A concert hall is the instrument that all musicians “play.” Whether produced by bowing, blowing, plucking, striking, or phonating, a great hall brings sonic personality to the distinctive timbre of an instrument. And the personality of a hall is dependent on its acoustical properties.
It is an interesting fact that the highest-rated concert halls of all time were the ones built before 1900. Their secret—rectangular or shoebox shaped, with hard surfaces often quite ornate and with lightly upholstered seating. Often considered the best in the world is the Musikverein in Vienna, Austria. This ornate 1,744 seat hall opened in 1870."This certainly is the finest hall in the world," said revered conductor Bruno Walter."It has beauty and power.
2) Sufficient early sound reflections so you are hearing the sound a few milliseconds after it is played. To achieve this, the sound is being reflected only once or twice from ceilings, walls, and floors.