Opinion - Your letters
Feedback: Your letters
Do audiophiles know best?
I was interested to read that loudspeaker manufacturer Bowers & Wilkins trusted the ear of its master listener more than it trusted a spectrum analyser and a calibrated microphone when designing equipment for the new Jaguar XF ('Good vibrations', Vol 3 #4).
The belief that the human ear and brain are a better and more consistent measurement tool than any other available seems to be common in the hi-fi community.
Could it be that the ear/brain is really such a sensitive combination? If so then there are a number of things known by the hi-fi community that common sense, theory and engineering have missed, and which maybe we should be using to improve engineering instrumentation.
For instance, that spending £200 or more on each mains lead will bring genuinely audible improvements to even the best stereo equipment, especially if the plugs and sockets are rhodium plated. Whereas at work we'll happily exchange leads between the test equipment and the kettle.
That speaker and interconnection cables with identical connectors at both ends and with no directional screening arrangement will nevertheless work better in one direction than the other. And even if the cables are not directional when bought, they will become so with use. Whereas the professional quality cables I recently bought for running 100kHz signals the length of a rail vehicle bear no indication as to which end is which.
That even solid-state electronics benefit significantly from being mounted on a vibration-free support system (glass shelves, well known for their vibration-damping abilities, supported on sharp spikes apparently being best). So no more wooden test benches with data recorders held down firmly with strapping.
Screened mains cables will possibly radiate lower levels of electromagnetic interference into nearby electronics and cables; conceivably the microphonic effects of coupled vibration could be heard (though flicking the signal cables feeding my 50W amp results in no sound from the speakers whatsoever, provided the other end of the cable is connected to a low-impedance source) but what's going on with the directional cables?
Are we engineers, with our calibrated test equipment and serial processing analysis machines (aka PCs running Matlab), missing something that the super sensitive ears and neural network brain of the master listener know to be true? Or is someone pulling the hi-fi consumer's leg?
Nick Arran CEng MIET, Derby
Understanding the brain
I was fascinated by E&T's 'Brain Issue' (Vol 3 #5), but feel the understanding of 'brain' was limited. The brain evolved to optimise survival. All of the discussion centred on the conscious thought which represents about 25 per cent of activity and is not a separate part of the brain but part of the parallel processes of the whole.
Because it is a slow processor compared with electronic processors, it compares new sensor information with its stored models and only looks for changes or movement. The one thing it is not interested in is static information. Processing differential information allows it to throw away 90 per cent of the input information and take rapid decisions.
Furthermore the brain is an adaptive complex system that is continually remodeling its connections and information so that today's brain is not the same as yesterday's brain or for that matter anyone else's brain. Being non-linear means that the output cannot be predicted from the input - 'free will'.
Modelling the complete brain is a meaningless exercise as it is only useful to a functioning human being, but understanding some of its processing ability could lead to new directions in computing. Perhaps the most useful functions to study in these days of massive information overload are how to throw away 90 per cent and still get the right answers most of the time, and also how to work continuously for 80-90 years and degrade gracefully in spite of damage.
Paul Richards FIET, by email
I have noticed with interest the debate in E&T's 'Feedback' pages on language learning. I speak as someone who has been learning a second language for a considerable number of years (first French and now German).
Do people really understand how difficult is for UK residents to learn a second language? Just try to go to your local newsagent and pick up a German or French newspaper, let alone a Chinese one. Try travelling to say, the Netherlands. Just switch on your TV and hey presto you have BBC1 and 2, German channels, French channels, American and sometimes even Dutch.
Try to get some funding from your employer to learn a language and you are met with the standard responses: "You don't need it", "How will this help productivity?". There is only one way we in the UK will learn a second language and that is to make it compulsory. For example, my colleagues in Germany would not be able to do their job if they could not speak English, even if they are only dealing with German customers.
I remain unconvinced that we will all need to learn Mandarin. I remember many years ago being told that we should learn Japanese as they were so good at 'reverse engineering' products and they would dominate the world markets. I also remember being told a similar thing about Latin America. I then went to university and was told by a lecturer that we would have to learn Russian as that would be the next 'big thing'. Now it is Mandarin. I would like to think I am wrong, but experience tells me otherwise.
