diff --git a/libs/ardour/audiosource.cc b/libs/ardour/audiosource.cc
index 431aa84b07..004807ac85 100644
--- a/libs/ardour/audiosource.cc
+++ b/libs/ardour/audiosource.cc
@@ -663,7 +663,9 @@ AudioSource::read_peaks_with_fpp (PeakData *peaks, samplecnt_t npeaks, samplepos
 			}
 
 			if (zero_fill) {
-				cerr << "Zero fill end of peaks (@ " << read_npeaks << " with " << zero_fill << ")" << endl;
+#ifndef NDEBUG
+				cerr << "Zero fill '" << _name << "' end of peaks (@ " << read_npeaks << " with " << zero_fill << ")" << endl;
+#endif
 				memset (&peak_cache[read_npeaks], 0, sizeof (PeakData) * zero_fill);
 			}