I have Dolby Virtual Surround Sound 5.1 speakers with Tuba CineBass Subwoofer on Acer laptop (mine is 5951G but there is also bunch of models with similar configuration of speakers with/without subwoofer). In Windows it works and sounds amazingly after installing both Realtek drivers and Dolby software from Acer support site. In Ubuntu only 2-channel sound is working.
How can I enable virtual 5.1 sound or at least subwoofer?
This really depends on whether or not you have true 5.1 speakers. See the "disclaimer" at the end of the post.
If you have true 5.1 speakers, here's how you can configure pulse to take full advantage of all five of your speakers and your subwoofer:
From etc/pulse/, copy daemon.conf and default.pa to your user's home folder. (If you've altered these configs previously, copy from your backup of the original files):
cp /etc/pulse/daemon.conf ~/.config/pulse/daemon.conf
cp /etc/pulse/default.pa ~/.config/pulse/default.pa
Add the following line to ~/.config/pulse/default.pa:
load-module module-combine channels=6 channel_map=front-left,front-right,rear-left,rear-right,front-center,lfe
Add (or uncomment) the following lines in ~/.config/pulse/daemon.conf:
remixing-produce-lfe = yes
remixing-consume-lfe = yes
lfe-crossover-freq = 80
Without the lfe-crossover-freq defined, it defaults to 0, which is not very helpful.
You can replace 80 with the desired crossover frequency (in Hz). Frequencies below this value will be sent to the LFE channel. Frequencies between 80Hz - 120Hz are generally recommended for the LFE crossover.
To enable the new settings, restart pulse with pulseaudio -k. Some applications could require a restart.
For 7.1 speakers and other configurations, the Arch Wiki has extensive PulseAudio documentation as well as dozens of examples.
Disclaimer: This answer only applies if you actually have 5 true speakers and one true LFE (subwoofer). If your surround sound is "virtualized" using only two speakers, this is a software feature and not a hardware feature that can just be enabled.
In the case of "virtual" surround sound; if you need to download and install software from the manufacturer to get the feature to work on Windows, you will probably need to do the same on Linux/Ubuntu. If they only produce software for Windows, that means the manufacturer does not support the product's software features on Mac or Linux.
Also note that there are many ways to connect audio equipment and they are not created equally. Getting 6 distinct channels from your PC to 6 distinct speakers requires compatible DAC, ports, and cables. For example, the 3.5mm headphone port on your laptop is simply not capable of true 5.1 output, even though it can carry encoded streams like Dolby Digital.
use alsamixer but first, install the extra driver support:
sudo apt-get install alsa-firmware-loaders alsa-tools alsa-tools-gui
At this point, you may need to reboot.
Then, execute the following commands in an open terminal:
alsamixer
Then, press F6 use the arrow key to select your sound card and then press ENTER.
Next, press F5 and scroll to the right using the arrow keys until you get to Auto-Mute. Use the up arrow key to disable automute.
Finally, scroll to the subwoofer using the left or right arrow key and control the volume using the up and down arrow keys. Also, press the M key to mute or unmute each channel.
According to the link in the other answer, you may have to edit the following file to enable 5.1 audio. Run the following command:
sudo nano /etc/pulse/daemon.conf
Then, press CTRL + W, type:
channels = 2
and then press ENTER to take you to the line you need to edit.
Now, change the 2 to 6 and remove the ; character and the following space at the beginning of the line so that the line should look like this:
default-sample-channels = 6
Finally, press CTRL + o and then press ENTER to save the file. Press CTRL + x to exit and then reboot.
It seems it's a bug somewhere in ubuntu, there is a bug for that on a lunchpad. If it affects you please click on "This bug affects me" there - https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1672822
And let's hope that it'll be fixed eventually
