diff --git a/ivas_processing_scripts/audiotools/convert/__init__.py b/ivas_processing_scripts/audiotools/convert/__init__.py
index 9698dd4f56b0b8686485ef739296f0f7d6a3c3f3..8ca2d2f7669cbe332d44132ef25c426f6d9c7ac5 100755
--- a/ivas_processing_scripts/audiotools/convert/__init__.py
+++ b/ivas_processing_scripts/audiotools/convert/__init__.py
@@ -214,6 +214,8 @@ def process_audio(
 
     """delay audio"""
     if delay is not None:
+        if isinstance(x, audio.ObjectBasedAudio):
+            raise ValueError("Delay not possible for ISM input")
         if logger:
             logger.debug(f"Delaying audio by {delay} ms")
         x.audio = audioarray.delay(x.audio, x.fs, delay)