
+#ifndef DOEBEL_APPROVED_H
+#define DOEBEL_APPROVED_H
+typedef struct { unsigned frame; lt_u8 byte; } doebel_approved_write;
+#define DOEBEL_APPROVED_WRITES 173U
+static const doebel_approved_write doebel_approved[] = {
+    { 0U, 0x9fU },
+    { 0U, 0xbfU },
+    { 0U, 0xdfU },
+    { 0U, 0xffU },
+    { 0U, 0x9fU },
+    { 0U, 0xbfU },
+    { 0U, 0xdfU },
+    { 0U, 0xffU },
+    { 0U, 0xe4U },
+    { 0U, 0x80U },
+    { 0U, 0x14U },
+    { 0U, 0x94U },
+    { 0U, 0xacU },
+    { 0U, 0x1aU },
+    { 0U, 0xbbU },
+    { 0U, 0xcaU },
+    { 0U, 0x2fU },
+    { 0U, 0xd9U },
+    { 4U, 0x92U },
+    { 4U, 0xb9U },
+    { 4U, 0xd7U },
+    { 48U, 0x95U },
+    { 48U, 0xbcU },
+    { 55U, 0xbfU },
+    { 56U, 0x9fU },
+    { 57U, 0x8dU },
+    { 57U, 0x17U },
+    { 57U, 0x94U },
+    { 61U, 0x92U },
+    { 75U, 0xdaU },
+    { 77U, 0x95U },
+    { 82U, 0xdfU },
+    { 84U, 0x9fU },
+    { 86U, 0x80U },
+    { 86U, 0x14U },
+    { 86U, 0x94U },
+    { 86U, 0xacU },
+    { 86U, 0x1aU },
+    { 86U, 0xbbU },
+    { 86U, 0xcaU },
+    { 86U, 0x2fU },
+    { 86U, 0xd9U },
+    { 90U, 0x92U },
+    { 90U, 0xb9U },
+    { 90U, 0xd7U },
+    { 160U, 0xdaU },
+    { 161U, 0xbcU },
+    { 162U, 0x95U },
+    { 167U, 0xdfU },
+    { 168U, 0xbfU },
+    { 169U, 0x9fU },
+    { 171U, 0x8dU },
+    { 171U, 0x10U },
+    { 171U, 0x94U },
+    { 171U, 0xa3U },
+    { 171U, 0x15U },
+    { 171U, 0xbbU },
+    { 171U, 0xc7U },
+    { 171U, 0x2aU },
+    { 171U, 0xd9U },
+    { 175U, 0x92U },
+    { 175U, 0xb9U },
+    { 175U, 0xd7U },
+    { 218U, 0xbcU },
+    { 219U, 0x95U },
+    { 225U, 0xbfU },
+    { 226U, 0x9fU },
+    { 228U, 0x83U },
+    { 228U, 0x15U },
+    { 228U, 0x94U },
+    { 232U, 0x92U },
+    { 245U, 0xdaU },
+    { 247U, 0x95U },
+    { 252U, 0xdfU },
+    { 254U, 0x9fU },
+    { 256U, 0x8dU },
+    { 256U, 0x10U },
+    { 256U, 0x94U },
+    { 256U, 0xa3U },
+    { 256U, 0x15U },
+    { 256U, 0xbbU },
+    { 256U, 0xc7U },
+    { 256U, 0x2aU },
+    { 256U, 0xd9U },
+    { 260U, 0x92U },
+    { 260U, 0xb9U },
+    { 260U, 0xd7U },
+    { 331U, 0xbcU },
+    { 331U, 0xdaU },
+    { 332U, 0x95U },
+    { 338U, 0xdfU },
+    { 339U, 0x9fU },
+    { 339U, 0xbfU },
+    { 341U, 0x82U },
+    { 341U, 0x0eU },
+    { 341U, 0x94U },
+    { 341U, 0xadU },
+    { 341U, 0x11U },
+    { 341U, 0xbbU },
+    { 341U, 0xc7U },
+    { 341U, 0x35U },
+    { 341U, 0xd9U },
+    { 345U, 0x92U },
+    { 345U, 0xb9U },
+    { 345U, 0xd7U },
+    { 416U, 0xdaU },
+    { 417U, 0xbcU },
+    { 418U, 0x95U },
+    { 423U, 0xdfU },
+    { 424U, 0xbfU },
+    { 425U, 0x9fU },
+    { 426U, 0x82U },
+    { 426U, 0x0eU },
+    { 426U, 0x94U },
+    { 426U, 0xadU },
+    { 426U, 0x11U },
+    { 426U, 0xbbU },
+    { 426U, 0xc7U },
+    { 426U, 0x35U },
+    { 426U, 0xd9U },
+    { 430U, 0x92U },
+    { 430U, 0xb9U },
+    { 430U, 0xd7U },
+    { 473U, 0xbcU },
+    { 473U, 0xdaU },
+    { 474U, 0x95U },
+    { 480U, 0xdfU },
+    { 481U, 0x9fU },
+    { 481U, 0xbfU },
+    { 483U, 0x82U },
+    { 483U, 0x0eU },
+    { 483U, 0x94U },
+    { 483U, 0xadU },
+    { 483U, 0x11U },
+    { 483U, 0xbbU },
+    { 483U, 0xc7U },
+    { 483U, 0x35U },
+    { 483U, 0xd9U },
+    { 487U, 0x92U },
+    { 487U, 0xb9U },
+    { 487U, 0xd7U },
+    { 558U, 0xdaU },
+    { 559U, 0x95U },
+    { 559U, 0xbcU },
+    { 565U, 0xdfU },
+    { 566U, 0xbfU },
+    { 567U, 0x9fU },
+    { 568U, 0x82U },
+    { 568U, 0x0eU },
+    { 568U, 0x94U },
+    { 568U, 0xadU },
+    { 568U, 0x11U },
+    { 568U, 0xbbU },
+    { 568U, 0xc7U },
+    { 568U, 0x35U },
+    { 568U, 0xd9U },
+    { 572U, 0x92U },
+    { 572U, 0xb9U },
+    { 572U, 0xd7U },
+    { 927U, 0xdaU },
+    { 928U, 0xbcU },
+    { 929U, 0x95U },
+    { 934U, 0xdfU },
+    { 935U, 0xbfU },
+    { 936U, 0x9fU },
+    { 1023U, 0x9fU },
+    { 1023U, 0xbfU },
+    { 1023U, 0xdfU },
+    { 1023U, 0xffU },
+    { 1023U, 0x9fU },
+    { 1023U, 0xbfU },
+    { 1023U, 0xdfU },
+    { 1023U, 0xffU },
+};
+#endif
diff --git a/examples/doebel/APPROVED.json b/examples/doebel/APPROVED.json
new file mode 100644
index 0000000..8a6437a
--- /dev/null
