That theater is a treasure. It was built as a theater originally about the time of the stock market crash; it's just owned by a church and has been used for that purpose since they bought it for a song at maybe $250,000 in perhaps the 1970's.
It is one of the most beautifully designed theaters in the city, by Charles Lamb, easily more beautiful than many Broadway houses. It has a grandeur all its own.
The acoustics are excellent, though I hope they've carpeted the floor now, which was just painted concrete under the seats when I saw and explored it . They have concerts there.
I don't agree with Reidel that its architecture is Moorish. I found it more Byzantine than anything in its main architectural style. Perhaps Reidel is thinking of the Christian Byzantine churches which were both seized and copied by the invading Turks. Notice the similar use of Romanesque arches and design as in Lamb's theater. The Islamic invaders copycatted the Byzantine style Christian Churches, as in the "Blue" mosque. There are other styles of architecture which are more original to the Moors/Islamics and are considered Moorish, like some of the castles in Spain including the Alhambra.
Incidentally, a beautiful example of Byzantine architecture in New York City is St. Bartholomew's Church, well worth a visit.
Look down to see St. Sophia Byzantine Christian cathedral seized and usurpt by the Turks as a mosque and another copycat mosque