Rafał Blechacz is planning to give several recitals in my country early next year. In most cases he will play at large concert halls (as usual here) to accommodate many music fans, but the tour has a recital at a small chamber music hall in western part of the country which is renowned for its excellent acoustics. The following is an evaluation of the hall written by an expert of acoustics several years ago.
.....This chamber music hall is small with just 200 seats. But when I look at the stage from the back of the room, the ceiling is high and the spatial atmosphere is that of the middle-sized concert hall. Acoustics system is not high-profile; the side-walls are inward inclined a little, containing the curtains for adjusting reverberation. I love the neatness with no unnecessary decoration. But an air vent on the ceiling was distractive. I was seated right and back of the room. The program was for singing accompanied by piano, a program requiring clearness. I was impressed by the nice balance between reverberation and clearness. The sound was nicely delineated but not provocative. A well-balanced, lucid sound was delivered from low through to high registers.
In case of a small hall like this, how to secure the early reflected sound isn't a challenge, unlike large concert halls. However there is another issue that most of the audience members are seated close to the sound source. Depending on the types of instruments and formation, the range of volume and sounds are varied. So it is difficult for a designer to determine where to place a focus of reverberation. In designing a small hall, one concern is diffusion of sound field. Currently the relationship between the sound diffusion and acoustics has not been elucidated. The only countermeasure of sound diffusion taken by this hall is the slightly inclined walls (at 5 degrees) and gentle curving of the ceiling. But I thought the sound was never acute. It's partially because I was seated at the back of the room. I felt the sound balance of this hall was really excellent. It was helped by the performers who knew how to play here.
In later days, one of my colleagues attended a piano recital by Alexis Weissenberg here. He said that he couldn't hear details of the performance; it echoed round and round. I heard the same artist's recital at Suntory Hall and The Symphony Hall in Osaka and had similar impression. That way of performing was not suitable for this small hall, which has narrower tolerance to volume.... Anyhow for me this is the hall that suggests many things to learn.