One of the reasons why people are so scared of science these days is that technology has become more inexplicable, and somehow more “black box”. Fifty years ago, with a bit of practise and a good grounding in school science, you could fix your car and understand how your radio works. You wouldn’t stand a chance these days, but it was not ever thus: Japanese War Tubas, only a few decades ago, were the very pinnacle of modern technology, and your best bet for locating an enemy in the distance, or in the dark (that’s Hirohito on the right).
At first these devices just look like hearing trumpets, with a pretty obvious mechanism of action.
But there’s actually much more to them than that. Like other pre-radar acoustic location devices, they cunningly exploit and hack the acoustic location hardware you already have in your own ears and brain.
We can locate objects with our ears, using the difference in volume between our left and right ear, but more important is the time delay between the sound hitting one ear and then hitting the other. This is possible because sound travels so incredibly slowly, only 330 metres (or 1000 feet) per second. Thinking out loud, that means sound travels one foot in one millisecond, so if your ears are about six inches apart, the sound coming from your right will hit your right ear about half a millisecond before it hits your left ear. A millisecond is quite a long time: in a piece of music, for example, you can spot notes that are only a few milliseconds out as being in the wrong place.
So these devices amplify the incoming sounds, but also, because the collection horns are placed much wider apart than your ears are (on either side of your head) they also increase the difference in arrival time between each ear. This, as well as the amplified volume, would help you to become more accurate in locating far off objects.
My guess is it would probably take a while for your auditory cortex to re-callibrate and get used to the wider gap, and the greater difference in arrival times, so you’d need plenty of practise.
Consequently, the designers had to make their apparatus as stylish as possible.
Nicely spotted by the excellent Athanasius Kircher Society. I have Grade 5 Tuba and I still put it on my CV.
Jodrell said,
May 24, 2006 at 4:56 pm
There’s a whole load more photos of different acoustic radar devices here, which I remember Bruce Sterling discovering a couple of years back.
John A said,
May 24, 2006 at 6:25 pm
Actually the calculation of the maximum interaural time difference (ITD) is a little more complex since the sound has to travel around the head. But you’re pretty close the maximum ITD experienced by a human is around 0.65ms.
I am sorry that you are unimpressed with the temporal resolution of the auditory system – it tries really hard. The brainstem pathway involved in ITD sensitivity has some very exciting specialisations designed to encode the temporal structure of sound with exquisite precision and fidelity. For example, it has some of the largest synapses in the brain, dense myelination and some rather sexy potassium channels.
All this means that the smallest ITD that we can discern is as low as 15 microseconds. Which is tiny – you try that with light flashes, taps on the skin etc.
“My guess is it would probably take a while for your auditory cortex to re-callibrate and get used to the wider gap”
Just to be extra pedantic – I’m not sure that it is the auditory cortex that is important in plasticity with respect to ITDs – my money’s on the inferior colliculus.
Frank said,
May 24, 2006 at 6:31 pm
This reminds me of a similar device called a hyperscope, which as the name suggests uses mirrors to increase the distance between your eyes. I guess it would increase your depth perception at distance, but it had funny side effects at small distances – objects became smaller as they got closer!
Words cannot describe the curious effects of the pseudoscope, which switches the left/right feed in your eyes.
Terry Pope not only works with these, he sells them on his website:
www.phantascope.co.uk
though for £350 you might be tempted to make your own.
Big_Les said,
May 24, 2006 at 6:54 pm
The Imperial War Museum have a steel (WW2 I think) and a wooden one (WW1) in storage. The steel jobbies come sort of flat-pack/self-assembly!
