so.... Let's see if we can get a nice recording dialog going to easily test our input actually does something.
A visual readout would be nice so we shall check it with the
arecord -vv -fcd /somewhere/safe/and/useful/blah.wav (optionally set the duration with
-d in integers as seconds like:
-d 30)
The ##############+'s at the bottom (in the image callout) will dynamically go up and down according to the input level.
What if it doesn't go up and down?
Assuming you didn't edit any files on the device to do with alsa config, since the alsa config is pre-setup on these devices for you, the microphone is broken. Highly unlikely to happen IMHO though.
Also note that devices have differing sound support, if yours has none for example this will not work