DAL 1125 757 if I remember right. We were #2 behind them when they declared an emergency. They announced that they were going around probably around 5 mile final on 9L. Tower gave them rwy and 3500 or 4000'. Then DL1125 declared an emergency. It was the female pilot talking all the way up to this point. Lots of alarms going off in the background anytime she transmitted. The male pilot came on shortly there after restated the declaration of an an emergency, said they were going to level off at 3000' and that they needed to come back to the airport immediately. Both pilots sounded very strained when they made their calls on the radio. Something must have gone oh $hit! wrong for a minute or two. The twr sent us around then changed his mind, asked if we had the field and cleared us to land. They came back and landed maybe 5-6 behind us. When they were back on with twr the female pilot's voice sounded normal again and they landed uneventfully. There was holding before this happened anyway, I think we did 2-3 turns. The same DL flight told ATC that the had about 12 mins left before they had to bug out to Huntsville from the hold. ATC promptly put them on a vector for HSV. After a minute or 2 ATC came back and said that the low controller could work them in and turned them back to ATL.