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:
then to unload it use this with your module number:
pactl unload-module 27
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:
Now the modules will load automatically and your line-in audio will always be available.