Acoustics in Buildings

1. In designing a concert hall or theatre the architect not only has to take into account¹ the number of people to be seated and the arrangement of the seats in relation to one another, the position of doors and details of ventilation and illumination. He should also give careful consideration to² the acoustics of the building.

2. Sound waves are known to travel in straight lines. They go out from their source in all directions. In much the same way as with light, sound waves can be reflected or absorbed by surfaces which they strike.

3. As the sound absorption properties of a particular substance vary for different frequencies, it is desirable that sound should have a free path from the source direct to each member of the audience. For this reason pillars and other obstacles in the halls should be avoided if it is possible.

4. The final tonal quality of the sounds largely upon the portion of the sound waves reaching the listener by reflection. Each time a sound wave is reflected, some of the sound is lost due to absorption. Thus after it has been reflected a few times, the sound will die away³ completely. There will always be a slight time lag⁴ during which the sound gradually dies away even if the source is stopped suddenly. This time lag for concert halls of moderate size is known to be about 2 seconds.

5. The extent of the reflections will depend not only upon the shape and size of the auditorium, but also upon the nature and relative proportions of the reflecting and absorbing surfaces. Irregularities in the walls and ceilings can cause unwanted reflections and are to be avoided. The form and height of the roof of the concert hall have to be carefully chosen in order that the sound waves it collects could be reflected back over as large an area of the auditorium as possible.

6. At the design stage the architect has to check the acoustic properties of a concert hall by means of calculations based on the reflection of sound. The improvements in the acoustics will depend largely upon the interior decoration of the hall.

7. Various reflectors may be attached to the walls and ceilings to turn the sound waves in the most desirable directions. The acoustic properties of paints used for wall coverings are at least as important as their decorative value. The use of carpets on the floors, of absorbent materials on the walls and cailings and of suitably upholstered⁵ seats will help to solve this problem.

Notes

¹to take into account - принимать во внимание

²to give consideration to - уделять внимание чему-либо

³to die away - затухать

⁴time lag - запаздывать

⁵to upholster - обивать мебель

VII. Выпишите из текста предложения, содержащие следующие грамматические формы и обороты: из 2-го абзаца – предложение, содержащее страдательный залог; из 5-го абзаца – предложение, содержащее бессоюзное подчинение. Переведите эти предложения на русский язык.

VIII. Прочтите 7-й абзац и вопрос к нему. Из приведенных вариантов ответа укажите номер предложения, содержащего правильный ответ на поставленный вопрос:

What helps to improve the acoustics of a concert hall?

1. the decorative value of wall coverings...

2. absorbent materials on the walls...

3. the use of pillars in the hall...

Вариант 3

I. Переведите предложения на русский язык, определите в каждом из них видо-временную форму и залог глагола-сказуемого.:

1. The delegates will be met at the station.

2. Scientists have worked out special equipment for this purpose.

3. Splendid new buildings have changed the city’s appearance.

4. Beautiful houses of concrete and glass are being built in our district.

II. Переведите следующие предложения, учитывая разные значения слов it, that, one:

1. Everybody knows this man.

2. This book is more interesting than the one we read last week.

3. There is a new machine in our shop similar to that described in the magazine.

4. You must close the window for it is rather cold.

III. Перепишите предложения и переведите их, имея в виду различные значения глаголов to be, to have, to do:

1. She did not come because she was ill.

2. Your task is to do your work well.

3. He is to finish this experiment by the next Monday.

4. They had to bring the results of their work yesterday.

5. They have much work to do.

6. Do they like visiting exhibitions?

IV. Перепишите следующие предложения обращая внимание на бессоюзное подчинение:

1. He said he would not be able to come.

2. My friend told us he had taken part in the construction of that power station.

V. Перепишите следующие предложения и переведите их, обращая внимание на функции инфинитива:

1. This new method can be used to produce houses of any number of storeys.

2. To design the plans of buildings is the work of architects.

VI. Прочтите и устно переведите 1-4-й абзацы текста. Перепишите и письменно переведите 1 и 2-й абзацы: