From d3e5d59f2aa0dffe41184f1ebba5d15e5ff2d892 Mon Sep 17 00:00:00 2001
From: hill <hill@hilll.dev>
Date: Wed, 23 Sep 2026 11:30:08 +0200
Subject: [PATCH] Mark an octave-repeating scale wider than an octave as not
 duplicating

AbstractOctaveRepeatingScale completes its steps to the next octave above
their sum, so steps wider than an octave make a pattern spanning two or
more octaves. The network was still marked octave-duplicating, and
realizing it moved the reference by single octaves into the middle of
that pattern, so the scale started an octave above its tonic:

    >>> sc = scale.OctaveRepeatingScale('c4', ['P5', 'P5'])
    >>> sc.pitches
    [<music21.pitch.Pitch C5>, <music21.pitch.Pitch G5>,
     <music21.pitch.Pitch D6>, <music21.pitch.Pitch C7>]

Mark the network octave-duplicating only when the completed pattern
spans one octave. A pattern of one octave builds exactly as before.
---
 music21/scale/__init__.py        | 11 ++++++-----
 music21/scale/test_scale_main.py |  7 ++++++-
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/music21/scale/__init__.py b/music21/scale/__init__.py
index ebb66478e..9dc898f0f 100644
--- a/music21/scale/__init__.py
+++ b/music21/scale/__init__.py
@@ -6,7 +6,7 @@
 #               Michael Scott Asato Cuthbert
 #               Jose Cabal-Ugaz
 #
-# Copyright:    Copyright © 2009-2011 Michael Scott Asato Cuthbert
+# Copyright:    Copyright © 2009-2026 Michael Scott Asato Cuthbert
 # License:      BSD, see license.txt
 # ------------------------------------------------------------------------------
 '''
@@ -1005,10 +1005,6 @@ def __init__(self, mode: t.Any = None, **keywords) -> None:
             mode = ['P8']
         self.buildNetwork(mode=mode)
 
-        # by definition, these are forced to be octave duplicating
-        # though, do to some intervals, duplication may not happen every oct
-        self.octaveDuplicating = True
-
     def buildNetwork(self, mode: t.Any = None) -> None:
         '''
         Here, mode is the list of intervals.
@@ -1022,6 +1018,11 @@ def buildNetwork(self, mode: t.Any = None) -> None:
         if iComplement is not None:
             mode.append(iComplement)
 
+        # steps wider than an octave complete a pattern spanning several
+        # octaves, which does not repeat every octave
+        span = intervalSum.semitones + (iComplement.semitones if iComplement else 0)
+        self.octaveDuplicating = span == 12
+
         self.tonicDegree = 1
         self._net = intervalNetwork.IntervalNetwork(mode,
                                                     octaveDuplicating=self.octaveDuplicating)
diff --git a/music21/scale/test_scale_main.py b/music21/scale/test_scale_main.py
index ded1bd6d9..1ccf36487 100644
--- a/music21/scale/test_scale_main.py
+++ b/music21/scale/test_scale_main.py
@@ -5,7 +5,7 @@
 # Authors:      Christopher Ariza
 #               Michael Scott Asato Cuthbert
 #
-# Copyright:    Copyright © 2010-2024 Michael Scott Asato Cuthbert
+# Copyright:    Copyright © 2010-2026 Michael Scott Asato Cuthbert
 # License:      BSD, see license.txt
 # ------------------------------------------------------------------------------
 from __future__ import annotations
@@ -233,6 +233,11 @@ def testBasic(self):
              <music21.pitch.Pitch F#5>],
  'notMatched': [<music21.pitch.Pitch C#5>, <music21.pitch.Pitch G#5>]}''', pformat(sc1.match(sc2)))
 
+    def testOctaveRepeatingScaleWiderThanAnOctave(self):
+        sc = scale.OctaveRepeatingScale('c4', ['P5', 'P5'])
+        self.assertEqual(self.pitchOut(sc.pitches), '[C4, G4, D5, C6]')
+        self.assertEqual(self.pitchOut(sc.getPitches('c3', 'c6')), '[D3, C4, G4, D5, C6]')
+
     def testCyclicalScales(self):
         sc = scale.CyclicalScale('c4', ['m2', 'm2'])