diff --git a/modules/juce_audio_plugin_client/AAX/juce_AAX_Wrapper.cpp b/modules/juce_audio_plugin_client/AAX/juce_AAX_Wrapper.cpp
index 15debaaca2..b4a3ea7dad 100644
--- a/modules/juce_audio_plugin_client/AAX/juce_AAX_Wrapper.cpp
+++ b/modules/juce_audio_plugin_client/AAX/juce_AAX_Wrapper.cpp
@@ -624,8 +624,12 @@ struct AAXClasses
         AAX_Result GetParameterDefaultNormalizedValue (AAX_CParamID paramID, double* result) const override
         {
             if (! isBypassParam (paramID))
+            {
                 *result = (double) pluginInstance->getParameterDefaultValue (getParamIndexFromID (paramID));
 
+                jassert (*result >= 0 && *result <= 1.0f);
+            }
+
             return AAX_SUCCESS;
         }
 
diff --git a/modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm b/modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm
index ad40e26aae..69b16a6028 100644
--- a/modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm
+++ b/modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm
@@ -482,6 +482,8 @@ public:
             outParameterInfo.minValue = 0.0f;
             outParameterInfo.maxValue = 1.0f;
             outParameterInfo.defaultValue = juceFilter->getParameterDefaultValue (index);
+            jassert (outParameterInfo.defaultValue >= outParameterInfo.minValue
+                      && outParameterInfo.defaultValue <= outParameterInfo.maxValue);
             outParameterInfo.unit = kAudioUnitParameterUnit_Generic;
 
             return noErr;
diff --git a/modules/juce_audio_plugin_client/VST3/juce_VST3_Wrapper.cpp b/modules/juce_audio_plugin_client/VST3/juce_VST3_Wrapper.cpp
index 312dccc633..03aaa87a70 100644
--- a/modules/juce_audio_plugin_client/VST3/juce_VST3_Wrapper.cpp
+++ b/modules/juce_audio_plugin_client/VST3/juce_VST3_Wrapper.cpp
@@ -174,6 +174,7 @@ public:
             const int numSteps = p.getParameterNumSteps (index);
             info.stepCount = (Steinberg::int32) (numSteps > 0 && numSteps < 0x7fffffff ? numSteps - 1 : 0);
             info.defaultNormalizedValue = p.getParameterDefaultValue (index);
+            jassert (info.defaultNormalizedValue >= 0 && info.defaultNormalizedValue <= 1.0f);
             info.unitId = Vst::kRootUnitId;
             info.flags = p.isParameterAutomatable (index) ? Vst::ParameterInfo::kCanAutomate : 0;
         }