Stephen Macfarlane MIET, Edinburgh
High-def TV tips
One of your '10 questions to ask before buying an HDTV' (Gadget Speak, Vol 3 #5) was whether it has a digital tuner and can handle high-definition terrestrial signals. With current proposals for broadcasting terrestrial HDTV in the UK based on the use of DVB-T2, a standard which has yet to be finalised, the answer is likely to be no.
This raises an important question - with a significant proportion of the population set to receive only a cut-down version of Freeview (three out of the six multiplexes) from their local relay after digital switchover, and the new Freesat service from the BBC and ITV expected to launch imminently, is it time to put behind us the notion that a terrestrial tuner is the 'standard' way to receive TV and should therefore be built into every set? With the choices between free-to-air and subscription, satellite and terrestrial, and the emergence of IPTV, shouldn't the receiver and the display now be treated as separate devices?
Ben Kemp MIET, Cumbria
You point out that standard-definition television can look awful on a high-definition display and suggest looking for models that can upscale the signal. UK PAL-625 standard signals have 576 displayed lines, so upscaling these to 1,080 lines will involve either significant interpolation, or (more likely) the simple discarding of 18 lines at both top and bottom to allow simple and high-quality 2:1 upscaling.
High-specification PC monitors often have 1,200 lines. Why can't the same standard be used for HDTV displays? Not only would this allow for clear and complete display of PAL-625 material, but 1,080-line material could be displayed along with status and other information.
Tim Forcer MIET, Southampton
Safety at sea
Phil Burge's report on how technology can prevent critical equipment from failing at sea ('Catastrophe in the balance', Vol 3 #4) took me back to an earlier life when I earned my crust bobbing around the oceans of the world as an engineer on various types of merchant ships.
Condition monitoring, as it is currently understood, was virtually unknown. 'Dismantling of machinery' was carried out to a schedule issued by the classification society in order that its surveyors could certify that the vessel remained 'in class' and therefore seaworthy. Opening up plant and equipment not only allowed wear rates to be assessed but, more importantly, to be returned to design standards in a planned rather than reactive manner. A further, often overlooked, benefit was that it gave the ship's engine room staff an in-depth knowledge of the construction of all essential equipment and systems and also the ability to repair them.
Attitudes to automation varied from company to company. I well remember one chief engineer telling me that he had applied to attend a training course on machinery control systems to be met by a response from the chief superintendent engineer of "you don't need to do that, let me know if you find any automatic controls on our ships. I'll have them taken out".
At a time when we have become used to blindly following instructions and information provided by black boxes, it is perhaps difficult to appreciate the record of reliability that was achieved by the correct design of plant and machinery and having appropriately trained and competent operating staff who were in turn backed-up by sound management and monitoring systems. Very few British registry vessels were lost due to machinery or systems failure. The continual drive to reduce manning levels, find lower-cost crews and reduce constructional standards has produced the inevitable results.
FP Hawke, Truro, Cornwall
Switching to teaching
The news story 'UK engineers urged to consider teaching' (Vol 3 #4) came as a surprise. I have been a qualified technology teacher for two years having successfully completed a PGCE. Prior to that I worked in industry for 20 years.
I am yet to find a full-time position as there are not enough vacancies. My background is irrelevant to schools and colleges when choosing candidates. The people usually appointed are fresh out of university with little practical experience. The amount of rejections is turning me away from the education sector.
Paul Curnick, by email
The media tells me that there is a shortage of qualified teachers in maths and physics and a shortage of pupils who want to make a career in science and engineering. I suggest that the IET, in collaboration with the government and industry, set up a scheme where engineering and science professionals act as classroom assistants for two hours a week to support maths/physics teaching, using the classroom assistant role set up for primary schools.
Companies releasing engineering talent may need some encouragement, and there will need to be classroom training for people more used to workstations. The upside is that pupils will have access to people who know the subject, the importance of it, and how to do interesting stuff with it.