If you have multiple sound cards, see the MultipleCards and. If the directory does not exist, or it is empty, use the ALSA snddevices script or similar to create it and the device special files in it.
Run alsamixer both as root and as a non- root ordinary user. If the latter fails, the permissions on the device special files don't allow access by ordinary users. There are several options to fix this, depending on security requirements, your distribution and how your PC is set up:.
Note that ALSA sort of misnames the channels of the mixers of many cards. Use alsamixer to play around with the settings of the most obvious sounding channels. ALSA modules and Sound cards may describe what the channels for a specific sound card. Usually, make sure that the at least the Master and PCM and Wave or Headphone if present channels are unmuted and have non zero volume.
For laptop users, try toggling the External Amplifier switch. If you hear no sound, it may be because the card is in analog mode and you have digital speakers or viceversa.
If you still hear no sound, your application may be set up to use OSS. Check with your application's preferences to see if this is the case. Also check whether other applications are blocking ALSA, by running whilst ideally playing sound in them :. If your application does not support ALSA, there are three possible solutions:.
You can also set the default for applications that use libao for example mpg and mpg by putting the line. OssEmulation provides details on OSS emulation. This is usually however a very bad thing to do, and you should try instead to fix your library building process. As root, type "lsmod".
Look at the "Used by" column. If it has all "-", this is bad. It should look more like the second output. This is not an ALSA problem. Unluckily, I don't know how to fix this problem yet. One possible fix: Check to make sure that the kernel that is currently running is the one against which the modules were compiled.
You may have compiled a new kernel and not installed it, or made a mistake in your bootloader configuration. Should get you some errors such as. Problem: kernel Solution: As I was just upgrading the linux kernel from 2. Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up. Connect and share knowledge within a single location that is structured and easy to search. When it opens, run the command s below:. Ubuntu Community Ask!
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Learn more. Ask Question. Asked 7 years, 10 months ago. If you have at least the devices controlC0 and pcmC0D0p or similar, then your sound modules have been detected and loaded properly.
If this is not the case, your sound modules have not been detected properly. To solve this, you can try loading the modules manually:. Depending on what shell you use, add the following line to your shell's configuration file:. Install the alsaequal AUR package. Also install libalsaequal AUR for bit application support. Install the alsaequal-mgr AUR package.
When you are satisfied with the state, you may give it a name "foo" in this example and save it:. You then have to update the equalizer by alsamixer -D equal. You can thus create different equalizer states for games, movies, music genres, VoIP apps, etc. See the project page and the help message for more options. Install the alsa-plugins , ladspa and swh-plugins packages if you do not already have them.
When software mixing is enabled, ALSA is forced to resample everything to the same frequency 48 kHz by default when supported. By default, it will try to use the speexrate converter to do so, and fallback to low-quality linear interpolation if it is not available [6]. Thus, if you are getting poor sound quality due to bad resampling, the problem can be solved by simply installing the alsa-plugins package.
Both perform well enough that in practice it does not matter which one you choose, so using the best converter is usually not worth the extra CPU cycles it requires. In order for stereo sources like music to be able to saturate a 5. In darker days this used to be tricky and error prone but nowadays plugins exist to easily take care of this task.
We will use the upmix plugin, included in the alsa-plugins package. The following example adds a new PCM channel that you can use for upmixing. If you want all sound sources to go through this channel, add it as a default below the previous definition like so:. The plugin automatically allows multiple sources to play through it without problems so setting is as a default is actually a safe choice.
If this is not working, you have to setup your own dmixer for the upmixing PCM like this:. If you want to downmix sources to stereo because you, for instance, want to watch a movie with 5.
Mixing enables multiple applications to output sound at the same time. Most discrete sound cards support hardware mixing, which is enabled by default if available. Integrated motherboard sound cards such as Intel HD Audio , usually do not support hardware mixing.
On such cards, software mixing is done by an ALSA plugin called dmix. This feature is enabled automatically if hardware mixing is unavailable.
Auto-Mute Mode can be configured on startup with amixer. For example, to disable it:. Alternatively, the graphical interface can be utilized through alsamixer. In order to save any modifications, use:. You might want to play music via external speakers connected via mini jack and internal speakers simultaneously. This can be done by unmuting Auto-Mute item using alsamixer or amixer :. You might want a jack alternative to create a virtual recording or play device in order to mix different sources, using the snd-aloop module:.
Another thing you could do with this approach, is using festival to generate a voice into a recording stream using an script like this:. The alsa-utils package also contains the alsa-info. See ALSA bug tracking for more info.
The ALSA driver can fully reconfigure attached codecs the parts of the sound system that actually process audio streams , by doing:. On some modern laptops you may have a combined 3. To make ALSA correctly detect plug-in status on your 3. Note: Adding users to the audio group allows direct access to devices. Keep in mind, that this allows applications to exclusively reserve output devices. This may break software mixing or fast-user-switching on multi-seat systems.
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