freeswitch/conf/rayo/autoload_configs/shout.conf.xml

<configuration name="shout.conf" description="mod shout config">
  <settings>
    <!-- Don't change these unless you are insane -->
    <!--<param name="decoder" value="i586"/>-->
    <!--<param name="volume" value=".1"/>-->
    <!-- mod_shout sets output amplitude scale to 8192 by default - preserve mpg123 default of 32768 -->
    <param name="outscale" value="32768"/>
  </settings>
</configuration>