How to record output to speakers?

If I'm not wrong, then I guess you are talking about recording "Stereo Mix" or loopback Output.

In layman's terms, Recording Stereo Mix means recording sound from speaker output.

Here's how to do it:

1. Install pavucontrol from Ubuntu Software Center.
2. Install audacity from Ubuntu Software Center.
3. Select pulse* as recording device in Audacity.
4. Click Record Button.
5. Open PulseAudio Volume Control (Search For PulseAudio Volume Control in Dash).
6. Select Recording Tab.
7. Now You Should see ALSA plug-in [audacity]. If you do not see ALSA plug-in [audacity], make sure you have clicked Record Button in audacity. You should be running recording in audacity while performing next step.
8. Select "Monitor from *". See screen shot.
9. Now you should be able to record the sound you hear from speaker or headphones.

Note: Tested in Ubuntu 12.10
Reference PulseAudio - Ubuntu Wiki

A very small, bare-bones software that does exactly what you need, is called (rather obviously) "Audio Recorder", installed like this:

sudo add-apt-repository ppa:audio-recorder/ppa
sudo apt-get update && sudo apt-get install audio-recorder

Files are saved automatically to the ~/Audio directory.

Command Line

1. Install sudo apt-get install pulseaudio-utils lame mpg123

2. Search for your speakers and tap into your speaker's monitor stream:

   pacmd list-sinks | grep -e 'name:' -e 'index' -e 'Speakers'

   or

   pacmd list-sources | grep -e 'name:' -e 'index' -e 'Speakers'

3. Play anything you want to record and type in parec -d alsa_output.pci-0000_00_1f.3.analog-stereo.monitor | lame -r -V0 - out.mp3

4. Hit ctrl+c to stop recording and play the recorded file mpg123 out.mp3

Minimalistic GUI

A very simple GUI to do this, pull all the files from here and run install.sh Goto Dash and search for Record Speakers