Comment 49 for bug 1451170

https://www.asus.com/Notebooks/N550LF/

what is quad speaker array ?

do all speakers of your laptop work as expected ?

only pulseaudio 7.0 provide LFE filtering

https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/1500498

but only ppa and not offically supported in 15.10