The code related to t.audio.mixwithsystem=true is run before the audio module is loaded. Fixes issue #1430.

src/scripts/boot.lua

@@ -468,6 +468,10 @@ function love.init()
 		love._setGammaCorrect(c.gammacorrect)
 	end
 
+	if love._setAudioMixWithSystem and c.audio then
+		love._setAudioMixWithSystem(c.audio.mixwithsystem)
+	end
+
 	-- Gets desired modules.
 	for k,v in ipairs{
 		"data",
@@ -545,10 +549,6 @@ function love.init()
 		end
 	end
 
-	if love.audio then
-		love.audio.setMixWithSystem(c.audio.mixwithsystem)
-	end
-
 	-- Our first timestep, because window creation can take some time
 	if love.timer then
 		love.timer.step()