The key instrument . . .
. . . is the room in which all the other instruments are played. Any experienced musician or concertgoer can attest to that, maybe adding a horror story about some room with especially bad acoustics. You might be astonished to learn how many times you’ve heard performers who couldn’t properly hear one another.
Once a hall is built, there’s only so much that can be done to improve its acoustics. Orchestra shells, sound baffles/ reflectors and amplification cannot alter the shape of an auditorium or the materials used in its construction. No enhancement will make a stone or masonry wall (with or without some added interior surface) reflect sound like a wall made of plaster or wood.
Musicians adjust to a sound environment in their articulation and phrasing, and in the quality and mass of tone they produce. In a room with a dull or diffuse acoustic, they try to compensate with brighter, more forward tone production. In a more reverberant space, they rein in instruments such as flute, trumpet and cymbals, whose high-frequency tones can leap out of an ensemble, and they try to bring more warmth to their playing to offset the sonic chill that typically comes with reverberance.
Concertgoers can affect a room’s acoustic, first by showing up or staying away – the more empty seats, the greater the resonance – and, when they do show up, by the clothes they wear. In the concourses around Orchestra Hall in Minneapolis, you find rows of lockers for storage of coats. Minnesotans, by necessity, wear serious winter coats; if they brought them into concerts, that would seriously damphen the room’s acoustic.
The outerwear effect is less pronounced in the more temperate Mid-Atlantic, but you can still detect a difference in a hall’s acoustic in February compared with September or May.
Reasoning that every little bit helps, I try to wear a vest and hat instead of an overcoat when attending concerts in cold weather. If outerwear is a must, quilted jackets of synthetic fibers absorb less sound than wool, flannel or fur coats.