Theater is the name for it. One of the most famous ones, still in good repair, is at Epidauros. An amphitheater is a Roman, not Greek, invention.
In concert halls the walls are made out of acoustic materials. The materials, as well as the amplifier may result in multiple echoes in a concert hall.
Oxford
7000
Well I saw him in September 1975 at De Montfort Hall
George Harrison
Thessaloniki Concert Hall was created in 2000.
Vigadó Concert Hall was created in 1859.
Video Concert Hall was created in 1978.
Sapporo Concert Hall was created in 1997.
Ermitage - concert hall - was created in 1914.
Maverick Concert Hall was created in 1916.
Limoges Concert Hall was created in 2007.
Oslo Concert Hall was created in 1966.
describe the high ceilings, the organ, the seating, and etc.
In Concert-Carnegie Hall was created on 1975-01-11.
Town Hall Concert was created on 1964-04-04.
From Coffee House to Concert Hall was created in 1999.