Contenido

El tiempo de reverberación (TR) es un parámetro que se utiliza para cuantificar la reverberación de un determinado recinto. Se define como el tiempo que transcurre —hasta que decae a una determinada intensidad — las reflexiones "Reflexión (sonido)") de un sonido directo.

Habitualmente, para medir el valor se considera que las reflexiones finalizan cuando la intensidad con la que se perciben es una millonésima de su valor original, lo que equivale a 60 dB. La medición se realiza emitiendo un ruido corto y seco en el recinto y registrando cómo evoluciona la intensidad con la que se percibe.

Estimation of reverberation time

Various mathematical tools have been developed to estimate the reverberation time that a specific room would have. One of the most used and simplest is the Sabine formula. Physicist Wallace Clement Sabine developed it to calculate the reverberation time of a room in which the absorbing material is uniformly distributed. The formula relates this time to the volume "Volume (physics)") of the room (V), the surface of the room (A) and the total sound absorption "Absorption (sound)") (a):.

Sabine's formula can be improved by introducing an air absorption factor (x) based on temperature and humidity. This factor is of great importance when it comes to large venues.

Sabine's formula is usually used only as an estimate. Other formulas used to calculate this value are the Eyring formula and the Millington formula.

The ideal reverberation time

Reverberation in a room significantly modifies its acoustic qualities. For the loudness to be adequate, the time should not be high or low, but rather adjusted to the use that the room will have. Thus, rooms with low or "dry" times may be suitable for theater or spoken word but not suitable for listening to music. At the same time, various genres of music require different tempos, generally much longer than what is considered optimal for the word. All this makes it very difficult to find multipurpose rooms, although using various techniques it is possible to "tune" a room or vary its reverberation time.

The volume of a room directly determines (along with other factors such as its materials) the reverberation time. Optimal time is a function of volume, and longer optimal times are generally preferred when rooms are larger, and vice versa.

Empirically, the following are considered approximate optimal times for the 500 Hz frequency band, in relation to the use of a room:

In particular, sacred music requires higher values ​​because it is generally associated with venues such as cathedrals, which tend to be highly reverberant.

Although the use of an anechoic room is the only way to perceive a certain sound material reproduced within it without any added coloration or reverberation, they are not suitable for most situations. Speakers, singers, and theater actors need a certain reverberation to hear themselves (in the absence of some type of monitor). The time of the first reflection should not be excessive, especially in large groups such as orchestras or choirs, to maintain end-to-end synchronicity of the ensemble. Soloists prefer long reverberation times, as this favors the feeling that their emission is done efficiently and effortlessly, but if the type of music is fast, the reverberation time should be relatively short to avoid sonic confusion between successive notes and chords. Thus, there is a compromise between the versatility of a room, or suitability for different uses, and the reverberation time it presents depending on its size, shape and type of covering materials.

"Tunable" rooms are those that allow the reverberation time to be modified. Techniques to make a room more streamlined consist of the use of "clouds" or hanging panels that can be oriented in different positions, absorbent curtains that can be drawn up to reveal a reflective wall behind them, and panels with a different coating on each side, absorbent and reflective, that can be turned over to show only one side.

It is likely that the sensation of reverberation in our brain is associated with the warmth and security that primitive man felt millions of years ago, when he protected himself in caves and lived daily with this acoustic phenomenon. (Rene Moris, AIEP Vina del Mar Institute).

Contenido

El tiempo de reverberación (TR) es un parámetro que se utiliza para cuantificar la reverberación de un determinado recinto. Se define como el tiempo que transcurre —hasta que decae a una determinada intensidad — las reflexiones "Reflexión (sonido)") de un sonido directo.

Habitualmente, para medir el valor se considera que las reflexiones finalizan cuando la intensidad con la que se perciben es una millonésima de su valor original, lo que equivale a 60 dB. La medición se realiza emitiendo un ruido corto y seco en el recinto y registrando cómo evoluciona la intensidad con la que se percibe.

Estimation of reverberation time

Various mathematical tools have been developed to estimate the reverberation time that a specific room would have. One of the most used and simplest is the Sabine formula. Physicist Wallace Clement Sabine developed it to calculate the reverberation time of a room in which the absorbing material is uniformly distributed. The formula relates this time to the volume "Volume (physics)") of the room (V), the surface of the room (A) and the total sound absorption "Absorption (sound)") (a):.

Sabine's formula can be improved by introducing an air absorption factor (x) based on temperature and humidity. This factor is of great importance when it comes to large venues.

Sabine's formula is usually used only as an estimate. Other formulas used to calculate this value are the Eyring formula and the Millington formula.

The ideal reverberation time

Reverberation in a room significantly modifies its acoustic qualities. For the loudness to be adequate, the time should not be high or low, but rather adjusted to the use that the room will have. Thus, rooms with low or "dry" times may be suitable for theater or spoken word but not suitable for listening to music. At the same time, various genres of music require different tempos, generally much longer than what is considered optimal for the word. All this makes it very difficult to find multipurpose rooms, although using various techniques it is possible to "tune" a room or vary its reverberation time.

The volume of a room directly determines (along with other factors such as its materials) the reverberation time. Optimal time is a function of volume, and longer optimal times are generally preferred when rooms are larger, and vice versa.

Empirically, the following are considered approximate optimal times for the 500 Hz frequency band, in relation to the use of a room:

In particular, sacred music requires higher values ​​because it is generally associated with venues such as cathedrals, which tend to be highly reverberant.

Although the use of an anechoic room is the only way to perceive a certain sound material reproduced within it without any added coloration or reverberation, they are not suitable for most situations. Speakers, singers, and theater actors need a certain reverberation to hear themselves (in the absence of some type of monitor). The time of the first reflection should not be excessive, especially in large groups such as orchestras or choirs, to maintain end-to-end synchronicity of the ensemble. Soloists prefer long reverberation times, as this favors the feeling that their emission is done efficiently and effortlessly, but if the type of music is fast, the reverberation time should be relatively short to avoid sonic confusion between successive notes and chords. Thus, there is a compromise between the versatility of a room, or suitability for different uses, and the reverberation time it presents depending on its size, shape and type of covering materials.

"Tunable" rooms are those that allow the reverberation time to be modified. Techniques to make a room more streamlined consist of the use of "clouds" or hanging panels that can be oriented in different positions, absorbent curtains that can be drawn up to reveal a reflective wall behind them, and panels with a different coating on each side, absorbent and reflective, that can be turned over to show only one side.

It is likely that the sensation of reverberation in our brain is associated with the warmth and security that primitive man felt millions of years ago, when he protected himself in caves and lived daily with this acoustic phenomenon. (Rene Moris, AIEP Vina del Mar Institute).