diff --git a/soundfile_backend.py b/soundfile_backend.py
new file mode 100644
index 0000000000..84667c488a
--- /dev/null
+++ b/soundfile_backend.py
@@ -0,0 +1,17 @@
+    """
+    with soundfile.SoundFile(filepath, "r") as file_:
+        if file_.format != "WAV" or normalize:
+            # When reading non-WAV formats (e.g. MP3) with normalize=True,
+            # use the native floating-point dtype for the subtype if available,
+            # falling back to float32. This ensures correct reading of files
+            # that require float64 precision (e.g. certain MP3 files with
+            # DOUBLE subtype). For integer subtypes, float32 is used for
+            # normalization.
+            subtype_dtype = _SUBTYPE2DTYPE.get(file_.subtype)
+            if subtype_dtype in ("float64",):
+                dtype = "float64"
+            else:
+                dtype = "float32"
+        elif file_.subtype not in _SUBTYPE2DTYPE:
+            raise ValueError(f"Unsupported subtype: {file_.subtype}")
+        else:
diff --git a/soundfile_backend_original.py b/soundfile_backend_original.py
new file mode 100644
index 0000000000..84667c488a
--- /dev/null
+++ b/soundfile_backend_original.py
@@ -0,0 +1,17 @@
+    """
+    with soundfile.SoundFile(filepath, "r") as file_:
+        if file_.format != "WAV" or normalize:
+            # When reading non-WAV formats (e.g. MP3) with normalize=True,
+            # use the native floating-point dtype for the subtype if available,
+            # falling back to float32. This ensures correct reading of files
+            # that require float64 precision (e.g. certain MP3 files with
+            # DOUBLE subtype). For integer subtypes, float32 is used for
+            # normalization.
+            subtype_dtype = _SUBTYPE2DTYPE.get(file_.subtype)
+            if subtype_dtype in ("float64",):
+                dtype = "float64"
+            else:
+                dtype = "float32"
+        elif file_.subtype not in _SUBTYPE2DTYPE:
+            raise ValueError(f"Unsupported subtype: {file_.subtype}")
+        else: