Noise after changing timing belt, balance shaft??

So last Friday the car sputtered out and died on me. Come to find out, the timing belt was missing a bunch of teeth in one area. So I had the timing belt replaced, along with the water pump. Now I notice when I start it cold and it idles high to warm up, it sounds like I have subwoofers under the hood. Soon as you put it in gear, the rpms drop and it goes away. Then when your driving it isn't that bad, except when you let off the gas, it sounds like the bass hits again. Cruising around with a little throttle the engine sounds great.

I've been searching forums and videos on youtube about the front balance shaft being off since it's geared 3:1 and a common problem but wouldn't that make the engine vibrate rough constantly? And out of all the videos I've seen so far, the engine rattles like a diesel. The galant is completely stock except those silicon radiator hoses, that add 50 horsepower. j/k I'm loading a video of the cold start this morning...
Thanks for any help

https://vimeo.com/151608577

either when the timing belt broke some teeth off the valves hit the pistons and its running rough.....(worst case scenario)

or when whoever replaced the timing belt and balance shaft belt, they didnt time one of the balance shaft belts correctly.

believe it or not there are 2 balance shaft belts, one to the left of the crank(the one the balance shaft belt goes to) and one behind the oil pump. the one behind the oil pump MUST be timed correctly when putting the timing belt on, even though the marks may be lined up the balance shaft will not be lined up. the only way to make sure it is in time without removing the oil pump is to pop a bolt out of the side of the block and insert a screw driver into the hole far enough to hit the balance shaft and then some.

99% of the time when i was working at a Kia dealership, when i got an optima in with an engine vibration, they usually just had a timing belt done at an independent shop and they obviously didnt know about this little trick.