+++ b/examples/doebel/APPROVED.json
@@ -0,0 +1,24 @@
+{
+  "listening_approval": "Chad heard and approved DOEBEL-HOST.WAV on 2026-10-25; requested optional libtandy example",
+  "native_status": "passed normal completion, Escape cleanup and timer restoration on emulated Tandy HX; see NATIVE.json",
+  "publication": "approved by Chad on 2026-10-25",
+  "reference_wav_sha256": "9bd189015904bda25c5e75dff501696a7641934bb3ffeec87e3278f719d00b0d",
+  "reference_trace_sha256": "7d36113c4de4a210990410ddc2804a450a25fa419677f3dbb9c21213124a080c",
+  "per_note_audit_sha256": "d2de6d6634df6d537b78c4143e8c098f9dd46a3667b1e13f9fa8152876c3e6ae",
+  "score_json_sha256": "f1d913b8a3ef83cb692dbadd20341470469295632e4f1f7bb2204f89fcf47661",
+  "vgm_sha256": "2e495869bf4712937bfc296dc7be192147527cbc43a5f284f0867859779ebff3",
+  "frames": 1023,
+  "service_hz": 240,
+  "notes": [
+    10,
+    8,
+    8
+  ],
+  "gain": 0.18,
+  "native_attenuation": [
+    2,
+    9,
+    7
+  ],
+  "psg_writes": 173
+}
diff --git a/examples/doebel/DOEBEL.H b/examples/doebel/DOEBEL.H
new file mode 100644
index 0000000..5232afd
--- /dev/null
+++ b/examples/doebel/DOEBEL.H
@@ -0,0 +1,50 @@
+/* Optional PSG reduction of the referenced Evil Jingle opening.
+ * Musical attribution and usage: README.md.
+ * Generated from editable DOEBEL.json; developer-only generator.
+ */
+#ifndef DOEBEL_SCORE_H
+#define DOEBEL_SCORE_H
+#include "lt_score.h"
+#define DOEBEL_SERVICE_HZ 240U
+#define DOEBEL_END_TICK 2304U
+static const lt_score_note doebel_0[] = {
+    { 0U, 128U, 320U }, /* M01 F4 */
+    { 128U, 192U, 381U }, /* M02 D4 */
+    { 192U, 384U, 320U }, /* M03 F4 */
+    { 384U, 512U, 269U }, /* M04 G#4 */
+    { 512U, 576U, 339U }, /* M05 E4 */
+    { 576U, 768U, 269U }, /* M06 G#4 */
+    { 768U, 960U, 226U }, /* M07 B4 */
+    { 960U, 1088U, 226U }, /* M08 B4 */
+    { 1088U, 1280U, 226U }, /* M09 B4 */
+    { 1280U, 2112U, 226U }, /* M10 B4 */
+};
+static const lt_score_note doebel_1[] = {
+    { 0U, 128U, 428U }, /* H01 C4 */
+    { 192U, 384U, 428U }, /* H02 C4 */
+    { 384U, 512U, 339U }, /* H03 E4 */
+    { 576U, 768U, 339U }, /* H04 E4 */
+    { 768U, 960U, 285U }, /* H05 G4 */
+    { 960U, 1088U, 285U }, /* H06 G4 */
+    { 1088U, 1280U, 285U }, /* H07 G4 */
+    { 1280U, 2112U, 285U }, /* H08 G4 */
+};
+static const lt_score_note doebel_2[] = {
+    { 0U, 192U, 762U }, /* B01 D3 */
+    { 192U, 384U, 762U }, /* B02 D3 */
+    { 384U, 576U, 679U }, /* B03 E3 */
+    { 576U, 768U, 679U }, /* B04 E3 */
+    { 768U, 960U, 855U }, /* B05 C3 */
+    { 960U, 1088U, 855U }, /* B06 C3 */
+    { 1088U, 1280U, 855U }, /* B07 C3 */
+    { 1280U, 2112U, 855U }, /* B08 C3 */
+};
+static const lt_score doebel_score = {
+    LTSCORE_VERSION, 4U, 192U, 2112U, 2304U, 355030UL,
+    { doebel_0, doebel_1, doebel_2 },
+    { 10U, 8U, 8U },
+    { 2U, 9U, 7U },
+    { 4U, 6U, 8U },
+    0, 0U, 0, 0U
+};
+#endif
diff --git a/examples/doebel/DOEBEL.VGM b/examples/doebel/DOEBEL.VGM
new file mode 100644
index 0000000..fd128a2
Binary files /dev/null and b/examples/doebel/DOEBEL.VGM differ
diff --git a/examples/doebel/DOEBEL.json b/examples/doebel/DOEBEL.json
new file mode 100644
index 0000000..b856539
--- /dev/null
+++ b/examples/doebel/DOEBEL.json
@@ -0,0 +1,75 @@
+{
+  "title": "Doebelinschmirtz Incorporated — private PSG sketch",
+  "status": "LOCAL DEVELOPER AUDITION; native testing and explicit publication approval pending",
+  "reference": {
+    "title": "Evil Jingle (from Phineas and Ferb), opening measures 1–3",
+    "publisher_preview": "https://www.musicnotes.com/sheetmusic/sheet-music-boss/evil-jingle/MN0202127",
+    "preview_image": "https://www.musicnotes.com/product/image/MN0202127/large",
+    "arranger_page": "https://sheetmusicboss.com/2019/10/21/evil-jingle-from-phineas-and-ferb-piano-tutorial/",
+    "credit": "Words/music credited on preview to Danny Jacob, Jeff Marsh, Jon Barry, Zac Moncrief, Dan Povenmire and J.G. Orrantia; piano arrangement Andrew Wrangell; edited Samuel Dickenson.",
