diff --git a/ivas_processing_scripts/audiotools/metadata.py b/ivas_processing_scripts/audiotools/metadata.py
index 6c6466ece19e4adb3f8d1f886c5fbe5e3696e808..436dc6336957b5f086a2d9d7c7a5e0420d4cb77a 100755
--- a/ivas_processing_scripts/audiotools/metadata.py
+++ b/ivas_processing_scripts/audiotools/metadata.py
@@ -490,10 +490,10 @@ def check_ISM_metadata(
                 except KeyError:
                     current_item = in_meta[f"item{item_idx + 1}"]
 
-                if len(current_item) == 1:
+                if not isinstance(current_item, list):
                     # automatic search in folder
                     list_item = metadata_search(
-                        current_item[0], [item_names[item_idx]], num_objects
+                        current_item, [item_names[item_idx]], num_objects
                     )
 
                 elif len(current_item) == num_objects:
diff --git a/ivas_processing_scripts/processing/preprocessing_2.py b/ivas_processing_scripts/processing/preprocessing_2.py
index 828218f0ffe0bbe2cef7c98d11961a87d1436943..0e84c44780d3ca775cfde3b448a284de9c42b071 100644
--- a/ivas_processing_scripts/processing/preprocessing_2.py
+++ b/ivas_processing_scripts/processing/preprocessing_2.py
@@ -66,23 +66,29 @@ class Preprocessing2(Processing):
         )
 
         # add preamble
-        if self.preamble:
-            logger.debug(f"Add preamble of length {self.preamble}ms")
-            # also apply preamble to ISM metadata
-            if self.in_fmt.startswith("ISM"):
-                # read out old
-                metadata = []
-                for meta in in_meta:
-                    metadata.append(np.genfromtxt(meta, delimiter=","))
 
-                # modify metadata
-                metadata = add_remove_preamble(metadata, self.preamble)
-                meta_files = write_ISM_metadata_in_file(metadata, [out_file], True)
+        # also apply preamble to ISM metadata
+        if self.in_fmt.startswith("ISM"):
+            if not self.preamble:
+                preamble = 0
+            else:
+                preamble = self.preamble
+
+            # read out old
+            metadata = []
+            for meta in in_meta:
+                metadata.append(np.genfromtxt(meta, delimiter=","))
 
-                # modify audio object
-                audio_object.metadata_files = meta_files
-                audio_object.obect_pos = metadata
+            # modify metadata
+            metadata = add_remove_preamble(metadata, preamble)
+            meta_files = write_ISM_metadata_in_file(metadata, [out_file], True)
 
+            # modify audio object
+            audio_object.metadata_files = meta_files
+            audio_object.obect_pos = metadata
+
+        if self.preamble:
+            logger.debug(f"Add preamble of length {self.preamble}ms")
             # add preamble to actual signal
             audio_object.audio = trim(
                 audio_object.audio,