Listen to microphone over the speakers using pulseaudio

By default, We cannot hear any sound of microphone over speaker on Debian or Ubuntu OS. So, we cannot sing karaoke. After “google” its, I’ve found a solution at “http://ubuntuforums.org/showthread.php?p=8672035”.
Using this command to route the mic input through output:
pactl load-module module-loopback latency_msec=1

To turn it off:

first find the module number
it gives it to you when you run the first command, or use this to find it:
pacmd list-modules
then to unload it use this with your module number:
pactl unload-module 27

Additional:

To fix the problem permanently, you need to load the modules when Pulseaudio starts. To do this, you need to add a line to the /etc/pulse/default.pa file with the following commands:

sudo gedit /etc/pulse/default.pa

Scroll down to the bottom of the file and add this line:

load-module module-loopback

Now the modules will load automatically and your line-in audio will always be available.