+    "scope": "Melody transcribed from the visible licensed opening preview. Three-tone reduction, approximate 2:1 swing and PSG articulation are arrangement decisions, not an exact recording recreation. No reference recording or score image is distributed."
+  },
+  "ppq": 192,
+  "tempo_us": 355030,
+  "tempo_bpm_reference": 169,
+  "psg_clock_hz": 3579545,
+  "service_hz": 240,
+  "one_shot_end_tick": 2304,
+  "silent_loop_start_tick": 2112,
+  "noise": "muted",
+  "pc_speaker": "unused",
+  "master_linear_gain": 0.18,
+  "normalization": "none; all stems and mix use identical gain",
+  "voices": [
+    {
+      "channel": 0,
+      "role": "reference melody",
+      "attenuation": 2,
+      "release_gap_ticks": 4,
+      "notes": [
+        {"id":"M01","start":0,"end":128,"pitch":"F4","reference":"m1 beat1, swung eighth"},
+        {"id":"M02","start":128,"end":192,"pitch":"D4","reference":"m1 offbeat1, swung eighth"},
+        {"id":"M03","start":192,"end":384,"pitch":"F4","reference":"m1 beat2, quarter"},
+        {"id":"M04","start":384,"end":512,"pitch":"G#4","reference":"m1 beat3, swung eighth, written sharp"},
+        {"id":"M05","start":512,"end":576,"pitch":"E4","reference":"m1 offbeat3, swung eighth"},
+        {"id":"M06","start":576,"end":768,"pitch":"G#4","reference":"m1 beat4, quarter"},
+        {"id":"M07","start":768,"end":960,"pitch":"B4","reference":"m2 beat1, quarter"},
+        {"id":"M08","start":960,"end":1088,"pitch":"B4","reference":"m2 beat2, swung eighth"},
+        {"id":"M09","start":1088,"end":1280,"pitch":"B4","reference":"m2 offbeat2 tied through beat3, combined as one event"},
+        {"id":"M10","start":1280,"end":2112,"pitch":"B4","reference":"m2 offbeat3 tied into m3 dotted half; one event, final beat rests"}
+      ]
+    },
+    {
+      "channel": 1,
+      "role": "reduced inner harmony; omissions intentional",
+      "attenuation": 9,
+      "release_gap_ticks": 6,
+      "notes": [
+        {"id":"H01","start":0,"end":128,"pitch":"C4"},
+        {"id":"H02","start":192,"end":384,"pitch":"C4"},
+        {"id":"H03","start":384,"end":512,"pitch":"E4"},
+        {"id":"H04","start":576,"end":768,"pitch":"E4"},
+        {"id":"H05","start":768,"end":960,"pitch":"G4"},
+        {"id":"H06","start":960,"end":1088,"pitch":"G4"},
+        {"id":"H07","start":1088,"end":1280,"pitch":"G4"},
+        {"id":"H08","start":1280,"end":2112,"pitch":"G4"}
+      ]
+    },
+    {
+      "channel": 2,
+      "role": "reference bass D2/E2/C2 raised one octave for PSG range",
+      "attenuation": 7,
+      "release_gap_ticks": 8,
+      "notes": [
+        {"id":"B01","start":0,"end":192,"pitch":"D3"},
+        {"id":"B02","start":192,"end":384,"pitch":"D3"},
+        {"id":"B03","start":384,"end":576,"pitch":"E3"},
+        {"id":"B04","start":576,"end":768,"pitch":"E3"},
+        {"id":"B05","start":768,"end":960,"pitch":"C3"},
+        {"id":"B06","start":960,"end":1088,"pitch":"C3"},
+        {"id":"B07","start":1088,"end":1280,"pitch":"C3"},
+        {"id":"B08","start":1280,"end":2112,"pitch":"C3"}
+      ]
+    }
+  ]
+}
diff --git a/examples/doebel/HOSTCHECK.json b/examples/doebel/HOSTCHECK.json
new file mode 100644
index 0000000..d273932
--- /dev/null
+++ b/examples/doebel/HOSTCHECK.json
@@ -0,0 +1,56 @@
+{
+  "status": "PASS: host checks only; no native/hardware/audible qualification",
+  "reference": {
+    "title": "Evil Jingle (from Phineas and Ferb), opening measures 1\u20133",
+    "publisher_preview": "https://www.musicnotes.com/sheetmusic/sheet-music-boss/evil-jingle/MN0202127",
+    "preview_image": "https://www.musicnotes.com/product/image/MN0202127/large",
+    "arranger_page": "https://sheetmusicboss.com/2019/10/21/evil-jingle-from-phineas-and-ferb-piano-tutorial/",
+    "credit": "Words/music credited on preview to Danny Jacob, Jeff Marsh, Jon Barry, Zac Moncrief, Dan Povenmire and J.G. Orrantia; piano arrangement Andrew Wrangell; edited Samuel Dickenson.",
+    "scope": "Melody transcribed from the visible licensed opening preview. Three-tone reduction, approximate 2:1 swing and PSG articulation are arrangement decisions, not an exact recording recreation. No reference recording or score image is distributed."
