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A question of quality

In this week's focus on research, the Prof looks at what's really important in terms of audio quality from a consumer's perspective.

As a sound engineer, it’s easy to get depressed when you think about the average consumer’s appreciation of audio quality. You’d probably like to think they care, but you wonder whether they do, and maybe you try not to think about it too hard because otherwise you’d give up and become an accountant. Somewhere in your mind is perhaps an image of the person you hope will be listening to your mixes. He (and it is almost certainly a he) sits in a good stereo seat in a nicely treated living room, with a pair of B&W Nautilus loudspeakers (yes, only two) and a Meridian CD player or a Linn Klimax digital stream player. It is a fact, though, that younger people in particular mainly listen to data-reduced music on headphones through portable music players, and the car is another important context. So what do we know about consumer attitudes to different aspects of sound quality? Not just what consumers hear, mind, but what they think is important. Ainslie Harris is completing a doctorate in business administration, exploring consumer behaviour and attitudes in relation to music download services. In an engineering brief, presented recently to the AES in London, she asked whether young people really care about the quality of their MP3s. She found that there was a clear age boundary at about 25. Those of her focus group participants who expressed a preference for higher quality downloads were generally older than this, and it seemed to apply whether they were getting the files free or paying for them. Indeed a number of this group seemed genuinely frustrated that they couldn’t purchase higher quality downloads, or didn’t know where to get them. Those above 25 that didn’t care said that they were mainly listening on iPod-style headphones, and that the replay equipment wasn’t good enough to make it worth having higher quality audio. 15–17 year-olds mostly didn’t know much about sound quality or bit rates and said things like “you wouldn’t need the quality to be 100% as long as it’s clear and you can hear everything”. Whether or not you notice aspects of sound quality could be largely a matter of training (although this is a controversial topic). When I ran a research group at the University of Surrey that specialised in sound quality evaluation, we did some experiments comparing typical consumers’ and trained listeners’ appreciation of surround sound quality. It became quite clear that having accurate frontal stereo imaging made very little difference to the consumers’ preference for one version over another. What mattered more to them was an enveloping spatial effect. For the trained sound engineers it was the other way around. One could say that the sound engineers had been trained to notice changes in stereo imaging and to regard it as important, but that this wasn’t typical of the general population. Harris’s research found that people working in the music industry (interestingly, on either the business or the engineering sides of the fence) preferred uncompressed file formats. DJs tended to want to use MP3s with bit rates higher than 320 kbit/s. So perhaps it’s a case of “the more you know, the more you want” (or the more you believe you need). There is certainly a trend towards making available higher resolution downloads in some niche areas of the market, and charging people considerably more for the privilege. These often seem to outsell the lower resolutions by a considerable margin. That they may be played back on audio systems incapable of realising the quality improvement is sad, but hey, have you seen the emperor’s new clothes?