I had exactly the same problem you have, not able to get the full sound out of Beats Audio Speakers in my HP laptop. I referred several websites but this and this websites together solved the problem. Here’s what I did:
Step 1: Open a terminal (Ctrl + Alt + t) and run:
sudo apt-get instal alsa-tools-gui
Step 2: Open hda-jack-retask
1. Select the codec IDT 92HD91BXX
2. Choose Show unconnected pins
3. Remap 0x0d (Internal Speaker, Front side) to “Internal Speaker” (in my case, it was the default value, so I left it as it is)
4. Remap 0x0f to “Internal Speaker”
5. Remap 0x10 to “Internal Speaker (LFE)”
6. Apply now, then test your laptop audio now by playing some audios from youtube.
7. If it works, select “Install boot override” to save the settings to apply at boot time.