+  },
+  "libtandy_commit": "5d7036b9cdd23be9a0a3be7e9bc53c81680b055d",
+  "core_files": {
+    "lt_chip.c": "277505ef3f6c0eaa6e0aa51c1f7577f6420bb25c0b33726431c7413fd9998148",
+    "lt_audio.c": "c0869860a031f8ced684725eb9464c2fd987f61ac9952a826fdbe41e3394c688",
+    "lt_score.c": "e05088bde51a3b9ac5227993c424a40b6844035136068a04c23e1d85f729e737"
+  },
+  "sample_rate": 44100,
+  "duration_seconds": 4.512517006802721,
+  "service_hz": 240,
+  "score_ticks_per_second": 541,
+  "scheduler_phase_step": 147729,
+  "host_model": "8x oversampled ideal square waves, 2 dB PSG attenuation steps, mono sum; no analog filtering, speaker or noise",
+  "master_linear_gain": 0.18,
+  "normalization": "none",
+  "mix_peak": 0.17214770108816962,
+  "mix_peak_dbfs": -15.281975452376834,
+  "mix_rms": 0.10714142758052447,
+  "per_voice_peak": [
+    0.11357232200643479,
+    0.02266065741229501,
+    0.035914721669439834
+  ],
+  "per_voice_rms": [
+    0.099524136289553,
+    0.01936245481735165,
+    0.03172907993812419
+  ],
+  "note_count": [
+    10,
+    8,
+    8
+  ],
+  "checked_notes": 26,
+  "all_notes_passed": true,
+  "clipped_samples": 0,
+  "final_attenuation": [
+    15,
+    15,
+    15,
+    15
+  ],
+  "silent_tail_seconds": 0.25,
+  "vgm_stream_matches_trace": true,
+  "vgm_loop": false,
+  "publication": "NOT APPROVED; native test and explicit publication approval required"
+}
diff --git a/examples/doebel/NATIVE.json b/examples/doebel/NATIVE.json
new file mode 100644
index 0000000..23f938e
--- /dev/null
+++ b/examples/doebel/NATIVE.json
@@ -0,0 +1,54 @@
+{
+  "complete": true,
+  "date": "2026-10-25",
+  "scope": [
+    "normal completion",
+    "Escape cleanup",
+    "IRQ0 and timer restoration"
+  ],
+  "machine": {
+    "emulator": "86Box, local fixed build",
+    "emulator_sha256": "047477bb6f5d8681e08d6d5587aaab4285800c2f4efbb41549ccf75285974b1c",
+    "model": "Tandy 1000 HX",
+    "cpu": "8088",
+    "cpu_hz": 7159092,
+    "memory_kib": 640,
+    "dos": "MS-DOS 6.22"
+  },
+  "executable": {
+    "name": "DOEBEL.EXE",
+    "bytes": 14826,
+    "sha256": "a3857b85df56b2ff7d031916852f58ec9f64ac3e06bd1296d06b7f8d139026a9"
+  },
+  "before_irq0_vector_bytes": "a5fe00f0",
+  "normal": {
+    "exit_status": 0,
+    "active_irq0_vector_bytes": "e021d00e",
+    "bios_ticks_including_load": 95,
+    "restored": {
+      "irq0_vector": "a5fe00f0",
+      "matches_before": true,
+      "pit_counter": 54256,
+      "bios_ticks_over_approx_0_31_seconds": 6
+    },
+    "output": "Doebelinschmirtz Incorporated - optional PSG example\r\nOne jingle; Escape cancels. Use exclusive foreground Tandy DOS.\r\nDOEBEL: stopped, PSG muted\r\n"
+  },
+  "escape": {
+    "exit_status": 0,
+    "active_irq0_vector_bytes": "e021d00e",
+    "bios_ticks_from_active_playback": 8,
+    "restored": {
+      "irq0_vector": "a5fe00f0",
+      "matches_before": true,
+      "pit_counter": 28320,
+      "bios_ticks_over_approx_0_31_seconds": 6
+    },
+    "output": "Doebelinschmirtz Incorporated - optional PSG example\r\nOne jingle; Escape cancels. Use exclusive foreground Tandy DOS.\r\nDOEBEL: stopped, PSG muted\r\n"
+  },
+  "shared_lease_acquired": true,
+  "owned_child_stopped": true,
+  "shared_lease_released": true,
+  "physical_hardware_test": false,
+  "native_audio_capture": false,
+  "publication": "approved by Chad on 2026-10-25"
+}
diff --git a/examples/doebel/NOTES.csv b/examples/doebel/NOTES.csv
new file mode 100644
index 0000000..16b690c
--- /dev/null
+++ b/examples/doebel/NOTES.csv
@@ -0,0 +1,27 @@
+id,channel,pitch,start_tick,end_tick,frame,seconds,period,actual_hz,cents_error,attack_attenuation,attack_rms,transitions_35ms,passed
+M01,0,F4,0,128,0,0.0,320,349.5649,1.668,4,0.09542386,28,True
+M02,0,D4,128,192,57,0.2375,381,293.5979,-0.395,4,0.09552045,22,True
+M03,0,F4,192,384,86,0.358333,320,349.5649,1.668,4,0.09540569,28,True
+M04,0,G#4,384,512,171,0.7125,269,415.8393,2.227,4,0.09520551,34,True
