为PulseAudio设置默认配置文件

1. Overview

PulseAudio is a sound server in Linux that’s used to manage audio input and output for multiple applications. We can improve its performance and compatibility by configuring it to use a default profile for audio devices. This configuration enhances our audio experience, especially if we have multiple audio devices.

In this tutorial, we’ll discuss various ways to set a default profile for PulseAudio. We’ll use the pactl command in terminal and modify the PulseAudio configuration file. To demonstrate, we’ll focus on the GNOME desktop environment.

2. Understanding Pulseaudio Profiles

PulseAudio profiles are used to manage audio devices on our system. Each profile determines how PulseAudio interacts with the hardware, including the input and output channels, sample rates, and audio formats. Some common profiles include analog stereo output + analog stereo input, analog stereo duplex, and digital stereo output.

So, let’s start by checking all available profiles for our audio devices using the pacmd command:

$ pacmd list-cards
1 card(s) available.
    index: 0
    name: <alsa_card.pci-0000_00_1b.0>
        driver: <module-alsa-card.c>
        owner module: 7
    ...
    properties:
        ...
    profiles:
        input:analog-stereo: Analog Stereo Input (priority 32833, available: unknown)
        output:analog-stereo: Analog Stereo Output (priority 39268, available: unknown)
        output:analog-stereo+input:analog-stereo: Analog Stereo Duplex (priority 39333, available: unknown)
        ...

Above, we display detailed information about all available audio cards, including their profiles. From our output, we have an audio card with an index of 0 named alsa_card.pci-0000_00_1b.0.

At this point, we’ll identify the desired profile to set as default. In particular, let’s set output:analog-stereo+input:analog-stereo as the default profile.

2.1. Using the pactl Command

 pactl is a command line tool used to control the PulseAudio server. Here, we’ll use it to set a default profile for PulseAudio.

To begin, let’s check the syntax we’ll use:

$ pactl set-card-profile <card_name_or_index> <profile_name>

Let’s examine this syntax:

• set-card-profile – represents a sub-command of pactl that instructs PulseAudio we want to change the profile of a specific audio card
• <card_name_or_index> – specifies the name or the index number of the audio card we want to configure
• <profile_name> – specifies the profile we want to set for the specified audio card

Next, let’s set output:analog-stereo+input:analog-stereo as the default profile for the alsa_card.pci-0000_00_1b.0. audio card*:*

$ pactl set-card-profile alsa_card.pci-0000_00_1b.0 output:analog-stereo+input:analog-stereo

If no error occurs, we’ve successfully set the default profile.

2.2. Modifying the PulseAudio Configuration File

On the other hand, we can directly modify the PulseAudio configuration file. Furthermore, using this file allows us to customize various settings and behaviors of the PulseAudio server. It’s usually located at /etc/pulse/default.pa.

Firstly, let’s open the configuration file:

$ sudo nano /etc/pulse/default.pa

Here, we use sudo to open the /etc/pulse/default.pa file with superuser privileges in the nano text editor.

While in the configuration file, we’ll look for a section that loads module-udev-detect. To clarify, this module is used to detect and configure audio devices:

...
.ifexists module-udev-detect.so
load-module module-udev-detect tsched=0
...

Within this section, we’ll find a line load-module module-udev-detect tsched=0 and below it add a line specifying the default profile for our audio device:

...
load-module module-udev-detect tsched=0
set-card-profile alsa_card.pci-0000_00_1b.0 output:analog-stereo+input:analog-stereo
...

Above, we set the profile of the alsa_card.pci-0000_00_1b.0 audio card to use analog stereo for both input and output. This configuration is suitable for playing and recording audio using standard stereo channels. Now, let’s save the file and exit the text editor.

Finally, to apply the changes, we need to restart the PulseAudio service:

$ pulseaudio -k

The above command restarts the PulseAudio service. This reloads the configuration file and applies the changes.

3. Conclusion

In this article, we discussed setting a default profile for PulseAudio. Firstly, we identified all the available profiles on our system. Then, we set a default profile for PulseAudio using pactl in the command line.

Also, we learned to set the default profile by directly modifying the PulseAudio configuration file. So, pactl is useful for quick and temporary changes. However, modifying the PulseAudio configuration file makes a more permanent change that applies every time PulseAudio starts up.