• Installing alsa-lib:

   ```bash
   sudo apt-get install libasound2-dev
   ```

• Using alsa-lib in a C program to play audio:

   ```c
   #include 

 int main() {
     snd_pcm_t *handle;
     snd_pcm_hw_params_t *params;
     unsigned int sample_rate = 44100;
     int dir;
     
     // Open PCM device for playback
     snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
     
     // Allocate hardware parameters object
     snd_pcm_hw_params_malloc(¶ms);
     
     // Initialize parameters
     snd_pcm_hw_params_any(handle, params);
     
     // Set parameters
     snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
     snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
     snd_pcm_hw_params_set_rate_near(handle, params, &sample_rate, &dir);
     snd_pcm_hw_params_set_channels(handle, params, 2);
     
     // Write parameters to the driver
     snd_pcm_hw_params(handle, params);
     
     // Free the hardware parameters object
     snd_pcm_hw_params_free(params);
     
     // Prepare the PCM device
     snd_pcm_prepare(handle);
     
     // Clean up and close the PCM device
     snd_pcm_close(handle);
     
     return 0;
 }
 ```

• Listing available PCM devices:

   ```bash
   aplay -l
   ```

• Adjusting mixer settings with alsamixer:

   ```bash
   alsamixer
   ```

• alsa-lib: A library for the Advanced Linux Sound Architecture (ALSA), providing an API for interacting with audio hardware on Linux. It supports high-quality audio playback and recording, and includes interfaces for PCM, mixing, MIDI, and control. It is widely used in developing audio applications and systems on Linux.