+M05,0,E4,512,576,228,0.95,339,329.9728,1.812,4,0.0954681,25,True
+M06,0,G#4,576,768,256,1.066667,269,415.8393,2.227,4,0.0955051,33,True
+M07,0,B4,768,960,341,1.420833,226,494.9592,3.767,4,0.09521158,39,True
+M08,0,B4,960,1088,426,1.775,226,494.9592,3.767,4,0.0952905,39,True
+M09,0,B4,1088,1280,483,2.0125,226,494.9592,3.767,4,0.09521091,40,True
+M10,0,B4,1280,2112,568,2.366667,226,494.9592,3.767,4,0.09520987,38,True
+H01,1,C4,0,128,0,0.0,428,261.357,-1.778,11,0.01906232,20,True
+H02,1,C4,192,384,86,0.358333,428,261.357,-1.778,11,0.01906209,20,True
+H03,1,E4,384,512,171,0.7125,339,329.9728,1.812,11,0.01904457,25,True
+H04,1,E4,576,768,256,1.066667,339,329.9728,1.812,11,0.01904828,26,True
+H05,1,G4,768,960,341,1.420833,285,392.494,2.2,11,0.01902777,31,True
+H06,1,G4,960,1088,426,1.775,285,392.494,2.2,11,0.01903598,31,True
+H07,1,G4,1088,1280,483,2.0125,285,392.494,2.2,11,0.01902612,30,True
+H08,1,G4,1280,2112,568,2.366667,285,392.494,2.2,11,0.01902885,30,True
+B01,2,D3,0,192,0,0.0,762,146.7989,-0.395,9,0.03026659,12,True
+B02,2,D3,192,384,86,0.358333,762,146.7989,-0.395,9,0.03026432,12,True
+B03,2,E3,384,576,171,0.7125,679,164.7434,-0.739,9,0.03026333,13,True
+B04,2,E3,576,768,256,1.066667,679,164.7434,-0.739,9,0.03025316,14,True
+B05,2,C3,768,960,341,1.420833,855,130.8313,0.245,9,0.03027795,10,True
+B06,2,C3,960,1088,426,1.775,855,130.8313,0.245,9,0.03028626,10,True
+B07,2,C3,1088,1280,483,2.0125,855,130.8313,0.245,9,0.03028005,10,True
+B08,2,C3,1280,2112,568,2.366667,855,130.8313,0.245,9,0.03028005,10,True
diff --git a/examples/doebel/README.md b/examples/doebel/README.md
new file mode 100644
index 0000000..8f2f272
--- /dev/null
+++ b/examples/doebel/README.md
@@ -0,0 +1,78 @@
+# Doebelinschmirtz Incorporated
+
+An optional three-tone PSG rendition of the recognizable *Evil Jingle* from
+*Phineas and Ferb*, for Chad's “Doebelinschmirtz Incorporated” joke. It uses
+the existing `lt_score` API. Noise and PC speaker are unused.
+
+The melody follows the opening of the [licensed piano score preview](https://www.musicnotes.com/sheetmusic/sheet-music-boss/evil-jingle/MN0202127),
+arranged by Andrew Wrangell / Sheet Music Boss, edited by Samuel Dickenson.
+The preview credits Danny Jacob, Jeff Marsh, Jon Barry, Zac Moncrief,
+Dan Povenmire and J.G. Orrantia. This is a reduction of their recognizable
+tune, not an original composition. Musical rights remain with their owners;
+the library and playback code keep their existing MIT licenses.
+
+## Play or use the score
+
+Build from the repository root with the normal developer toolchain:
+
+```powershell
+python tools/build.py --target dos --watcom C:/WATCOM
+```
+
+Run `build/dos/DOEBEL.EXE` explicitly in exclusive foreground Tandy DOS.
+It plays once, mutes/releases the PSG and restores the BIOS timer. Escape
+cancels. It uses the existing `lt_tick_dos` adapter at nominal 240 Hz
+(PIT divisor 4,972, about 239.9803 Hz). No startup installation or speaker
+access is involved. Normal completion and Escape/timer cleanup passed on an
+emulated Tandy HX; see [the native receipt](NATIVE.json).
+
+`DOEBEL.H` is the ready-to-compile static score; `DOEBEL.VGM` is a ready
+one-shot PSG stream for an existing compatible VGM player. Neither needs a
+generator or Python on the playback machine. In an application that already
+owns the audio handle and update cadence:
+
+```c
+#include "DOEBEL.H"
+
+lt_score_init(&music, &audio);
+lt_score_start(&music, &doebel_score, DOEBEL_SERVICE_HZ, 0, 0);
+/* Once per existing 240-Hz update, before the silent loop boundary: */
+if (music.phase + music.step >= ((lta_u32)DOEBEL_END_TICK << 16))
+    lt_score_stop(&music);
+else
+    lt_score_tick(&music);
+```
+
+The caller owns all four PSG channels, serialization and timing. See
+[`../doebel_demo.c`](../doebel_demo.c) for setup, errors and cleanup. Do not
+install another timer in an app that already has one.
