Instrument radiation patterns vary by frequency, shaping both stage reflection and audience blend

Evidence

Musical instruments radiate sound in all directions with many frequency-dependent directional patterns. High frequencies from violins radiate vertically away from the top plate of the instrument, while other frequencies radiate in other directional patterns. Those from a trumpet project strongly outward from the bell of the instrument. Other instruments may radiate almost omnidirectionally, or with a pattern of a dipole radiator (figure eight) over different frequency ranges. In a concert hall, one of the functions of the stage enclosure and the immediate surroundings of the orchestra is to collect these sounds and reflect some of them back towards the musicians so they can hear each other. The other function is to communicate a blended mixture of orchestral sounds into the audience through the reflected, relatively diffuse, sound field. — Toole, Floyd E, Sound reproduction- the acoustics and…, 375