Add reference_pitch to Score and playback pipeline

Score(reference_pitch=415.0, temperament="meantone") renders an
entire piece at Baroque pitch with historical tuning. Flows through
to all .pitch() calls in both normal and legato renderers.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pytheory/play.py

@@ -1971,7 +1971,8 @@ def _render_notes_to_buf(notes, buf, samples_per_beat, total_samples,
                          filter_attack=0.01, filter_decay=0.3,
                          filter_sustain=0.0, filter_amount=0.0,
                          vel_to_filter=0.0, filter_q=0.707,
-                         synth_kwargs=None, temperament="equal"):
+                         synth_kwargs=None, temperament="equal",
+                         reference_pitch=440.0):
     """Render a list of Notes into an existing buffer at the correct positions."""
     import random as _rnd
 
@@ -2000,9 +2001,9 @@ def _render_notes_to_buf(notes, buf, samples_per_beat, total_samples,
             if n_samples > 0 and start >= 0:
                 # Get pitches
                 if hasattr(note.tone, 'tones'):
-                    pitches = [t.pitch(temperament=temperament) for t in note.tone.tones]
+                    pitches = [t.pitch(temperament=temperament, reference_pitch=reference_pitch) for t in note.tone.tones]
                 else:
-                    pitches = [note.tone.pitch(temperament=temperament)]
+                    pitches = [note.tone.pitch(temperament=temperament, reference_pitch=reference_pitch)]
                 # Render oscillators (pass synth_kwargs for FM etc.)
                 waves = [synth_fn(hz, n_samples=n_samples, **_skw)
                          for hz in pitches]
@@ -2088,7 +2089,7 @@ def _render_notes_to_buf(notes, buf, samples_per_beat, total_samples,
 def _render_legato_to_buf(notes, buf, samples_per_beat, total_samples,
                           synth_fn, envelope_tuple, volume, bpm,
                           glide_time=0.0, swing=0.0, tempo_map=None,
-                          temperament="equal"):
+                          temperament="equal", reference_pitch=440.0):
     """Render notes as one continuous waveform with pitch glide.
 
     Instead of rendering each note separately with its own envelope,
@@ -2118,9 +2119,9 @@ def _render_legato_to_buf(notes, buf, samples_per_beat, total_samples,
         vel = getattr(note, 'velocity', 100)
         if note.tone is not None:
             if hasattr(note.tone, 'tones'):
-                hz = note.tone.tones[0].pitch(temperament=temperament)
+                hz = note.tone.tones[0].pitch(temperament=temperament, reference_pitch=reference_pitch)
             else:
-                hz = note.tone.pitch(temperament=temperament)
+                hz = note.tone.pitch(temperament=temperament, reference_pitch=reference_pitch)
             events.append((start, end, hz, vel))
         else:
             events.append((start, end, 0, vel))  # rest
@@ -2239,13 +2240,14 @@ def render_score(score):
                 synth_kwargs["mod_ratio"] = part.fm_ratio
                 synth_kwargs["mod_index"] = part.fm_index
             _temperament = getattr(score, 'temperament', 'equal')
+            _ref_pitch = getattr(score, 'reference_pitch', 440.0)
             if part.legato:
                 _render_legato_to_buf(
                     part.notes, part_buf, samples_per_beat, total_samples,
                     synth_fn, env_tuple, part.volume, score.bpm,
                     glide_time=part.glide, swing=effective_swing,
                     tempo_map=tempo_map if has_tempo_changes else None,
-                    temperament=_temperament)
+                    temperament=_temperament, reference_pitch=_ref_pitch)
             else:
                 _render_notes_to_buf(
                     part.notes, part_buf, samples_per_beat, total_samples,
@@ -2265,7 +2267,8 @@ def render_score(score):
                     vel_to_filter=part.vel_to_filter,
                     filter_q=part.lowpass_q,
                     synth_kwargs=synth_kwargs,
-                    temperament=_temperament)
+                    temperament=_temperament,
+                    reference_pitch=_ref_pitch)
 
             # Apply effects — segmented if automation exists
             auto_points = part._get_automation_points()

pytheory/rhythm.py

@@ -2074,7 +2074,7 @@ class Score:
 
     def __init__(self, time_signature="4/4", bpm=120, swing: float = 0.0,
                  drum_humanize: float = 0.15, system: str = "western",
-                 temperament: str = "equal"):
+                 temperament: str = "equal", reference_pitch: float = 440.0):
         if isinstance(time_signature, str):
             self.time_signature = TimeSignature.from_string(time_signature)
         else:
@@ -2083,6 +2083,7 @@ class Score:
         self.swing = swing
         self.system = system
         self.temperament = temperament
+        self.reference_pitch = reference_pitch
         self._drum_humanize = drum_humanize
         self.notes: list[Note] = []
         self.parts: dict[str, Part] = {}