diff --git a/conf/vars.xml b/conf/vars.xml
index 6fea40b88c..90724f4427 100644
--- a/conf/vars.xml
+++ b/conf/vars.xml
@@ -1,6 +1,7 @@
   <!-- Preprocessor Variables
        These are introduced when configuration strings must be consistent across modules. 
    -->
+  <X-PRE-PROCESS cmd="set" data="sound_prefix=$${base_dir}/sounds/en/us/callie"/>
   <X-PRE-PROCESS cmd="set" data="domain=$${local_ip_v4}"/>
   <X-PRE-PROCESS cmd="set" data="moh_uri=local_stream://moh"/>
   <!-- xmpp_client_profile and xmpp_server_profile