Use of Schuko sockets in a UK home only for a HiFi system

Paul Soor said:

… who generally believe, if it can’t be measured, it’s not real. I find their forum interesting but I don’t subscribe to “measurement or nothing”.

Interesting. I used to design rather high end sound equipment (we're talking hundreds of thousands of pound rather than thousands of pounds), and the principle held by the founder of the company was rather the other way around "if it can be heard, it can be measured". We found that a very important principle in equipment design - if somebody could reliably hear a difference (and we got really good at blind testing) we'd go to huge efforts to find what that difference actually meant in signal terms (and we're talking months or years of research here). So that we could then consider that in all future designs. Now we were lucky that we had the funds to do that, most audio companies are run on a shoestring and can't, but also that culture was vital to ensure that conclusions weren't jumped to. 

So usual engineering principle - don't assume an engineering change can't have any impact, determine if it does have an impact and then find out why! Right down to root cause. Sadly too few audio companies seem to do the last step...but as said, both steps (can it be heard, and why) can be really really difficult.

What I've found interesting on audio forums in the past (I try to stay out of these discussions these days, bad for my blood pressure) is that these things work both ways, there are people who take it as a matter of deep belief and faith that certain things can't be heard. The ear-brain interface is pretty amazing at detecting differences, although the brain can be pretty rubbish at interpreting those differences. The biggest examples we found were that most people can tell the difference between two pieces of music with a 0.1dB level difference (although in our tests they didn't perceive it as a level difference), and that most people can hear absolute phase (at least on percussion type sounds). Both of which we found by accident, and at the times were, for different reasons, a pain in the bottom, we'd rather not have found them! I've had people rant and rave at me on forums when I've mentioned these, and try to find all sorts of bizarre explanations - much more complicated than the simple fact that they could be heard - which is interesting. I've always responded with "don't rant at me, go and try it". Of course there's also the question of whether either actually matter (which again is why I stay off such forums now), since you don't know which was "right" in the first place...ok, maybe there's a case for absolute phase in some cases. (They mattered to us because we were doing A-B comparisons and it was important that nothing unintended got in the way of these.)

I'll admit that one of the several reasons I left the audio industry was due to frustration with some of the uninformed discussions with clients - yes some of the capacitors in our systems are purple, no we don't consider that purple capacitors sound worse than blue capacitors, yes there is a make and model of capacitor that sounds worse than another make and model of capacitor but it's for these other technical reasons, not because it's purple...

These days I find musical instrument construction (as a hobby interest) much more interesting...but has many of the same issues, for example it's fascinating getting involved in the discussion of different varnishes on stringed instruments. (And again, some extremely well informed and researched, and some not...)

Sorry I was trying to avoid going off on my hobby horse but failed to stop myself! I'll shut up now.

Thanks,

Andy

Paul Soor said:

I have a question about using Schuko sockets in a UK domestic home.

OK, BS 7671 would permit the use of a Shuko, provided it has shutters - I understand without departure. Shuko with shutters are definitely available.

The main problem is the Plugs and Sockets (Safety) Regulations. Whilst it's permissible to supply Shuko socket-outlets in the UK, these cannot (according to the legislation) be supplied for 'domestic and similar' use. 'Domestic and similar' has a wide interpretation, but would include supplying the socket-outlet for the purposes of plugging in an appliance with a suitable plug rated up to 3 kW (230 V rating plate) or 3.1 kW (240 V rating plate) - called "pluggable Type A" equipment in a number of product standards.

So, if you buy it yourself (and don't tell anyone what it's for), an electrician could fit it, provided:

 - It has a declaration of conformity with a standard of another CENELEC country that is based on IEC standards; AND

 - it has shutters on the live ports; AND

 - It is going on a suitably rated circuit (usually 16 A or 20 A) according to the manufacturers' instructions (as others have stated, not ring final circuits usually), and protected by a 30 mA RCD/RCBO for TN-C-S or TN-S supplies.

Or, you can fit it yourself (with the appropriate certification for BS 7671 of course), provided you are competent to do so, and it meets the above requirements.

Fujimoto may be doing clever things electronically, but the fact is that the tones which were presented to the ear(s) were from 125 Hz to 8 kHz - see fig. 2.

The bone vibrators stimulate the cochlear nerve in the usual way. Ever tried listening to a tuning fork by biting the foot?

OK, so if your ears cannot perceive very high frequencies, how can you perceive them at all?

The non-linear mixing of modulated ultrasound is a fairly standard way of casting sound directionally - the 'sound' is only re-created at the point of detection.

This chap has done it at the party trick level to 'throw' music with 40KHz transducers.

https://www.youtube.com/watch?v=TQOabMOMGoE

the ultrasound  power levels are higher than I would want to be bathed in but hey-ho.

(google the 'voice of god' weapon for a possible use in warfare, to either instruct some poeple but not others, or to make folk think they are hearing instructions when there is no obvious source,  but there is no public domain evidence to suggest that the idea has left the lab, but in principle it should work.)

Then there is also quite a bit of evidence for sensing ultrasound without inter-modulation though bone vibrations stimulating other nerves not normally associated with hearing.

https://www.sciencedirect.com/science/article/abs/pii/S0378595505000481

This leads to sensations, rather than actually 'hearing' but may be part of the 'feel' of music.

Mike.

OK, so if your ears cannot perceive very high frequencies, how can you perceive them at all?

I guess you can perceive the effect of something even if you can't directly perceive the thing itself. If there were two or more high but different frequencies, I might be able to hear the lower frequency interactions (beat?) as peaks and troughs interfere sometimes constructively sometimes destructively. Sort of Fourier analysis in reverse.

   - Andy.

OK, so if your ears cannot perceive very high frequencies, how can you perceive them at all?

One has to be careful - it has been shown that (some) humans are responsive to effects that are quite a long way outside the traditional audio range ( perhaps 10Hz to 20KHz and more like 300 -3000Hz for mobile phone "dalek quality" speech - think mobile 'phone..) 

Correctly instrumented measurements on audio kit need to include looking for effects up to perhaps 50KHz plus that might be attended by apparently imperceptible  roll-off and small phase errors in band that would generally not be noticed.

Also some people 'feel' ultrasound effects, even when they do not report hearing them.

a reference

I'm firmly in the 'if it can be heard it can be measured' camp by the way, but I would say that for a satisfactory measurement one needs a degree of rigour and precision often lacking,

Mike.

I’m going to digress a little..

In terms of hearing, music is much more than frequencies and frequency response. We know that because people who are lacking in frequency extremes (lots of us) still make and experience amazing music. For example the sense of rhythm has nothing to do with frequencies. It’s a feeling you either get or don’t. There is not right or wrong.

I guess you are saying, are the improvement measurable? There is a forum called Audio Science Review…

https://www.audiosciencereview.com/forum/index.php?reviews/

… who generally believe, if it can’t be measured, it’s not real. I find their forum interesting but I don’t subscribe to “measurement or nothing”.

So, having said that, where frequencies are being addressed, they tend to be very high frequencies.

Did I kind of answer your question?

Paul Soor said:

If you consider HiFi equipment as extremely high precision data retrieval instruments utilising electricity, one could brainstorm many opportunities to corrupt data retrieval, conversion (digital and analog), amplification and transmission to the speakers. And never have we had so many EMI, EFI and EMC challenges as we do these days.

And the ears and the auditory pathways turn the sound waves back into electricity.

However, you haven't answered my questions.

Let's start again with the frequencies which might be affected. Low or high please?

I’m going to use “tame Sparks” in my review!

Thanks