What is IEC 60268-4

IEC 60268-4 is a technical standard that provides guidelines for sound system equipment, specifically public address and sound reinforcement systems. It covers the measurement methods and performance criteria related to the sound systems used in settings like concerts, theaters, stadiums, and public spaces. This article aims to explain the key aspects of IEC 60268-4 in an easy-to-understand manner.

Guidelines for Sound System Equipment

The standard defines several parameters for measuring the performance of sound system equipment. These include frequency response, distortion, sensitivity, signal-to-noise ratio, and dynamic range. Let's take a closer look at each of these parameters:

Frequency Response

Frequency response refers to how well a sound system reproduces audio across different frequencies. A flat frequency response means that the system accurately reproduces sound at all frequencies without emphasizing or attenuating any particular frequency range. The standard provides guidelines for acceptable deviations from a flat response, allowing engineers to assess the quality and consistency of a sound system's performance.

Distortion

Distortion measures any unwanted changes that occur to an audio signal as it passes through the sound system. Distortion can be caused by various factors, such as non-linearities in amplifiers or speakers. The standard sets limits on both harmonic distortion (related to the introduction of harmonics) and intermodulation distortion (related to the mix of multiple frequencies), ensuring that the sound system accurately reproduces the original audio source without additional noise or artifacts.

Sensitivity

Sensitivity defines how loud a sound system can reproduce sound for a given input level. It measures the sound pressure level (SPL) produced by the system when driven by a particular power or voltage. The standard specifies the test conditions and methods to determine sensitivity, allowing users to compare different sound system equipment based on their output capabilities.

Signal-to-Noise Ratio

The signal-to-noise ratio (SNR) is a measure of the desired audio signal level compared to the background noise level generated by the sound system itself. A higher SNR indicates a cleaner and more accurate reproduction of the original sound source. The standard establishes guidelines for measuring and reporting this ratio, making it easier for users to evaluate the noise performance of different equipment.

Dynamic Range

The dynamic range represents the difference between the loudest and softest sounds that a sound system can reproduce without distortion or overload. It is an essential parameter for capturing the full range of audio content, from subtle nuances to intense peaks. The standard specifies the methodology for measuring the dynamic range accurately, enabling engineers and users to understand the system's capabilities in handling sound variations across different scenarios.