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it was not the acoustics that caused the speech to be unintelligible.
    The Reformation of the sixteenth century changed all that: Anglican priests were instructed by the Book of Common Prayer to speak from a place where they could be heard more clearly. 31 Services in English meant that speech would have to be understood. Innovations such as the pulpit in the nave enabled listeners to hear more clearly. There were still reflections, but because the direct speech reached the congregants’ ears quickly and some strong reflections arrived shortly after, the setup tended to aid communication. Late reflections, however, make matters worse.
    Why are some reflections useful and others detrimental? It comes down to how our hearing has evolved to cope with a complex soundscape. In a cathedral, like most places, the ear is bombarded with reflections from all around—from the floor, walls, ceiling, pews, members of the congregation, and so on. In a large cathedral there are many thousands of reflections per second. 32 Perceiving each individual reflection would quickly overwhelm our hearing. Consequently, the inner ear and brain combine the reflections into a single perceived sound event. Thus, when we clap our hands in a room, we usually hear only one “clap,” even though the ear actually receives many thousands of slightly different reflections of the sound in close proximity. A room does not turn a single hand clap into applause.
    The ear is a little bit sluggish, rather like a heavyweight boxer. When the ear receives a very short sound, like a hand clap, or when a boxer is hit by a fast punch, it takes a little time for the system to respond to the stimulus. Both the ear and the boxer also continue to respond after the initial stimulus has gone away: the heavyweight boxer reels and rocks for some time after the punch has landed, and similarly, the hair cells in the inner ear continue to send signals up to the brain for some time after the clap has stopped. On top of this physical sluggishness in the ear, the brain is also constantly trying to make sense of the electrical signals coming up the auditory nerves. The brain employs several tactics to separate the priest’s direct speech from the morass of late reflections reverberating around the cathedral. 33
    If the priest is to one side, the ear nearer the priest receives louder sound waves because the farther ear receives only speech that has bent around the head. The brain thus attends more to the nearer ear, where the speech is louder and easier to pick out among the reflections. Attention focused in this way becomes less effective if there are lots of reflections from many directions, because both ears become overloaded with a wash of unwanted reverberance.
    If the priest is straight ahead, another tactic can be used. In this case the brain adds together what is heard in both ears. The speech coming directly from the priest creates the same signal in both ears because the head is symmetrical, so the sound in each ear has traveled an identical pathway. Adding together the signals from the ears boosts the direct sound. Reflections from the side arrive differently at both ears, and when the left- and right-ear signals are added together, some of the reflections cancel out. This binaural processing increases the loudness of the speech relative to the reverberance. 34
    In big old churches, you often see a small wooden roof (the tester) just above the pulpit. The tester provides beneficial reflections that arrive quickly enough to reinforce the direct sound. The tester also stops the priest’s voice from going up to the ceiling to reverberate and return so late that it makes speech less intelligible.
    Nowadays, loudspeakers are used to improve speech intelligibility in churches. Like the tester, the loudspeakers direct speech toward the audience, improving the ratio of direct sound to reflections. Older systems used many loudspeakers stacked on top of each other