diff --git a/src/lerobot/datasets/lerobot_dataset.py b/src/lerobot/datasets/lerobot_dataset.py
index f9ffd6694..05e6ec5cf 100644
--- a/src/lerobot/datasets/lerobot_dataset.py
+++ b/src/lerobot/datasets/lerobot_dataset.py
@@ -776,7 +776,7 @@ class LeRobotDataset(torch.utils.data.Dataset):
         self.revision = revision if revision else CODEBASE_VERSION
         self.video_backend = video_backend if video_backend else get_safe_default_codec()
         self.audio_backend = (
-            audio_backend if audio_backend else "trochaudio"
+            audio_backend if audio_backend else "torchaudio"
         )  # Waiting for torchcodec release #TODO(CarolinePascal)
         self.delta_indices = None
         self.batch_encoding_size = batch_encoding_size
@@ -1950,7 +1950,7 @@ class LeRobotDataset(torch.utils.data.Dataset):
         obj._recorded_frames = 0
         obj._writer_closed_for_reading = False
         obj.audio_backend = (
-            audio_backend if audio_backend is not None else "trochaudio"
+            audio_backend if audio_backend is not None else "torchaudio"
         )  # Waiting for torchcodec release #TODO(CarolinePascal)
         return obj
 
diff --git a/src/lerobot/microphones/utils.py b/src/lerobot/microphones/utils.py
index 675c51e1f..7356bbb46 100644
--- a/src/lerobot/microphones/utils.py
+++ b/src/lerobot/microphones/utils.py
@@ -35,7 +35,7 @@ def make_microphones_from_configs(microphone_configs: dict[str, MicrophoneConfig
 
 def async_microphones_start_recording(
     microphones: dict[str, Microphone],
-    output_files: list[str | None] | None,
+    output_files: list[str | None] | None = None,
     multiprocessing: bool = False,
     overwrite: bool = True,
 ):