+
+## Edit and verify
+
+`DOEBEL.json` is the unchanged approved editable score: 10 melody, 8 harmony
+and 8 bass events. It retains 192 PPQ, 355,030 microseconds/quarter, 2:1 swing,
+the tied ending and attenuation levels 2/9/7. The bass is raised an octave to
+fit PSG range. The checked-in header preserves those notes and envelope gaps.
+
+`generate.py --write` rebuilds only the header after deliberate edits;
+`generate.py --check` checks it without writing. This is a developer tool.
+The frozen `APPROVED.H` register fixture and `NOTES.csv` per-note audit are
+from the host audition Chad heard and approved on 2026-10-25. The host suite
+compares every actual PSG byte and service frame against that fixture,
+including repeated attacks and the ending mute/release. `APPROVED.json`
+retains the reference WAV and audit hashes; `HOSTCHECK.json` is the original
+numerical receipt.
+
+The approved WAV is a 4.512517-second host approximation, with fixed master
+gain 0.18, identical-gain stems, no normalization and a peak of -15.28 dBFS.
+The master gain is a host-rendering factor; native PSG attenuation remains
+2/9/7 with the existing score envelopes. The approximation uses ideal square
+waves and does not model analog filtering or speaker response. No gain,
+notes, timing or balance changes are introduced by this example.
+
+Listening approval covers the host sound. The short native normal-completion,
+Escape and timer-restoration checks passed using the shared emulator lease.
+Physical hardware and native audio capture are not qualified. Chad approved
+publication on 2026-10-25. Status text in the unchanged
+score JSON is historical audition metadata; this README and the validation
+receipts describe current acceptance.
diff --git a/examples/doebel/VALIDATION.md b/examples/doebel/VALIDATION.md
new file mode 100644
index 0000000..fd6ffb6
--- /dev/null
+++ b/examples/doebel/VALIDATION.md
@@ -0,0 +1,47 @@
+# Local validation, 2026-10-25
+
+Base: libtandy main `5d7036b9cdd23be9a0a3be7e9bc53c81680b055d`.
+Chad listened to and approved the host sound, then requested this optional
+example. Chad approved publication of the tested example on 2026-10-25.
+
+- The editable score, VGM and 26-row per-note audit are byte-identical to
+  the approved assets. Header changes are comments only; all events,
+  periods, tempo, levels and release gaps are unchanged.
+- Re-rendering with this checkout's unchanged `lt_chip`, `lt_audio` and
+  `lt_score` produces the identical WAV, register trace, audit and VGM.
+  Approved WAV SHA-256:
+  `9bd189015904bda25c5e75dff501696a7641934bb3ffeec87e3278f719d00b0d`.
+- The normal host suite passes all 12 test programs, including the new
+  regression comparing 173 actual PSG writes and their service frames to
+  the frozen approved trace. The generator's read-only header check passes.
+- The normal DOS build completed all 40 steps with Open Watcom's 8086
+  small-model flags and warnings treated as errors. Native acceptance then
+  exposed an output-name collision: the regression overwrote `DOEBEL.EXE`.
+  The regression now builds as `DBSCORE.EXE`; its old 18,488-byte binary was
+  preserved. Only the player was rebuilt with the same normal compiler
+  recipe, without repeating host suites. The actual `DOEBEL.EXE` is 14,826
+  bytes, SHA-256
+  `a3857b85df56b2ff7d031916852f58ec9f64ac3e06bd1296d06b7f8d139026a9`.
+- Both requested short native checks passed on an emulated Tandy 1000 HX,
+  8088 at 7.159092 MHz, 640 KiB, MS-DOS 6.22. Normal completion returned
+  successfully; Escape stopped active playback within eight BIOS ticks.
+  Both paths reported PSG mute and restored the original IRQ0 vector
+  `F000:FEA5`. Post-return PIT counters were in BIOS range, and the BIOS
+  clock advanced six ticks in each approximate 0.31-second observation.
+  [NATIVE.json](NATIVE.json) records the results and executable identity.
+- The shared lease was acquired after the preceding owner finished. The
+  private child was stopped before the lease was released. Physical hardware
+  and native audio capture remain outside this acceptance check.
+
+Commands run from the repository root:
+
+```powershell
+python examples/doebel/generate.py --check
+python tools/build.py --target host --gcc-launcher C:/Users/chad/Documents/Codex/toolchains/gcc-ucrt64.py --runtime-bin C:/msys64/ucrt64/bin
+python tools/build.py --target dos --watcom C:/WATCOM
+git diff --check
+```
+
+The generated header is 1,739 bytes of source text; its 26 `lt_score_note`
+events occupy 156 bytes of note data. The ready one-shot VGM is 612 bytes.
+Build outputs and full compiler logs stay in ignored `build/` directories.
diff --git a/examples/doebel/generate.py b/examples/doebel/generate.py
new file mode 100644
index 0000000..3dacca3
--- /dev/null
+++ b/examples/doebel/generate.py
@@ -0,0 +1,71 @@
+"""Developer-only score-header regeneration; playback never needs Python.
+
+python examples/doebel/generate.py --check
+python examples/doebel/generate.py --write   # after intentional score edits
+The approved trace/audit is a frozen listening reference, not regenerated.