Ben Goldacre said,
May 24, 2006 at 6:53 pm
mmmm yup, my friend john the psychologist says:
People can accommodate to different inter*occular* distances pretty
quickly, see also prism adaptation, but I’ve not thought about auditary. Counterintuitively, audio is harder to figure than video. Interocular distance is only one part of auditary spatial perception, there’s the head-related transfer function (ie frequency dependent attenuation) and the shape of the pinna. Sorry, you probably know all this. There are some very convincing 3d audio sound cards based just on headphones and a simulated HRTF, but I never mucked around with changing the separation. If it worked (and I guess it would, quite quickly), Dolby and co probably know all about it. There was also some company that would put tiny mics in your own ears and do you a bespoke system based on your own ears. Money for old rope once you got the code working, but imagine the audiophile wankpoints.
as somebody who enjoys mucking about with synthesisers i’ve always wondered whether there is a psychoacoustic explanation for the attraction of the filter sweep: that thing where the sound starts muffled and then becomes more open (you get it in fatboy slim builds and “weeeoooowwww” sounds on synthesisers). maybe the change in attenuation of frequencies is an extreme version of the change in sonic landscape when you walk out of a cave, or an extreme version of the influence of the pinna. tum ti tum.
profnick said,
May 24, 2006 at 7:17 pm
Don’t think you’re american Ben?
www.gcse.com/english/practice.htm
Ben Goldacre said,
May 24, 2006 at 7:27 pm
i love how picky everyone around here is. les: are you telling me i can buy one from the imperial war museum, ikea style? and more importantly, have you gone and played with them?
Frank said,
May 24, 2006 at 7:56 pm
I hate the “filter sweep” so beloved of dance djs. It’s so hackneyed. It’s the dance equivalent of a key change in the final chorus of a pop song.
raygirvan said,
May 25, 2006 at 12:16 am
Jodrell: acoustic radar devices
In similar vein, check out this old blog post, mainly about Listening Ears.
FredM said,
May 25, 2006 at 8:14 am
There are a number of examples and variations of this phenomenon. The whispering gallery at St Paul’s is probably the most famous in the UK – a whisper can be heard over 40 metres away. The Great Ball Court at Chichen Itza in Mexico beats this by a factor of >3. A similar effect can also be heard in St Peter’s, Rome (a whisper in Michelangelo’s dome can be heard in the church). I’ve come across a few smaller scale examples in other buildings.
Incidentally, Jules Verne used the whispering gallery effect as part of a plot device in “Journey to the Centre of the Earth”.
keyrawn said,
May 25, 2006 at 9:57 am
The Germans frustrated users of sound locators by adjusting the engines in multiengined bombers so that they did not run synchronously. You could always tell a German bomber from one of ours by the variying engine sound. In the kids section of the Science Museum they had a pair of dshes at each end with patforms for a child to stand on at each focus. It was possible to have whispered conversations across the crowded noisy room.
Rage on Omnipotent » Blog Archive » Japanese war tubas said,
May 25, 2006 at 8:47 pm
[…] You have to love an article called Japanese War Tubas. But I don’t think it is bad science. Surely its excellent science, just superseded? […]
BlogBites. like sound bites. but without the sound. said,
May 26, 2006 at 1:58 am
[…] Japanese War Tubas, only a few decades ago, were the very pinnacle of modern technology, and your best bet for locating an enemy in the distance, or in the dark (that’s Hirohito on the right). badscience » Japanese War Tubas […]
BorisTheChemist said,
May 26, 2006 at 10:55 am
Wow! Something that combines my two passions Science and Brass Playing.
I’m off to invent the british war trombone.
PS I have grade 8 trombone and still put it on my CV!
BobP said,
May 26, 2006 at 6:55 pm
The guy in the last pic looks like Tommy Cooper to me …
John A said,
May 27, 2006 at 10:49 am
Not sure what your question is. If you are asking about participating in synesthesia research there are a few researchers out there. e.g.
www.psychol.ucl.ac.uk/jamie.ward/synaesthesia.htm
If you are asking how non-synesthetic people can experience synesthesia, LSD often does the trick.
