I think it will also help to understand what you wish to achieve. Do you just want to be able to test/review continental equipment without having to replace the plug in which case a Schuko socket strip with a 13A plug fitted would be sufficient? If you are trying to compare the effects of UK and continental mains supplies there are a lot of differences to consider including the use of lower rated three phase supplies to the continental buildings.

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.

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?

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

And, although I am not from a hi fi background, (I'm the sort for whom you could make a simpler piano by eliminating every other key as they sound the same ...  musicians usually wince at this, but its true)  I am very much on your side - don't assume there will be  no perceived effect until you have measured everything well outside the 'normal' range.

Your comments about phase are interesting - do you mean phase of harmonics relative to fundamental (i.e, zero-crossing and peak moving), or just suck instead of blow by reversing the polarity of the coil of the speaker - which I'd expect to be discernible if the waveform is assymetric - which an N-wave event like an explosion usually is (- not too surprising - you can generate over pressure to many atmospheres at the origin of the explosion, but you cannot go below vacuum on the ensuing rarefaction. By the time you get far away, the pressures are less damaging, but the asymmetry is preserved. I can well imagine an upside down bang that starts with a suck instead of a blow sounding wrong.)

M.

mapj1 said:

or just suck instead of blow by reversing the polarity of the coil of the speaker

Yes exactly that. I don't know whether it's still true, but it certainly always used to be received wisdom that this couldn't be detected. My mentor in audio design (someone with a tremendous reputation, and with a fantastic set of ears) discovered it by chance when he was demonstrating an audio system which one day sounded different to him, and he discovered that someone had indeed reversed both sets of loudspeaker connections by accident. So we got quite interested, and set up an A/B test which we tried on absolutely anyone that passed - audio engineer or not!

As you say, it's not actually that surprising that, e.g., the initial hit on a bass drum sounds different depending whether it's "pushing" or "sucking" - particularly as we know the ear is non-linear. So it surprised me how emphatic some enthusiasts got that we must have biased the test somehow...

I was more impressed when a few years later we borrowed some fantastic people at the old BBC research centre to give us a second opinion on one of our designs, and one of them (again, someone rather well known back in the day for a certain loudspeaker design) picked up a very slight phase shift, over only a small frequency band, between our system and the reference...took us ages to find that one. He couldn't tell it what it was, but he could pick it out as "different" every time. The BBC research centre guys were really great to work with (my memory may be wrong, but I don't think we paid them anything, they just helped because they were interested), probably the most unbiased people I ever met in the industry..

Cheers,

Andy

I have long said that one of the great ironies in life is that by the time that you can afford the best audio equipment, you can no longer hear the difference.

(Yes, I do appreciate that there are a few v. wealthy young people.)

Actually, it's surprising. Even though we all lose our high frequencies (at the very least), there's lots of other aspects of hearing - I suspect particularly special positioning - that, providing we don't actually go deaf in one or the other ear, we do keep, and it does make a huge difference. As well as playing music I listen to a lot of live acoustic music, and the recorded version hardly ever actually sounds the same even with my 64 year old (and battered with loud music and power tool) ears. But I recently visited my 80 year old brother, who has possibly the best audiophile sound system I've ever heard (and as you'll gather I've heard rather a lot), who played a solo violin recording and it was extraordinary. With my eyes closed it did genuinely sound like they were there in front of me. (Of course it was also fantastically recorded which was why he was playing it to me.)

The ears themselves might deteriorate, but the brain can even improve it's ability to process sound over time given practice. On a related issue, by accident I've found myself helping fellow musicians of my sort of age move from playing from sheet music to playing by ear in sessions, which involves really working the way the brain processes sound. It's shown - and I know form my own experience - that it's amazing what you can learn to do in terms of processing sound. Which I guess is why it was promoted recently that one good way of delaying dementia etc is to learn a musical instrument late in life (makes me feel justified for having picked up three new ones in the last few years!) 

P.S. Not that I'd ever advocate spending huge amounts of money on a home sound system unless (like my brother and the OP) it's the thing you enjoy doing. When I was in the industry, and people asked my advice on buying hifi, I'd generally advise to just spend enough until you find a system that doesn't actively annoy you. Personally I probably could have afforded a reasonably expensive sound system at home long ago but all my money went on musical instruments instead...

Andy Millar said:

.S. Not that I'd ever advocate spending huge amounts of money on a home sound system unless (like my brother and the OP) it's the thing you enjoy doing. When I was in the industry, and people asked my advice on buying hifi, I'd generally advise to just spend enough until you find a system that doesn't actively annoy you. Personally I probably could have afforded a reasonably expensive sound system at home long ago but all my money went on musical instruments instead...

