diff --git a/libs/ardour/ardour/panner.h b/libs/ardour/ardour/panner.h
index 9d6a248de0..b07167862e 100644
--- a/libs/ardour/ardour/panner.h
+++ b/libs/ardour/ardour/panner.h
@@ -140,13 +140,23 @@ class BaseStereoPanner : public StreamPanner
 	static double azimuth_to_lr_fract (double azi) { 
 		/* 180.0 degrees=> left => 0.0 */
 		/* 0.0 degrees => right => 1.0 */
-		return 1.0 - (azi/180.0);
+
+                /* humans can only distinguish 1 degree of arc between two positions,
+                   so force azi back to an integral value before computing
+                */
+
+		return 1.0 - (rint(azi)/180.0);
 	}
 
 	static double lr_fract_to_azimuth (double fract) { 
 		/* fract = 0.0 => degrees = 180.0 => left */
 		/* fract = 1.0 => degrees = 0.0 => right */
-		return 180.0 - (fract * 180.0);
+
+                /* humans can only distinguish 1 degree of arc between two positions,
+                   so force azi back to an integral value after computing
+                */
+
+		return rint (180.0 - (fract * 180.0));
 	}
 	
 	/* old school automation loading */