Translations by Andrew Janke

I hear crackling or buzzing when sounds are playing

If you hear crackling or buzzing when sounds are playing on your computer, you may have a problem with the audio cables or connectors, or a problem with the drivers for the sound card.

Check that the speakers are plugged in correctly.

If the speakers aren't fully plugged in, or if they are plugged into the wrong socket, you might hear a buzzing sound.

Make sure the speaker/headphone cable isn't damaged.

Audio cables and connectors can gradually wear with use. Try plugging the cable or headphones into another audio device (like an MP3 player or a CD player) to check if there is still a crackling sound. If there is, you may need to replace the cable or headphones.

Check if the sound drivers aren't very good.

Some sound cards don't work very well on Linux because they don't have very good drivers. This problem is more difficult to identify. Try searching for the make and model of your sound card on the internet, plus the search term "Ubuntu", to see if other people are having the same problem.

You can run <cmd>sudo lspci -v</cmd> in the <app>Terminal</app> to get more information about your sound card.

Check that it's not muted, that cables are plugged in properly, and that the sound card is detected.

I can't hear any sounds on the computer

Make sure that the sound is not muted

Some laptops have mute switches or keys on their keyboards—try pressing that key to see if it unmutes the sound.

Check that the speakers are turned on and connected properly

If your computer has external speakers, make sure that they are turned on and that the volume is turned up. Make sure that the speaker cable is securely plugged into the "output" audio socket on the back of the computer. This socket is usually light green in color.

Some sound cards are able to switch which socket they use for output (to the speakers) and input (from a microphone, for instance). The output socket may be different when running Linux than on Windows or Mac OS. Try connecting the speaker cable to the different audio sockets on the computer in turn to see if that works.

A final thing to check is that the audio cable is securely plugged into the back of the speakers. Some speakers have more than one input too.

Check that the right sound device is selected

Some computers have multiple "sound devices" installed. Some of these are capable of outputting sound and some are not, so you should check that you have the correct one selected. This might involve some trial-and-error to choose the right one.

If that doesn't work, you might want to try doing the same for any other devices that are listed.

Check that the sound card was detected properly

Your sound card may not have been detected properly. If this has happened, your computer will think that it isn't able to play sound. A possible reason for the card not being detected properly is that the drivers for the card are not installed.

Go to the <link xref="unity-dash-intro">dash</link> and open the Terminal.

Type <cmd>aplay -l</cmd> and press <key>Enter</key>.

A list of devices will be shown. If there are no <gui>playback hardware devices</gui>, your sound card has not been detected.

If your sound card is not detected, you may need to manually install the drivers for it. How you do this will depend on the card you have.

You can see what sound card you have by using the <cmd>lspci</cmd> command in the <app>Terminal</app>. You can get more complete results if you run <cmd>lspci</cmd> as <link xref="user-admin-explain">superuser</link>; enter <cmd>sudo lspci</cmd> and type your password. See if an <em>audio controller</em> or <em>audio device</em> is listed—it should have the sound card's make and model number. <cmd>sudo lspci -v</cmd> will show a list with more detailed information.

You may be able to find and install drivers for your card by searching the Internet. Otherwise, you can <link xref="ubuntu-report-bug">file a bug</link>.

If you can't get drivers for your sound card, you might prefer to buy a new sound card. You can get sound cards that can be installed inside the computer and external USB sound cards.

Use an analog or USB microphone and select a default input device.

Use a different microphone

If you have a USB microphone, plug it into any USB port on your computer. USB microphones act as separate audio devices, and you may have to specify which microphone to use by default.

Select a default audio input device

On the <gui>Input</gui> tab, select the device in the list of devices. The input level indicator should respond when you speak.

Connect speakers or headphones and select a default audio output device.

Use different speakers or headphones

You can use external speakers or headphones with your computer. Speakers usually either connect using a circular TRS (<em>tip, ring, sleeve</em>) plug or with USB.

If your speakers or headphones have a TRS plug, plug it into the appropriate socket on your computer. Most computers have two sockets: one for microphones and one for speakers. Look for a picture of headphones next to the socket. Speakers or headphones plugged into a TRS socket will usually be used by default. If not, see the instructions below for selecting the default device.

If you have USB speakers or headphones, or analog headphones plugged into a USB sound card, plug them into any USB port. USB speakers act as separate audio devices, and you may have to specify which speakers to use by default.

On the <gui>Output</gui> tab, select the device in the list of devices.

If you don't see your device on the <gui>Output</gui> tab, check the <gui>Hardware</gui> tab. Select your device and try different profiles.

Set the sound volume for the computer and control the loudness of each application.

Change the sound volume

Of course, if you have external speakers, you can also change the volume using the volume control on the speakers themselves. Some headphones have a volume control too.

Changing the sound volume for individual applications

Only applications that are playing sounds will be listed. If an application is playing sounds but isn't listed, it might not support the feature that lets you control its volume in this way. In that case, you can't change its volume.

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