note mono sound requirement

webapp/views/pages/modding.ejs

@@ -337,6 +337,12 @@ use Blender 2.8 then export to any model format supported by Irrlicht
 (Usually 3ds, obj, are good static formats--Irrlicht also supports other
 common formats such as ms3d and md3; uncommon formats; and x for
 animated 3D models but x is not as efficient in size as b3d).</p>
+<h2>Sounds</h2>
+<p>Sounds must be mono if you want 3D positional audio, such as for
+mob sounds (see
+"<a href="http://irrlicht.sourceforge.net/forum/viewtopic.php?f=1&t=30371">irrKlang
+3d Sound Position</a>" on the Irrlicht forum, and "The Modding Book").
+</p>
 <h2>Creating New Ores</h2>
 Creating new ores or other blocks may be confusing after you learn the
 API. If you want about 48 blocks before you find another cluster of