diff --git a/Zframework/sfx.lua b/Zframework/sfx.lua
index a1f90819..8f5c5c20 100644
--- a/Zframework/sfx.lua
+++ b/Zframework/sfx.lua
@@ -1,5 +1,6 @@
 local type,rem=type,table.remove
 local int,rnd=math.floor,math.random
+local interval=MATH.interval
 
 local sfxList={}
 local packSetting={}
@@ -140,7 +141,7 @@ local function _play(name,vol,pos,pitch)
     S=S[n]--AU_SRC
     if S:getChannelCount()==1 then
         if pos then
-            pos=pos*stereo
+            pos=interval(pos,-1,1)*stereo
             S:setPosition(pos,1-pos^2,0)
         else
             S:setPosition(0,0,0)