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Enable the microphone: switch to the Capture tab with F4 and enable a channel with Space. Enable the microphone: switch to the Capture tab with F4 and enable a channel with Space. Select your correct sound card using F6 and select F5 to see recording controls. Move around with left and right arrow keys. Increase and decrease volume with up and down arrow keys. Increase and decrease volume for left/right channel individually with "Q", "E", "Z", and "C" keys. Mute/Unmute with the "M" key. An "MM" means muted, and "OO" means unmuted. When you exit by pressing the ESCAPE key your changes will be saved.[[File:alsa-micboost.jpg|thumb|none|200px]][[File:alsa-micboost.jpg|thumb|none|100px]]Microphone boosting is a toggle, MM indicates off, and 00 indicates on.===Intentionally Disabling and Hiding HDMI Audio When Using an Add-on Soundboard===It can be somewhat problematic under certain circumstances to have all of those HDMI audio interfaces detected and visible to ALSA and PulseAudio. Rather than just muting or disabling them, you can blacklist the drives so the system does not load them on boot. However, under some circumstances this can also disable other sound cards depending on your configuration and chipset.On a Dell Precision system with an AMD video card (this is an example system) the four video ports create four HDMI audio devices in addition to the motherboard audio. Disabling the HDMI audio interface by blacklisting snd_hda_intel will also disable the onboard audio. However, when an addon soundcard is used, such as an installed PCI card or USB sound card, there are advantages to blacklisting snd_hda_intel so HDMI and onboard sound are neither loaded nor recognized by the system. This cleans things up and resolves issues with some games that improperly request the ALSA device including SteamOS games. For the example a PCI sound card was added to the system and onboard audio was also disabled on bios. Then do this: sudo vi /etc/modprobe.d/blacklist.confand add blacklist snd_hda_intel blacklist snd_hda_codec_hdmithen reboot.Now the only audio playback and capture devices visible to the system are those provided by the addon soundboard. This worked with an Ensoniq PCI card and was also tested with an MAudio USB soundboard.===Stop Automatic Microphone Gain===Some applications, like Google Chrome, or Discord, will automatically adjust the microphone input gain. Often, they do a poor job of it. The UI has no option to disable automatic mic gain adjustment. ''Question: Is there any way to prevent application from changing volume level of my microphone?''Yes. This solution has been tested and confirmed working on Linux Mint (Ubuntu). Edit the configuration file /usr/share/pulseaudio/alsa-mixer/paths/analog-input-internal-mic.conf sudo vi /usr/share/pulseaudio/alsa-mixer/paths/analog-input-internal-mic.confLook for this block: [Element Capture] switch = mute volume = merge override-map.1 = all override-map.2 = all-left,all-rightAnd specifically change the line volume = mute to: [Element Capture] switch = mute volume = 80 override-map.1 = all override-map.2 = all-left,all-rightIn my example I set the mic gain to 80. You can adjust that number to best suit your needs via trial and error. Once the edit is done and saved you need to issue the following command. It is best to close whatever application is using the mic first. sudo alsa force-reloadThis solution comes from the web site [https://askubuntu.com/questions/749407/is-there-any-way-to-prevent-application-from-changing-volume-level-of-my-microph AskUbuntu - Is there any way to prevent application from changing volume level of my microphone?] or see also [https://askubuntu.com/questions/279407/how-to-disable-microphone-from-auto-adjusting-its-input-volume this post].