Occasional posts on subjects including field recording, London history and literature, other websites worth looking at, articles in the press, and news of sound-related events.

07 January 2013

Reverberation and Authority

THE GREAT AND Powerful Oz manipulated his voice to give it the authority of reverberation:

Oz set the tone for disembodied beings in series like Star Trek and its British derivative Space: 1999. The reverb voice is ideal for telling viewers you’ve slumbered for thousands of our years but can now feel again and live again, before getting the hots for a crew member.

The trope works because the listener already associates reverberation of speech with power. Journalists reach for tired phrases like those ringing condemnations and ringing denunciations which reverberate throughout the land. It contains the idea that the speech reverberates because it’s as if it were made by someone speaking inside a large stone-walled building. You only get to make such speeches if you’re important, and to be important means people listen to you and take heed.

Reverberation is the sound of a stampede of echoes in a confined space, each separated by around one millisecond or less. The time it takes the reverberation to fade away depends on the size and shape of the confining structure and what it’s made of.

Acoustic engineers can record impulse responses: the characteristic responses of different spaces to sound. Impulse responses can then be mathematically modelled and applied to audio signals to give them the reverberant qualities of a garage, a concert hall or a mineshaft.

These are three simulations of the impulse responses of an 18th-century salon, the Scala opera hall in Milan, and St Nicolaes church in Amsterdam:

The last of the three sounds slightly unusual, with a kind of frothy hiss to the reverb’s decay. Here they are plotted as spectrograms:

Spectrograms of three different impulse responses

Blind people use the reverberant qualities of streets to help build mental maps of the environments they’ll become familiar with. They can also make and attend to impulse responses of their own by tapping their canes.

The reverberance of a street tells you something about its status too, at least here in London. Many thoroughfares in central London are narrow and flanked by high buildings. The sounds of car horns and the noisy engines of motorbikes and hackney cabs take on a quality that you don’t hear in the suburbs, where buildings are lower and roads wider. The financial district of the City of London has this effect even more strongly because of its tall office blocks. Perhaps that’s the sound signature of all financial districts worldwide.

Financial institutions are now strong enough to play games with governments, so it seems appropriate how their part of town has taken on the mantle of reverberant authority. Meanwhile politicians opt for conversational tones on breakfast telly sofas. The age of the formal stance in speech is now almost over, like the dignified way people posed in old photographs.

In a BBC recording from 1937, a new Lord Mayor is elected at the Guildhall. This extract has an official called the Common Crier begin the proceedings. Note how he pauses between each utterance of oyez! to allow the reverberation of his voice to be heard:

The effect doesn’t work outside the environment which produces it. This man was preaching in Brixton with the aid of a battery-powered PA and he’d turned up the reverb effects dial. But he has no more authority than Oz did once the curtain was pulled back:

Reverberance is not a charismatic quality that people carry around with them wherever they go, like you can a deep voice. It is part of its setting and the assumption is that the speaker has the right to be there.

The power of reverberance accords with the conservative belief that authority is immanent in institutions.