So true. Most people can tell a really bad system, I can't listen to music on a mobile phone. When I couldn't really tell the difference between my Dual 505/NAD system and my flat mates Linn Sondek/Naim system (I'm dating myself here) however I stuck with the Dual (now replaced with a Denon system) and spent the money on my rally car.

Andy,

Super interesting! Thank you. I love the perspective the founder of your company had. It’s refreshing.

For the reason you describe so well, I also left HiFi forums many years ago. I don’t know of any other subject where people get so horrible so quickly. It’s also why I have tried to avoid “but can you hear a difference” here.

Perhaps privately, I’d be intrigued to know the company you worked for. I’ll then tell you who I write for!

Thanks again 

Paul

No great secret, it was on the recording side rather than the listening side, it was SSL (Solid State Logic). In the late 80s and early 90s I was one of the two lead analogue designers there. I left when that world went digital, not because I objected to digital but just because the opportunities for interesting new analogue design were obviously going to be very limited, and indeed 30 years later SSL are still producing analogue equipment incorporating my designs - as well as digital clones of my designs, which rather amuses me. Personally with all the opportunities that the digital world offers I wouldn't limit it by cloning analogue designs which were heavily limited by what we could achieve in the technology. But there you go, it's nice that people still like them. Anyway, I moved into the rail industry which being many years behind the times still needed analogue audio frequency design expertise!!!

So a lot of the perspective was that we were producing a recording tool, and its sound could not get in the way of the recording process, it had to be as transparent and faithful as we could make it. Although interestingly our only real rival was Neve, and Rupert Neve's products did have a very distinctive sound which he liked, and George Martin liked, but of course people who didn't like it didn't like it and were stuck with it. We sold a lot more desks than Neve did... 

Sadly the only desk that we designed that I'd really want to use for an absolutely top quality acoustic recording never went into production, because vanishingly few customers could have justified the cost (at 1990 prices £500,000+ against our normal system prices of £200-300,000). For that sort of recording you don't actually need all the features a desk of this size has, you might as well use something smaller which can be vastly cheaper for the same quality. But we learned a huge amount getting there. 

Cheers,

Andy

No great secret, it was on the recording side rather than the listening side, it was SSL (Solid State Logic). In the late 80s and early 90s I was one of the two lead analogue designers there. I left when that world went digital, not because I objected to digital but just because the opportunities for interesting new analogue design were obviously going to be very limited, and indeed 30 years later SSL are still producing analogue equipment incorporating my designs - as well as digital clones of my designs, which rather amuses me. Personally with all the opportunities that the digital world offers I wouldn't limit it by cloning analogue designs which were heavily limited by what we could achieve in the technology. But there you go, it's nice that people still like them. Anyway, I moved into the rail industry which being many years behind the times still needed analogue audio frequency design expertise!!!

So a lot of the perspective was that we were producing a recording tool, and its sound could not get in the way of the recording process, it had to be as transparent and faithful as we could make it. Although interestingly our only real rival was Neve, and Rupert Neve's products did have a very distinctive sound which he liked, and George Martin liked, but of course people who didn't like it didn't like it and were stuck with it. We sold a lot more desks than Neve did... 

Sadly the only desk that we designed that I'd really want to use for an absolutely top quality acoustic recording never went into production, because vanishingly few customers could have justified the cost (at 1990 prices £500,000+ against our normal system prices of £200-300,000). For that sort of recording you don't actually need all the features a desk of this size has, you might as well use something smaller which can be vastly cheaper for the same quality. But we learned a huge amount getting there. 

Cheers,

Andy

Andy Millar said:

I was more impressed when a few years later we borrowed some fantastic people at the old BBC research centre to give us a second opinion on one of our designs, and one of them (again, someone rather well known back in the day for a certain loudspeaker design) picked up a very slight phase shift

Andy – in the period you were mentioning I worked at the BBC on the periphery of loudspeaker design with the people at the Research Department you mention, along with others in Radio and Television Studios well known in the industry. It was a hugely enjoyable time (sadly no longer).The aim was to have loudspeakers that sounded like the original sound. One advantage was that we could listen to the live sound in the studio and compare it directly to the reproduced sound from the speakers. That seems to have been your aim at SSL, but as you mentioned, other companies took a different approach, producing a “characteristic sound”.

Off at a slight tangent, I love my cathode ray tube televisions because they are analogue - though of course the set-top boxes are not. We do have a modern television, but I find it a bit sparkly. It is difficult to put it into words, but I suspect that it has to do with contrast.

Chris Pearson said:

I find it a bit sparkly. It is difficult to put it into words, but I suspect that it has to do with contrast.