Robert Carnegie said,
May 27, 2006 at 10:13 pm
I once saw a TV programme, I think Magnus Pyke may have been involved, where a volunteer spent a week wearing an appliance which inverted the visual image for each eye. By then they were able to navigate and I think they had some trouble once it was taken off.
I hope it wasn’t lasting… I don’t remember if the story is known to be true that a video game designer crashed his real-life car into a tree because he expected it to disappear when the car touched it, or something like that.
I think it was fairly well attested, not unreasonably, that astronauts even after a short flight find themselves placing objects in mid-air and expecting them to stay put or to move gently in the direction they are pushed.
raygirvan said,
May 27, 2006 at 11:34 pm
astronauts even after a short flight find themselves placing objects in mid-air and expecting them to stay put or to move gently in the direction they are pushed.
I recall this idea being explored in one of Asimov’s stories, The Singing Bell, where a suspect for a murder on the Moon misjudged the throwing of a precious object (hence casting doubt on his alibi to have been on Earth).
foggy said,
May 28, 2006 at 6:34 pm
And I have Grade 7 French Horn.
Eat that, Mr Fuck Off Academic Ninja!
Delster said,
May 29, 2006 at 7:56 am
f:lux,
if you think this is geeky just hang around a while 🙂
f:lux said,
May 31, 2006 at 4:26 pm
But Delster, I’m entirely with you. I was thinking of the bagpipe more as an offensive weapon – we may joke, but I was convinced they were developed for use in battle to frighten the enemy (though this could be a lingering trace of old ‘Carry On up the Khyber” that I haven’t yet managed to eliminate from my system). Bit like the battery of giant Japanese tubas in the wonderful photo at the outset. In a battle between bagpipes and war tubas, which would win in the scary stakes?
Am I lowering the tone or something? Thanks Robert, but Girl Genius looks like a blond Harry Potter with boobs to me. So no.
HarryR said,
July 14, 2006 at 7:35 pm
I believe that owls have one ear canal longer than the other to help them pinpoint rustling voles. And, you know, other rustling prey.
OT: I remember the Dungeness listening ears – I went there birdwatching once. The lakes have Great Crested Newt and Medicinal Leech, which are both real rarities.
Dean Morrison said,
July 15, 2006 at 9:08 am
Perhaps we could use thes war tubas to finally sort out whether those expensive hi-fi cables work??
dormouse said,
July 16, 2006 at 9:16 pm
Going way OT:
Re: Girl Genius
Part of the ludicrously talented output of the great Phil Foglio whom I had the enormouse fortune to meet in Seattle many years ago. Finding his house was doddle – usually American streets are long and the numbers seem to go on forever. As I slowly walked along checking numbers I realised there was one house with a huge pair of cartoon cat eyes on the garage door…
Buck Godot, Zap Gun for Hire is also worth a look if you enjoy silly SF.
wotsisnameinlondon said,
July 22, 2006 at 10:27 pm
38 Comments so far and not a single mention of the infamous Mukkinese Battle Horn. Spine Millington must be turning in his grave.
sciencefan said,
August 15, 2006 at 8:13 pm
Am I showing my age by mentioning the attempt to use of very low frequency sound as a weapon during WW I ? I think it was organ pipes attached to air pumps – a sort of reverse War Tuba – and designed to cause severe discomfort to the enemy (churning up vital organs etc). Not that I was there at the time, I hasten to add; I read about it many years ago.
I seem to remember that the first trial revealed that the designer had failed to appreciate that the sound would be propagated in all directions! I can’t remember now how they managed to turn the thing off.
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The Lost Art of Detecting Incoming Aircraft Using Your Ears | Art said,
February 18, 2012 at 11:11 am
[…] Retronaut, Bad Science, and Andrew […]
Twentieth Century Science: Acoustic Mirrors and War Tubas « Because I Can said,
March 27, 2012 at 7:08 pm
[…] of updating my links so I could post it this week I discovered io9 had scooped me a month ago. Bad Science has an interesting post as well. Like this:LikeBe the first to like this […]