From Sound Insulation

1.1 Introduction

This opening chapter looks at aspects of sound fields that are particularly relevant to sound insulation; the reader will also find that it has general applications to room acoustics.

The audible frequency range for human hearing is typically 20 to 20 000 Hz, but we generally consider the building acoustics frequency range to be defined by one-third-octave-bands from 50 to 5000 Hz. Airborne sound insulation tends to be lowest in the low-frequency range and highest in the high-frequency range. Hence significant transmission of airborne sound above 5000 Hz is not usually an issue. However, low-frequency airborne sound insulation is of particular importance because domestic audio equipment is often capable of generating high levels below 100 Hz. In addition, there are issues with low-frequency impact sound insulation from footsteps and other impacts on floors. Low frequencies are also relevant to fa ade sound insulation because road traffic is often the dominant external noise source in the urban environment. Despite the importance of sound insulation in the low-frequency range it is harder to achieve the desired measurement repeatability and reproducibility. In addition, the statistical assumptions used in some measurements and prediction models are no longer valid. There are some situations such as in recording studios or industrial buildings where it is necessary to consider frequencies below 50 Hz and/or above 5000 Hz. In most cases it should be clear from the text what will need to be considered at frequencies outside the building acoustics frequency range.

1.2 Rooms

Sound fields in...

Products & Services
Soundproofing and Acoustic Materials
Soundproofing and acoustic materials are used to attenuate, deaden, or control sound and noise levels from machinery and other sources for environmental amelioration and regulatory compliance. 
Passive Filters
Passive filters are implemented using only passive components such as resistors, capacitors and inductors. These filters do not produce any amplification of the input signal.
IC Electronic Filters
IC electronic filters are frequency-selective circuits that consist of devices such resistors, capacitors, inductors, transistors, or operational amplifiers coupled with reactive components.
Acoustic Horns
Acoustic horns are relatively low-frequency horns that produce vibration at frequencies that will loosen and clean soot or other undesirable particulate buildup on chimneys, catalyst beds, or other process vessels.
Audio Transducers and Buzzers
Audio transducers and buzzers are used in electronic equipment, toys and various warning devices as the sounding component.

Topics of Interest

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