My volume on my tv goes up and down?

I just bought a new tv a sceptre and when were watching the volume goes low then high what’s wrong with it?

TV menu -> Audio options -> try turning off surround sound off -> and I always leave stable sound on.

– I like it when surround sound is on, it sounds better than when off.
Volume Goes Up And Down
I took off the back of my TV, disconnected the wires leading to the volume board on my TV (top and bottom wires). I reconnected them back and no more volume control problem. It was a very simple fix which I am sure a TV repair man would of charge me anywhere from $150 to $300
go to menu then sound and turn off the AVL, its an auto volume leveler

Source(s): i own a sceptre X405-BV HDTV with the same options
Same problem and i have tried these solutions but it wont let me control the tv/