I have tried that and multiple others. Some work well, some dont.
None have given me what I am looking for which it the ability to boost things like system volume, notification volume, etc. Still looking for a way to do that.
The best that I can accomplish is boosting media volume via a music or video player. If that is all you are looking for then the equalizer and bass booster will work fine.
This one works for me, and YES, do heed their cautionary message about setting things too loud.
Anybody tried this, the free version gets mixed reviews but the pro version (£2.00) get good ones.
Equalizer & Bass Booster
TiTiB (tweak it 'til it breaks ∆ Galaxy Tab S