Fix bass sampler range and cover audible notes

README.md

@@ -21,7 +21,8 @@ source-timed comparisons. SheetSage2 extracts notes and beats; FluidSynth
 uses the full [FluidR3 GM bank](https://www.fluidsynth.org/wiki/GettingStarted/)
 for the selected instrument and drum kit, plus sampled electric
 guitar and fingered bass in clean and processed versions. The bass is shifted
-down one octave, with note starts and lengths preserved. A continuous-F0 synth
+down two octaves into the actual sample range, with note starts and lengths
+preserved. A continuous-F0 synth
 follows voice pitch and amplitude. The sampler uses full-size FreePats electric
 guitar and fingered bass SoundFonts, with FFmpeg compression, filtering,
 oversampled soft clipping, and a short guitar room echo in processed versions.

app.py

@@ -72,7 +72,7 @@ with gr.Blocks(title="Hum · напев в инструмент", css=CSS, theme
             go = gr.Button("Создать все варианты", variant="primary", size="lg")
             gr.HTML("""<div class='note'><b>Текущая цель:</b> один инструмент и
             приблизительно исходное время. Электрогитара и бас используют
-            записанные сэмплы; бас звучит октавой ниже. Обработанные версии
+            записанные сэмплы; бас звучит на две октавы ниже. Обработанные версии
             добавляют усиление и лёгкий эффект, но не новые ноты. Барабаны
             привязаны к долям SheetSage2. YuE2 может изменить
             длительность, добавить человеческие звуки или другие инструменты;

pipeline.py

@@ -20,6 +20,9 @@ YUE_PYTHON = Path(os.environ.get("HUM_YUE_PYTHON", "/opt/yue/bin/python"))
 SOUNDFONT_DIR = Path(os.environ.get("HUM_SOUNDFONTS", "/opt/soundfonts"))
 GM_SOUNDFONT = Path(os.environ.get("HUM_GM_SOUNDFONT",
                                 "/usr/share/sounds/sf2/FluidR3_GM.sf2"))
+# FreePats Finger Bass is silent over much of the voice-minus-one-octave
+# range; two octaves put the seen 54..68 melody into its audible 30..44 range.
+BASS_TRANSPOSE = -24
 SAMPLER_VARIANTS = (
     "instrument", "instrument_drums", "contour",
     "guitar_clean", "guitar_amp", "bass_clean", "bass_amp",
@@ -348,7 +351,7 @@ def generate_all(source: str, instrument: str, styles: dict[str, str], seed: int
                     "yue_requested": include_yue, "yue_timing": dict(yue_timing),
                     "errors": dict(errors), "complete": complete,
                     "source_timing_preserved": list(SAMPLER_VARIANTS),
-                    "bass_transpose_semitones": -12,
+                    "bass_transpose_semitones": BASS_TRANSPOSE,
                     "yue_vocal_absence_guaranteed": False,
                     "elapsed_seconds": round(time.monotonic() - began, 2)}
         return (*(outputs[name] for name in VARIANTS), str(melody_midi),
@@ -387,7 +390,7 @@ def generate_all(source: str, instrument: str, styles: dict[str, str], seed: int
         progress(.48, desc="Сэмплирую электрогитару и бас")
     for name, font_name, transpose, effect in (
         ("guitar_clean", "electric-clean.sf2", 0, "guitar"),
-        ("bass_clean", "finger-bass.sf2", -12, "bass"),
+        ("bass_clean", "finger-bass.sf2", BASS_TRANSPOSE, "bass"),
     ):
         try:
             raw, _ = render_preset(midi, folder, name, 0, duration, log,

test_sampler.py

@@ -10,6 +10,33 @@ from unittest.mock import patch
 
 
 class SamplerTest(unittest.TestCase):
+    def test_bass_font_sounds_at_both_ends_of_development_note_range(self):
+        import numpy as np
+        import pretty_midi
+        import soundfile as sf
+        from pipeline import BASS_TRANSPOSE, SOUNDFONT_DIR, render_preset
+
+        font = SOUNDFONT_DIR / "finger-bass.sf2"
+        if not font.is_file():
+            self.skipTest("Pinned FreePats bass SoundFont not installed")
+        # The seen development recording spans MIDI 54..68. Keep this tiny
+        # synthetic fixture separate from the source audio and its title.
+        with tempfile.TemporaryDirectory() as directory:
+            folder = Path(directory)
+            score = pretty_midi.PrettyMIDI()
+            voice = pretty_midi.Instrument(program=0)
+            voice.notes = [pretty_midi.Note(90, 54, .1, .35),
+                           pretty_midi.Note(90, 68, .6, .85)]
+            score.instruments.append(voice)
+            midi = folder / "notes.mid"
+            score.write(str(midi))
+            wav, _ = render_preset(midi, folder, "bass", 0, 1., folder / "log",
+                                   soundfont=font, transpose=BASS_TRANSPOSE)
+            audio, rate = sf.read(wav, dtype="float32", always_2d=True)
+            for start in (.12, .62):
+                span = audio[round(start * rate):round((start + .1) * rate)]
+                self.assertGreater(float(np.sqrt(np.mean(span**2))), .001)
+
     def test_optional_yue_does_not_reclassify_sampler_outputs_as_missing(self):
         import numpy as np
         import soundfile as sf
@@ -54,9 +81,9 @@ class SamplerTest(unittest.TestCase):
                 final = list(generate_all(str(wave), "Флейта", {}, 4096, True))[-1]
             self.assertEqual(final[-1]["errors"], {})
 
-    def test_bass_octave_preserves_note_times(self):
+    def test_bass_register_preserves_note_times(self):
         import pretty_midi
-        from pipeline import render_preset
+        from pipeline import BASS_TRANSPOSE, render_preset
 
         with tempfile.TemporaryDirectory() as directory:
             folder = Path(directory)
@@ -71,9 +98,9 @@ class SamplerTest(unittest.TestCase):
             original.write(str(source))
             with patch("pipeline.render_midi", return_value=folder / "bass.wav"):
                 _, path = render_preset(source, folder, "bass", 0, 1.,
-                                        folder / "log", transpose=-12)
+                                        folder / "log", transpose=BASS_TRANSPOSE)
             notes = pretty_midi.PrettyMIDI(str(path)).instruments[0].notes
-            self.assertEqual([n.pitch for n in notes], [48, 52])
+            self.assertEqual([n.pitch for n in notes], [36, 40])
             for before, after in zip(voice.notes, notes):
                 self.assertAlmostEqual(before.start, after.start, places=4)
                 self.assertAlmostEqual(before.end, after.end, places=4)