Last week I was walking across a field in France with my wife and her sister and cousins. The five of us are all older than 50 and my ears are now 66. As we walked across the field we noticed that it was full of grasshoppers of all sorts of species. I asked my wife if she could hear them, '"just about" she said. My sister-in-law said that she could hear them everywhere. My wife's cousins could not hear the grasshoppers either. Even when I cupped my hands over my ears I could not for the life of me hear a grasshopper.
Grasshoppers stridulate at 10 KHz or above. The older members of our group therefore had problems hearing high frequencies.
Later on we did a very non-scientific test of our hearing by downloading some test frequencies. My wife's sister could easily hear a 12 KHz tone. The rest of us had problems though but my wife's younger nephew could hear above 15 KHz.
When I returned to London I tested myself again in the quite of my office. Through headphones I could easily hear a 8 KHz tone; but I had to turn up the volume to hear 10 KHz and 12 KHz tones. I could not hear a 14 KHz tone even with the volume turned up full.
You may well ask "what has this got to do with Hi-Fi?". Well the generally accepted range of hearing for frequency in humans is 20 Hz to 20 KHz. This range is for younger people only; for as we get older our ability to hear the higher frequencies diminishes. Luckily, I can still hear the difference between a clarinet and an oboe when listening to an orchestra live. This is because I can still hear the principle harmonics of both the oboe and the clarinet as they are lower than the 8KHz limit that I am still able to hear clearly. A CD can reproduce sound between 20KHz and 22 KHz . The upper limit is far beyond the hearing capacity of most people even children. An LP record really starts to tail off its frequency response at 15 KHz; but its upper frequency response is still above what most people in their 40s and over can hear easily.
You may ask yourself why older audiophiles are prepared to pay big sums of money for moving coil cartridges that can reproduce frequencies well above the limit for human hearing. You may ask why some older audiophiles insist that they can hear differences between CD quality music files and "HIRES" music files when all other parameters are equal. A 24/96 "HIRES" music file can reproduce a tone of 48 KHz!
Why do we need DACS, speakers and amplifiers that are capable of reproducing frequencies that no-one can hear? We would not produce a television system that could broadcast UV light as it would be a complete waste of resources, so why do it with Hi-Fi? Some Hi-Fi enthusiasts are being confused by a numbers game.
You may well ask why older Hi-Fi journalists have somehow defeated the ravages of time so that they can really distinguish between PCM, DSD and MQA. And why they don't need to turn up the volume to listen to the grasshoppers just like the rest of us old ones.
