a. That song was the first time such effects had been used in music history.
b. That song was the first time such effects were used in music history.
Which of the two sentences is gramamtically correct?
The effects were used in that song. It was the first time such a thing was done.
I think (b) is correct because the effects were used in that song. But I am not sure. I can't see the logic behind (b). Why would one use the past participle? But then again, it doesn't sound wrong to me for some reason!