diff --git a/init.lua b/init.lua
index 6a1d989..9e6389c 100644
--- a/init.lua
+++ b/init.lua
@@ -1,12 +1,17 @@
 -- Window Block
 
+local sfx
+if minetest.registered_modpath("default") then
+	sfx = default.node_sound_glass_defaults()
+end
+
 minetest.register_node("mesecons_window:window_closed", {
 	description="Mesecon Window",
 	_doc_items_longdesc = "A Mesecon receptor which is opaque when it isn't powered and is fully transparent to light and sunlight when powered.",
 	tiles = {"mesecons_window_closed.png"},
 	is_ground_content = false,
 	groups = {cracky=3, oddly_breakable_by_hand=3},
-	sounds = default.node_sound_glass_defaults(),
+	sounds = sfx,
 	mesecons = {conductor = {
 		state = mesecon.state.off,
 		rules = { --axes
@@ -31,7 +36,7 @@ minetest.register_node("mesecons_window:window_open", {
 	paramtype = "light",
 	groups = {cracky=3, oddly_breakable_by_hand=3, not_in_creative_inventory=1},
 	drop = "mesecons_window:window_closed",
-	sounds = default.node_sound_glass_defaults(),
+	sounds = sfx,
 	mesecons = {conductor = {
 		state = mesecon.state.on,
 		rules = {
@@ -59,7 +64,7 @@ minetest.register_node("mesecons_window:filter_closed", {
 	_doc_items_longdesc = "A Mesecon receptor which is opaque when it isn't powered and is semi-transparent to light when powered.",
 	is_ground_content = false,
 	groups = {cracky=3, oddly_breakable_by_hand=3},
-	sounds = default.node_sound_glass_defaults(),
+	sounds = sfx,
 	mesecons = {conductor = {
 		state = mesecon.state.off,
 		rules = { --axes
@@ -84,7 +89,7 @@ minetest.register_node("mesecons_window:filter_open", {
 	paramtype = "light",
 	groups = {cracky=3, oddly_breakable_by_hand=3, not_in_creative_inventory=1},
 	drop = "mesecons_window:filter_closed",
-	sounds = default.node_sound_glass_defaults(),
+	sounds = sfx,
 	mesecons = {conductor = {
 		state = mesecon.state.on,
 		rules = {
@@ -113,7 +118,7 @@ minetest.register_node("mesecons_window:filter2_closed", {
 	tiles = {"mesecons_filter2_closed.png", "mesecons_filter2_closed_detail.png"},
 	is_ground_content = false,
 	groups = {cracky=3, oddly_breakable_by_hand=3},
-	sounds = default.node_sound_glass_defaults(),
+	sounds = sfx,
 	paramtype = "light",
 	sunlight_propagates = false,
 	mesecons = {conductor = {
@@ -148,7 +153,7 @@ minetest.register_node("mesecons_window:filter2_open", {
 	sunlight_propagates = true,
 	groups = {cracky=3, oddly_breakable_by_hand=3, not_in_creative_inventory=1},
 	drop = "mesecons_window:filter2_closed",
-	sounds = default.node_sound_glass_defaults(),
+	sounds = sfx,
 	mesecons = {conductor = {
 		state = mesecon.state.on,
 		rules = {