Measuring audio gear is a crucial step in ensuring optimal sound quality. THD+N (Total Harmonic Distortion plus Noise) is a key metric that measures the amount of distortion and noise present in an audio signal. Distortion refers to the alteration of the original signal, while noise refers to the unwanted sounds that can degrade the
Another important metric is SINAD (Signal-to-Noise and Distortion), which measures the ratio of the desired signal to the unwanted noise and distortion. A higher SINAD value indicates better sound quality. FR (Frequency Response) is also a critical metric, as it measures the range of frequencies that an audio device can produce. A flat FR curve indicates that the device can produce all frequencies equally, resulting in a more accurate sound.
Understanding phase and its importance
Phase refers to the timing relationship between different frequency components of an audio signal. In an ideal scenario, all frequency components should be in phase, resulting in a coherent and accurate sound. However, when different frequency components are out of phase, it can result in a distorted and unclear sound.
Measurement rigs and room effects
A measurement rig is a setup used to measure the performance of audio gear. It typically consists of a signal generator, a measurement microphone, and analysis software. The rig is used to measure various metrics, including THD+N, SINAD, and FR. However, the accuracy of these measurements can be affected by room effects such as reverberation and echo. To minimize these effects, measurements are often taken in an anechoic chamber or using specialized equipment.
Blind listening correlations
Blind listening tests are used to correlate measured performance with perceived sound quality. In these tests, listeners are presented with different audio signals, without knowing which signal is being played. The results of these tests can help identify which metrics are most closely related to perceived sound quality. For example, research has shown that THD+N and SINAD are strongly correlated with perceived sound quality, while FR is less closely related.
Guidance on balancing objective data with perceptual evaluation
While objective measurements are essential in evaluating audio gear, they should be balanced with perceptual evaluation. This involves listening to the audio gear and subjectively evaluating its sound quality. By combining objective measurements with perceptual evaluation, audio engineers and enthusiasts can gain a more comprehensive understanding of an audio device’s performance and make informed decisions about its suitability for a particular application.