+"""
+import argparse
+import json
+import math
+from pathlib import Path
+import re
+
+HERE = Path(__file__).resolve().parent
+
+
+def render():
+    score = json.loads((HERE / 'DOEBEL.json').read_text(encoding='utf-8'))
+    result = ['/* Optional PSG reduction of the referenced Evil Jingle opening.',
+              ' * Musical attribution and usage: README.md.',
+              ' * Generated from editable DOEBEL.json; developer-only generator.',
+              ' */', '#ifndef DOEBEL_SCORE_H', '#define DOEBEL_SCORE_H',
+              '#include "lt_score.h"',
+              '#define DOEBEL_SERVICE_HZ %uU' % score['service_hz'],
+              '#define DOEBEL_END_TICK %uU' % score['one_shot_end_tick']]
+    for voice in score['voices']:
+        result.append('static const lt_score_note doebel_%u[] = {' % voice['channel'])
+        previous = 0
+        for note in voice['notes']:
+            match = re.fullmatch(r'([A-G])(#?)([0-8])', note['pitch'])
+            if not match:
+                raise ValueError(note['pitch'])
+            midi = (int(match[3])+1)*12 + dict(C=0, D=2, E=4, F=5,
+                    G=7, A=9, B=11)[match[1]] + bool(match[2])
+            hz = 440 * 2 ** ((midi-69)/12)
+            period = math.floor(score['psg_clock_hz']/(32*hz)+.5)
+            if not (1 <= period <= 1023 and previous <= note['start'] <
+                    note['end'] <= score['silent_loop_start_tick']):
+                raise ValueError(note)
+            previous = note['end']
+            result.append('    { %uU, %uU, %uU }, /* %s %s */' % (
+                note['start'], note['end'], period, note['id'], note['pitch']))
+        result.append('};')
+    result += ['static const lt_score doebel_score = {',
+               '    LTSCORE_VERSION, 4U, %uU, %uU, %uU, %uUL,' % (
+                   score['ppq'], score['silent_loop_start_tick'],
+                   score['one_shot_end_tick'], score['tempo_us']),
+               '    { doebel_0, doebel_1, doebel_2 },']
+    for field in ('notes', 'attenuation', 'release_gap_ticks'):
+        values = [(len(v[field]) if field == 'notes' else v[field]) for v in score['voices']]
+        result.append('    { ' + ', '.join('%uU' % v for v in values) + ' },')
+    result += ['    0, 0U, 0, 0U', '};', '#endif', '']
+    return '\n'.join(result)
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    mode = parser.add_mutually_exclusive_group(required=True)
+    mode.add_argument('--check', action='store_true')
+    mode.add_argument('--write', action='store_true')
+    args = parser.parse_args()
+    expected = render()
+    path = HERE / 'DOEBEL.H'
+    if args.write:
+        path.write_bytes(expected.replace('\n', '\r\n').encode('ascii'))
+    elif path.read_text(encoding='ascii') != expected:
+        raise SystemExit('FAIL DOEBEL.H does not match editable score')
+    print('PASS editable Doebel score and checked-in header')
+
+
+if __name__ == '__main__':
+    main()
diff --git a/examples/doebel_demo.c b/examples/doebel_demo.c
new file mode 100644
index 0000000..d38b68f
--- /dev/null
+++ b/examples/doebel_demo.c
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: MIT */
+/* Optional DOS example; the referenced musical data has its own notice.
+ * Run DOEBEL.EXE explicitly in foreground Tandy DOS. Escape cancels.
+ * No video switch, startup hook, bank changes or PC-speaker access.
+ */
+#include <conio.h>
+#include <stdio.h>
+#include "lt_audio.h"
+#include "lt_score.h"
+#include "lt_tick_dos.h"
+#include "doebel/DOEBEL.H"
+
+extern void lt_dos_emit(void *context, lt_u8 byte);
+static lt_u16 psg_port = 0x00C0U;
+static lt_chip chip;
+static lta_handle audio;
+static lt_score_player music;
+static volatile unsigned finished, playback_error;
+
+/* Existing timer adapter, nominal 240 Hz (1,193,182 / 4,972 Hz).
+ * Keep the approved score's 240-Hz service contract and tempo unchanged. */
+#define DOEBEL_PIT_DIVISOR 4972U
+
+static void wait_for_interrupt(void);
+#pragma aux wait_for_interrupt = "hlt" modify exact []
+
+static void update(void *context)
+{
+    lta_status status;
+    (void)context;
+    if (finished) return;
+    if (music.phase + music.step >= (lta_u32)DOEBEL_END_TICK << 16) {
+        status = lt_score_stop(&music);
+        finished = 1U;
+    } else {
+        status = lt_score_tick(&music);
+    }
+    if (status != LTA_OK) {
+        playback_error = (unsigned)status;
+        finished = 1U;
+    }
+}
+
+int main(void)
+{
+    lta_request request;
+    int timer_open = 0;
+    int failed = 0;
+    puts("Doebelinschmirtz Incorporated - optional PSG example");
+    puts("One jingle; Escape cancels. Use exclusive foreground Tandy DOS.");
+    lt_init(&chip, lt_dos_emit, &psg_port);
+    if (lta_init(&audio, &chip, 1U) != LTA_OK) return 1;
+    lta_request_init(&request);
+    request.op = LTA_OP_ACQUIRE;
+    request.mask = 15U;
+    if (lta_command(&audio, &request) != LTA_OK) return 1;
+    if (lt_score_init(&music, &audio) != LTA_OK) {
+        failed = 1;
+    } else if (lttk_open(DOEBEL_PIT_DIVISOR, update, 0) != LTTK_OK) {
+        puts("DOEBEL: timer busy");
+        failed = 1;
+    } else {
+        timer_open = 1;
+        if (lt_score_start(&music, &doebel_score,
+                           DOEBEL_SERVICE_HZ, 0, 0) != LTA_OK) {
+            failed = 1;
+        } else {
+            lttk_run(1);
+            while (!finished) {
+                if (kbhit() && getch() == 27) break;
+                wait_for_interrupt();
+            }
+            lttk_run(0);
+        }
+        if (lt_score_stop(&music) != LTA_OK) failed = 1;
+    }
+    /* Work is stopped before foreground audio cleanup. Release mutes all
+     * owned channels; close restores the BIOS timer using the same adapter. */
+    lta_request_init(&request);
+    request.op = LTA_OP_RELEASE;
+    if (lta_command(&audio, &request) != LTA_OK) failed = 1;
+    if (timer_open && lttk_close() != LTTK_OK) failed = 1;
+    if (playback_error) failed = 1;
+    puts(failed ? "DOEBEL: playback/cleanup failed" : "DOEBEL: stopped, PSG muted");
+    return failed;
+}
diff --git a/tests/doebel_score_core.c b/tests/doebel_score_core.c
new file mode 100644
index 0000000..6a4f52b
--- /dev/null
+++ b/tests/doebel_score_core.c
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: MIT */
+/* Preserve the actual PSG writes/timing that generated Chad's approved WAV.