I had the same experience going from vinyl to CD, but overall I preferred CD.

Now, the quality of sound with surround system with relatively small speakers is brilliant, and good enough for most people at home - and I don't think I will return to analogue audio. It's great to reminisce and look at the old album covers. I've not thrown away my vinyl albums, and now my son is listening to some of them on his vinyl player ... and enjoying the artwork ... as part of the recent revival.

gkenyon said:

Now, the quality of sound with surround system with relatively small speakers is brilliant, and good enough for most people at home - and I don't think I will return to analogue audio.

Yes, it is amazing what small speakers can achieve. Then again, the ear drums are only about 1 cm in diameter or about the size of the tip of your index finger. (Slightly larger than a BS EN 61032:1998 finger tip.)

gkenyon said:

It's great to reminisce and look at the old album covers. I've not thrown away my vinyl albums, and now my son is listening to some of them on his vinyl player

Forget vinyl, what about your 78s?

Chris Pearson said:

what about your 78s?

I'm old enough to remember the setting on the turntable, but I never owned any of them. Not that I don't admire a wide variety of music, but the reality is people were burning their "radiograms" and grammophones in the 1970s when I was a toddler, and people were smashing the Bakelite '78s.

Not all of them - by the late 70s I was repairing the odd radiogram, well, valve swapping and doing basic 'wire off' and switch cleaner  type repairs anyway, when the shops would no longer repair them. Like the 1950s piano smashing contests, the radiogram destruction probably varied a bit. And there were some terrible designs out there. Rather like some folk look nostalgically at old houses and say 'they built them well back then' what they mean is they built the ones that are still here now, well, back then. The slum grade stuff has been bulldozed and rightly so.

Mike.

Andy Millar said:

Anyway, I moved into the rail industry

No way! The Railway's my day job! I joined BR as an Engineering Management Trainee (probably one of the best graduate training schemes ever) and remain. Small world.

I do have a 1920s HMV wind up gramophone (bought by my brother and sister for a couple of shillings in the 1950s) together with a pile of 78s in the bedroom...when you look at it with an engineering eye it's actually a very neat bit of technology. And really quite good for explaining how sound waves work

Re vinyl and CD, I found this most interesting in the early days of CD players, to me they sounded dreadful whereas I didn't mind the pops and scratches of vinyl, other people were much more irritated by the background noise of vinyl but didn't mind what I could hear in CD players. The problem with the early CD players was that, if you imagine them playing back a peak-to-peak triangle wave, each "step" in the A/D process was likely to be of a different height to the next one - say the average step height across the 65,535 steps is 1uV, then in practice one bit step might be 0.1uV and the next 1.9uV (to take it to extremes). The manufacturers worked hard to makes sure that each step always went upwards, but they weren't necessarily even. Which produces a very non-musical (non-harmonic) distortion. Vinyl does also typically have distortion too of course, but it's more likely to be harmonic. But there you go, again it was a case of things that annoy some people and not others. And, at least to my ears, got resolved in reasonably priced CD players by the end of the 1990s.

And then of course currently one of the biggest selling formats is the compact cassette which, pure audio wise, has to be one of the most appalling formats ever developed. (Although a very clever bit of technology for its time.) Just like I do have a much loved two-valve guitar amp behind me...

Re small speakers, what they can't do sadly is move enough air to project bass sounds at any distance. (OK, you can combine lots of small speakers, but that's really the same impact as having one big speaker.) Frustrating point at the moment as I've been playing quite a bit of bass guitar in otherwise acoustic bands recently, acoustically the only solution would be to move to double bass (which are both massive and really hard on the fingers for a very good reason) or to carry a bass amp. And even though I have about the smallest one it's possible to get (that's of any use) it's still a lump. It does feel like there are times when you just get hit by the laws of physics, but it would be great if somebody did come up with a cunning way of slowly moving lots of air without needing lots of weight / size! I'll keep hoping.

Contact made 

mapj1 said:

Not all of them - by the late 70s I was repairing the odd radiogram, well, valve swapping and doing basic 'wire off' and switch cleaner  type repairs anyway, when the shops would no longer repair them.

I did the same with televisions. They could be had for 10/-, which soon became 50p. The CRTs were faded so the curtains had to be shut, but with luck one lasted for 6 months.

mapj1 said:

Rather like some folk look nostalgically at old houses and say 'they built them well back then' what they mean is they built the ones that are still here now, well, back then. The slum grade stuff has been bulldozed and rightly so.

Most of my 120 y.o. house was built well, but it has become apparent that there was extensive refurbishment circa 1982. The real problem was lack of maintenance and ivy growing up the walls. At which point, young folk will ask, "What is maintenance?"