Ubuntu – Set a max volume for the Terminal bell

Parts of this answer comes from Setting microphone input volume using the command line?, placed here for your convenience.

Increase volume by 5%

amixer -D pulse sset Master 5%+

Decrease volume by 5%

amixer -D pulse sset Master 5%-

Set volume to 50%

amixer -D pulse sset Master 50%

If you are using ALSA, amixer can be helpful for your script programming.

When dropping the amixer --help command in a terminal you will see something like this:

Depending on your soundcard, levels may be different than mine, but you can use alsamixer in the terminal in order to check which levels and which features in your sound card you can call in a command to set the volume as you wish.

In my example, with my principal sound card (I have 2: the embedded and a PCI audio card), levels are from 0 to 100, this way I can change the volume of a desired input/output in my soundcard by dropping in a terminal the next command:

amixer -c 0 set Front 50DB 
amixer -c 0 set Front 64DB 

In the first command, the result will set the Front panel output to 78% level and the second one will set the Front panel output to 100% level.

In order to gather information related to your mixer controls, drop the amixer command with no parameters and you will get a list. Or indicate which audio device you wish to see a list of controls with amixer -c X (where "X" is the number of your audio device).

BTW: Remember that DB values are calculated logarithmically and not linearly.

Remember that this command allow you to control parameters on whatever sound device you are currently using.

Good luck!

With PulseAudio 8.0 on Ubuntu 16.04 and a single sound card, you can set the default master volume to 50% with the following file. By including the system default you don't have to worry about changes in the distribution's defaults.

$ cat ~/.config/pulse/default.pa
.include /etc/pulse/default.pa

# Set volume to 50% on boot
set-sink-volume 0 32768

If you have multiple cards, replace the index number with the name since order is not guaranteed. In addition, if you want to adjust the volume determine the "base volume" which represents the max and calculate the equivalent percentage.

$ pacmd list-sinks | grep -e "name:" -e "index:" -e "base volume:"
  * index: 0
    name: <alsa_output.card0>
    base volume: 65536 / 100% / 0.00 dB
  * index: 1
    name: <alsa_output.card1>
    base volume: 32768 / 100% / 0.00 dB

For example, to specify the default volume of 70% for card1 the line would become:

set-sink-volume alsa_output.card1 22937