diff --git a/modules/juce_audio_processors/format_types/juce_AU_Shared.h b/modules/juce_audio_processors/format_types/juce_AU_Shared.h
index 036c44b99b..25073c9a82 100644
--- a/modules/juce_audio_processors/format_types/juce_AU_Shared.h
+++ b/modules/juce_audio_processors/format_types/juce_AU_Shared.h
@@ -373,7 +373,10 @@ struct AudioUnitHelpers
         }
 
         auto layout = processor.getBusesLayout();
-        auto maxNumChanToCheckFor = 9;
+
+        // The 'standard' layout with the most channels defined is AudioChannelSet::create9point1point6().
+        // This value should be updated if larger standard channel layouts are added in the future.
+        constexpr auto maxNumChanToCheckFor = 16;
 
         auto defaultInputs  = processor.getChannelCountOfBus (true,  0);
         auto defaultOutputs = processor.getChannelCountOfBus (false, 0);