diff --git a/externals/earplug~/earplug~.c b/externals/earplug~/earplug~.c
index a0b704c3e015309556fbf721e9a9168f9e4e4a1c..4f0c6e66d1925b52f092cdb7a74e925d83175679 100644
--- a/externals/earplug~/earplug~.c
+++ b/externals/earplug~/earplug~.c
@@ -255,5 +255,5 @@ void earplug_tilde_setup(void)
    
     CLASS_MAINSIGNALIN(earplug_class, t_earplug, f);
    
-    class_addmethod(earplug_class, (t_method)earplug_dsp, gensym("dsp"), 0);
+    class_addmethod(earplug_class, (t_method)earplug_dsp, gensym("dsp"), A_CANT, 0);
 }