diff --git a/libs/audiographer/src/general/analyser.cc b/libs/audiographer/src/general/analyser.cc
index 459cd6a506..1ef55ed87b 100644
--- a/libs/audiographer/src/general/analyser.cc
+++ b/libs/audiographer/src/general/analyser.cc
@@ -35,6 +35,7 @@ Analyser::Analyser (float sample_rate, unsigned int channels, framecnt_t bufsize
 	//printf ("NEW ANALYSER %p r:%.1f c:%d f:%ld l%ld\n", this, sample_rate, channels, bufsize, n_samples);
 	assert (bufsize % channels == 0);
 	assert (bufsize > 1);
+	assert (_bufsize > 0);
 	if (channels > 0 && channels <= 2) {
 		using namespace Vamp::HostExt;
 		PluginLoader* loader (PluginLoader::getInstance ());