diff --git a/src/sfizz/Synth.cpp b/src/sfizz/Synth.cpp
index c980e5a0..b32b0132 100644
--- a/src/sfizz/Synth.cpp
+++ b/src/sfizz/Synth.cpp
@@ -724,12 +724,10 @@ void sfz::Synth::renderBlock(AudioSpan<float> buffer) noexcept
         }
     }
 
-#if 0
     ASSERT(!hasNanInf(buffer.getConstSpan(0)));
     ASSERT(!hasNanInf(buffer.getConstSpan(1)));
-    ASSERT(isValidAudio(buffer.getConstSpan(0)));
-    ASSERT(isValidAudio(buffer.getConstSpan(1)));
-#endif
+    CHECK(isValidAudio(buffer.getConstSpan(0)));
+    CHECK(isValidAudio(buffer.getConstSpan(1)));
 }
 
 void sfz::Synth::noteOn(int delay, int noteNumber, uint8_t velocity) noexcept
diff --git a/src/sfizz/Voice.cpp b/src/sfizz/Voice.cpp
index edb00a07..d6da13ab 100644
--- a/src/sfizz/Voice.cpp
+++ b/src/sfizz/Voice.cpp
@@ -250,8 +250,8 @@ void sfz::Voice::renderBlock(AudioSpan<float> buffer) noexcept
 #if 0
     ASSERT(!hasNanInf(buffer.getConstSpan(0)));
     ASSERT(!hasNanInf(buffer.getConstSpan(1)));
-    ASSERT(isValidAudio(buffer.getConstSpan(0)));
-    ASSERT(isValidAudio(buffer.getConstSpan(1)));
+    CHECK(isValidAudio(buffer.getConstSpan(0)));
+    CHECK(isValidAudio(buffer.getConstSpan(1)));
 #endif
 }
 
@@ -529,8 +529,8 @@ void sfz::Voice::fillWithData(AudioSpan<float> buffer) noexcept
 #if 0
     ASSERT(!hasNanInf(buffer.getConstSpan(0)));
     ASSERT(!hasNanInf(buffer.getConstSpan(1)));
-    ASSERT(isValidAudio(buffer.getConstSpan(0)));
-    ASSERT(isValidAudio(buffer.getConstSpan(1)));
+    CHECK(isValidAudio(buffer.getConstSpan(0)));
+    CHECK(isValidAudio(buffer.getConstSpan(1)));
 #endif
 }
 
@@ -595,8 +595,8 @@ void sfz::Voice::fillWithGenerator(AudioSpan<float> buffer) noexcept
 #if 0
     ASSERT(!hasNanInf(buffer.getConstSpan(0)));
     ASSERT(!hasNanInf(buffer.getConstSpan(1)));
-    ASSERT(isValidAudio(buffer.getConstSpan(0)));
-    ASSERT(isValidAudio(buffer.getConstSpan(1)));
+    CHECK(isValidAudio(buffer.getConstSpan(0)));
+    CHECK(isValidAudio(buffer.getConstSpan(1)));
 #endif
 }