I was having the same issue for a while. The only thing that fixed it was getting a new battery. I got an anker replacement battery. Actually 2 of them plus a battery charger for $28.00 on amazon.
You can use OK Google, (which in my opinion is better than s voice). You can set OK Google to activate from any screen even if your phone screen is off. Perfect for hands full use.
I've been using gentle alarm for several years . It hasn't failed me yet. You can set your own tones or use some of their own nature sounds. I never turn my alarm off, it is always set and ready to go.
Re: Fives days, five free phones: Win with Android Central, Poweramp and Negri Electronics!
I really need a new phone My GS3 is reaching it's end. Hook a brotha up!!