I don't know about anyone else, but the default sound limitations are a tad too conservative for my laptop. The sound is so faint at times I can hardly hear it on my Razer Blade 2015. So if you want to boost the sound you can enable it past 100%, but be warned you also run the risk of harming your speakers if you aren't careful.
So if you wish to proceed simply install Kmix if you are using Kubuntu and then enable "Overdrive", you can do that by clicking on the system tray icon for sound, which you might have two now since Kmix isn't normally installed any more and then clicking on the config button in the bottom right hand corner. Then click on the General icon in the window that pops open. You should then see a checkbox that is the "Enable Overdrive"
After this point you have to restart kmix/pulseaudio. You can easily do that by simply restarting, or if you know how just restart it manually.
sudo apt install kmix
If you need more pictures - click here
UPDATE : A patch is on the way for the new sound widget so this won't be required. For more information visit - click here