Was trying to record my kid's voice using a cheap microphone in KDE.
Tried all the possible setting of Kmix but the recording is very very soft.

Anyone have ever tried and know how to do this simple thing?

While I don't know of any native application to record sound, there is Audacity. I've used it multiple times...mostly to edit songs down to a 40 second clip for a ring tone, but also to record myself playing sax. It's an excellent tool!

have a look at this.

http://linuxreviews.org/man/arecord/

I assume normal playback is working correctly?

Check you have the mic plugged into the mic socket on your sound card and not the line in. The line in socket can result in very quiet input.

Also, verify that the input is not being taken from a different mic - you might have a built-in mic in your computer and think you are talking into the external one you have plugged in, but find the actual recording is coming from the internal one. The distance from the active mic could account for strangely quiet recordings, especially if you hear a lot of fan/hard disk noise, and/or keyboard noise when you type.

You said you tried all possible mixer settings. I'd like to verify that you tried all these. The mixer checklist is:

1. Input tab / Mic level slider = near the top;
2. red indicator under Mic slider is selected (bright red)
3. The green indicator above the Mic slider is used to send mic input out through the speakers. This is useful sometimes, but beware of feedback. It's probably better to leave this off unless you use headphones to listen to the audio output.
4. Input tab / Capture red indicator is selected
5. Switches tab / Mic Boost is selected (yellow indicator)
6. Switches tab / Mic select is on the right input (just try each one)

If all this is set and it is still not working, please post the output of the amixer command in [code] tags here. amixer is in the alsa-utils package in Ubuntu... not sure about other distros.

[edit]P.S. what distro are you using?[/edit]

Noted. Went ahead and tried the physical setup in windows and recorded okay. Booted back into Debian (and openSUSE) and the recording is super soft :-(

All the tabs are moved to the maximum but still the same thing.

amixer output as follow
Any idea what's wrong with the settings?

Mic Boost is not to be moved to maximum it is an on/off switch and it was the problem with me
you will find it in the switches tab in kmix (if you are using KDE)

Not all audio devices will have a mic boost btw, so if you can't find it, it might not be relevant for the device you have.

Oops, forgot to mention that Kmix doesn't show any Mic Boost option

I do notice in the amixer output two mix levels - "Front Mic" and "Mic". Are there two Mic sockets, or a built-in mic (if you are using a laptops this might be the case).

It could be that Windows is automatically selecting the external mic when present, but ALSA is still using the internal mic. Find it and test it by rubbing you fingers over it as you record to see if you get loud sound from that mic.

Using a desktop with 2 microphone input, one at the front and another at the back of the CPU. Both tested and not much luck

I'm stumped.

That's okay , thanks for trying anyway :-)

Oh hang on - the volume for capture says 0% in your amixer output...?

But all sliders are at maximum. Any idea what can be done ?

Try using alsamixer in a terminal. This is a text-mode mixer, so it's not as nice to use but it might show some extra controls which don't show in kmix. This is pure speculation on my part - I have never seen kmix omit anything, but it's worth having a look at.

Left/right cursor keys to choose which control to select, up/down to change the levels. All the controls probably don't fit on one screen, and you can continue to press the right cursor to scroll to more controls.

The space key selects channels from alternatives, e.g. using mic instead of line in (a red L R CAPTUR indicator shows at the bottom of a control when this is done). You can toggle mute with the m key. This appears as MM at the bottom of a volume control when muted, OO otherwise. The escape key exits.

Importantly, you select groups of controls with the tab key. The selected group can be seen next to "View:" at the top left. Check all groups.