diff --git a/externals/iemlib/iem_t3_lib/src/t3_line~.c b/externals/iemlib/iem_t3_lib/src/t3_line~.c
index 21b7f856d6656d0bceeb98ab748a58d483094056..92878c63c6b79450742791cc77ca19131617db97 100644
--- a/externals/iemlib/iem_t3_lib/src/t3_line~.c
+++ b/externals/iemlib/iem_t3_lib/src/t3_line~.c
@@ -264,7 +264,7 @@ void t3_line_tilde_setup(void)
 {
   t3_line_tilde_class = class_new(gensym("t3_line~"), (t_newmethod)t3_line_tilde_new,
     (t_method)t3_line_tilde_free, sizeof(t_t3_line_tilde), 0, A_DEFFLOAT, 0);
-  class_addmethod(t3_line_tilde_class, (t_method)t3_line_tilde_dsp, gensym("dsp"), 0);
+  class_addmethod(t3_line_tilde_class, (t_method)t3_line_tilde_dsp, gensym("dsp"), A_CANT, 0);
   class_addmethod(t3_line_tilde_class, (t_method)t3_line_tilde_stop, gensym("stop"), 0);
   class_addmethod(t3_line_tilde_class, (t_method)t3_line_tilde_ft1, gensym("ft1"), A_FLOAT, 0);
   class_addlist(t3_line_tilde_class, (t_method)t3_line_tilde_list);
diff --git a/externals/iemlib/iem_t3_lib/src/t3_sig~.c b/externals/iemlib/iem_t3_lib/src/t3_sig~.c
index c2f8eea8c1d734973d3a58739afbe26913fe5f9d..fdbb5e8f60846d8c2fb149bce46081994b48d88d 100644
--- a/externals/iemlib/iem_t3_lib/src/t3_sig~.c
+++ b/externals/iemlib/iem_t3_lib/src/t3_sig~.c
@@ -185,7 +185,7 @@ void t3_sig_tilde_setup(void)
 {
   t3_sig_tilde_class = class_new(gensym("t3_sig~"), (t_newmethod)t3_sig_tilde_new,
         (t_method)t3_sig_tilde_free, sizeof(t_t3_sig_tilde), 0, A_DEFFLOAT, 0);
-  class_addmethod(t3_sig_tilde_class, (t_method)t3_sig_tilde_dsp, gensym("dsp"), 0);
+  class_addmethod(t3_sig_tilde_class, (t_method)t3_sig_tilde_dsp, gensym("dsp"), A_CANT, 0);
   class_addmethod(t3_sig_tilde_class, (t_method)t3_sig_tilde_stop, gensym("stop"), 0);
   class_addlist(t3_sig_tilde_class, (t_method)t3_sig_tilde_list);
 //  class_sethelpsymbol(t3_sig_tilde_class, gensym("iemhelp/help-t3_sig~"));