Audio Quality Measurement Technologies for Engineering and Manufacturing
What can upset your few minutes of downtime, kicking back with the sounds of your choice?
It’s a good day and you are home listening to your favorite playlist on your mobile that is hooked to a smart speaker you just bought a week ago. But, there is something pinching about the music quality. The sound of the speaker is garbled and you are confused why the device isn’t working the way it was written in the specifications. Maybe, there is some issue with your mobile phone or the smart speaker has poor quality audio streaming or there is interference or a systematic problem with your Bluetooth link.
The Component Parameters of Audio Quality
The main purpose of a smart speaker is to provide high quality audio free of noise and sound impairment effects. The expectation of a high-quality audio system is to provide:
- a frequency response beyond the range of the human ear
- imperceptible echo
- no discernible distortion
- music that can be heard either soft or loud depending on the requirements of the original content
- noise cancellation of a perceptible degree
- low delay (i.e., no variation of delay within a soundtrack and no perceptible lip sync issues if the audio is accompanying a video)
If the smart speaker audio quality is deficient in any of the six facets above, then not only will it cause trouble to the listener but will also affect the reputation of the manufacturing company.
Bluetooth
It is also a possibility that the Bluetooth link degrades the voice transmission quality. Errors and memory leaks could exist within the chipset and the channel used by the Bluetooth wireless connection could be used by other Bluetooth connections in the vicinity. It is essential for the manufacturers to test the quality of the sound between their product and the Bluetooth-connected mobile phone. When you, the manufacturer, are measuring the sound quality in an audio or speech file, it is essential that the test equipment itself is free of any error and introduces zero impairments itself. This means that the dynamic range and frequency response of the test equipment must be significantly superior to that of the test system. Otherwise, the accuracy of the measurement will be adversely impacted. Read more about audio dynamic range testing.
Frequently Occurring Problems
Problems frequently occur at the chip level so testing by semiconductor manufacturers is essential. In addition to that, integrating an audio subsystem into a smartphone or smart speaker requires a delicate balance between computer resources allocated for audio quality versus other applications operating on the device. It is necessary to test the audio device in the lab emulating conditions frequently encountered in the field such as background noise and echo.
Measurement Technologies for Engineering and Manufacturing
It is also necessary to measure the audio streaming performance during the manufacturing phase over long periods of time to detect systematic errors. when encountered later, these are costly to resolve in the field after product release. Standard objective measurement methods are used in order to compare on an even playing field, other speaker devices which have good sound reviews from users. Objective measurement methods made by a computer versus subjective assessments made by humans listening to audio clips are much cheaper, more consistent, and repeatable. Such a metric for audio signals is PEAQ audio quality defined under International Telecommunication Union (ITU) recommendation ITU-R BS.1387.
Increasing Use of Wearable Audio Technology
With the growing popularity of wearable audio technology and smart speakers, it will become more important to measure the quality of other forms of audio in addition to speech quality.
Speech quality, as opposed to audio or music quality is well measured in the telecommunications industry by the POLQA International Telecommunication Union (ITU) recommendation ITU-T P.863 standard. However, the need for accurate analog test equipment still applies to speech quality measurements. Read more about why voice testing matters.
Quick and Accurate Method for Measuring Audio Music Quality
The video below shows how easy it is to measure music quality through any device using the Opale Systems MultiDSLA and an audio test file played from a mobile.