+ * The literal fixture is frozen from that audition, not regenerated from
+ * the candidate score. Musical data attribution: examples/doebel/README.md.
+ */
+#include <stdio.h>
+#include "lt_audio.h"
+#include "lt_score.h"
+#include "../examples/doebel/DOEBEL.H"
+#include "../examples/doebel/APPROVED.H"
+
+static lt_chip chip;
+static lta_handle audio;
+static lt_score_player music;
+static unsigned frame, index, failures;
+
+static void emit(void *context, lt_u8 byte)
+{
+    (void)context;
+    if (index >= DOEBEL_APPROVED_WRITES ||
+        doebel_approved[index].frame != frame ||
+        doebel_approved[index].byte != byte) {
+        ++failures;
+    }
+    ++index;
+}
+
+int main(void)
+{
+    lta_request request;
+    unsigned voice;
+    lt_init(&chip, emit, 0);
+    if (lta_init(&audio, &chip, 1U) != LTA_OK) return 1;
+    lta_request_init(&request);
+    request.op = LTA_OP_ACQUIRE;
+    request.mask = 15U;
+    if (lta_command(&audio, &request) != LTA_OK) return 2;
+    if (lt_score_init(&music, &audio) != LTA_OK) return 3;
+    if (lt_score_start(&music, &doebel_score,
+                       DOEBEL_SERVICE_HZ, 0, 0) != LTA_OK) return 4;
+    while (music.phase + music.step < (lta_u32)DOEBEL_END_TICK << 16) {
+        ++frame;
+        if (lt_score_tick(&music) != LTA_OK) return 5;
+    }
+    ++frame;
+    if (lt_score_stop(&music) != LTA_OK) return 6;
+    lta_request_init(&request);
+    request.op = LTA_OP_RELEASE;
+    if (lta_command(&audio, &request) != LTA_OK) return 7;
+    if (frame != 1023U || index != DOEBEL_APPROVED_WRITES) ++failures;
+    for (voice = 0U; voice < 4U; ++voice)
+        if (chip.attenuation[voice] != 15U || chip.owner[voice]) ++failures;
+    if (failures) {
+        printf("FAIL Doebel approved trace: %u differences\n", failures);
+        return 8;
+    }
+    puts("PASS Doebel approved PSG bytes, timing, levels and ending mute");
+    return 0;
+}
diff --git a/tools/build.py b/tools/build.py
index 6c820df..cb7182a 100644
--- a/tools/build.py
+++ b/tools/build.py
@@ -12,6 +12,7 @@
     'audio': ('audio_core', ['lt_chip', 'lt_audio']),
     'sfx': ('sfx_core', ['lt_chip', 'lt_audio', 'lt_sfx']),
     'score': ('score_core', ['lt_chip', 'lt_audio', 'lt_sfx', 'lt_score']),
+    'dbscore': ('doebel_score_core', ['lt_chip', 'lt_audio', 'lt_score']),
     'graphics': ('gfx_host', ['lt_gfx', 'lt_gfx_rows']),
     'surface': ('surface_core', ['lt_surface']),
     'time': ('time_core', ['lt_time']),
@@ -21,6 +22,9 @@
 }
 # DOS-only demos of the platform services: name -> sources.
 DOS_DEMOS = {
+    'DOEBEL': ['examples/doebel_demo.c', 'src/lt_chip.c',
+               'src/lt_audio.c', 'src/lt_score.c', 'adapters/lt_dos.c',
+               'adapters/lt_tick_dos.c'],
     'PAGEDEMO': ['examples/page_demo.c', 'src/lt_chip.c', 'src/lt_gfx.c',
                  'src/lt_event.c', 'adapters/lt_dos.c',
                  'adapters/lt_input_dos.c', 'adapters/lt_dos_app.c',
@@ -83,6 +87,9 @@ def run(argv, label):
             raise RuntimeError(label + ': ' + result.stdout + result.stderr)
         return result
 
+    run([sys.executable, ROOT / 'examples/doebel/generate.py', '--check'],
+        'doebel score data')
+
     if args.target == 'dos':
         watcom = args.watcom.resolve()
         if os.name == 'nt':