roslaunch not launching nodes properly

edit

I'm getting problem while launching the audio play nodes from launch file. When i run the audio play node from terminal it works for first time, i.e if i stop this node and than again run it from terminal the audio is not comming in earphone.

when i launch the audio play from the launch file the sound dont' comes at all. When i check if the audio data is comming or not by using rostopic echo "/audio/audio" audio data are being published. Here the the audio play launch file which i run in master odroid c2.

<launch>
    <node pkg="rosserial_arduino" type="serial_node.py" name="publisher">
        <param name="port" value="/dev/ttyACM0" />
    </node>
    <include file="$(find audio_play)/launch/play.launch">
        <arg name="do_timestamp" value="false" />
        <arg name="ns" value="cap1" />
    </include>
</launch>

audio capture launch file:

<launch>
    <include file="$(find audio_capture)/launch/capture.launch">
        <arg name="device" value="hw:1,0"/>
        <arg name="ns" value="cap1" />
    </include>
    <node pkg="rosserial_arduino" type="serial_node.py" name="subscriber"/>
</launch>

I'm running two odrid c2 for this purpose to make a robot for my small project. Here one is master running play( controller ) and another is slave ( robot ). i'm using tp link wifi dongle in robot which connected to router connected to controller. i also don't know how to debug this issue since their is no presenece of erros or warnings. + the nodes and running properly.