
The World’s Loudest Sound (2014) - wallflower
https://kottke.org/14/10/the-worlds-loudest-sound
======
AndrewKemendo
In the 90s early 00s I got really into car audio, specifically Sound Pressure
Level (SPL) competitions. The goal is to make your car into a resonance
chamber for a single note and see how high you can get it.

Most competitors just buy a lot of batteries, amps and drivers and call it a
day. However being a broke high school student I had to figure out how to win
on a budget, so I went deep on the physics. If you go deep enough you start to
really get into interesting work on the physics of acoustics and harmonics.

One of the things I learned about was the testing and sound suppression work
that went into the Saturn V. A genius acoustical engineer named John Hilliard
[1] was a main driving force for designing the systems that would protect the
Saturn V from it's own reflected sound waves. Not only that but also creating
long range signaling systems for the US Military.

In order to do the testing he needed to do, he had to build a driver that
could simulate the SPL of the Saturn V. That meant figuring out a way to go
past the 183 dB limit for sine wave in normal atmospheric conditions. You
can't actually do that with the standard inductive-coil driver, because the
wave becomes "clipped" and effectively turns into a square wave, which will
cause the induction coil to burn up very quickly. So they needed to create a
new driver that was based on air passage.

Anyway, fascinating engineering work. Unfortunately it wasn't anything I could
use in my car but I learned a lot about sound.

[1]
[https://en.wikipedia.org/wiki/John_Kenneth_Hilliard](https://en.wikipedia.org/wiki/John_Kenneth_Hilliard)

~~~
staticautomatic
For a time I was very into home/pro speakers that produced tons of bass. I
recall reading once about a Kenwood speaker about the size of a fridge that,
when driven by a measly 25 watts or so, could rattle the windows of a house
across the street. I have no idea if it was real and can't seem to find where
I originally read it, but I remember being really taken with the idea.

~~~
AndrewKemendo
See the trick to really "loud" bass is finding resonance between the
environment and the driver FS (Free Air Resonance). Enclosure size isn't
really directly relevant.

The trick is to try and couple all of it, so that there is a resonant point in
the environment which matches the resonant point of the Enclosure and the
enclosure matches the FS of the driver. If you line up all of these then you
can get the whole world to shake on a tiny amount of power.

It's possible that the Kenwood driver just accidentally did that for someone's
house and it all lined up. There were tons of old wives tales like this.

Wattage is misleading too. If all your frequencies are dorked up and you have
standing waves and cancelling waves all over the place, then you have a
sonically chaotic environment no matter what the power you are pumping is.

~~~
erikpukinskis
Are you familiar with any of the theories that prehistoric megalithic
structures were cut and moved with sound waves? There are lots of 20, 50, even
100 ton solid stone blocks around that no one really knows how they were cut
or moved about.

~~~
AndrewKemendo
No I don't recall ever reading about that, though it sounds interesting - if
implausible. Do you have any reference materials?

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m-i-l
Don't forget: "Disaster Area was a plutonium rock band from the Gagrakacka
Mind Zones and was generally regarded as not only the loudest rock band in the
Galaxy, but also as being the loudest noise of any kind at all. Regular
concert goers judged that the best sound balance was usually to be heard from
within large concrete bunkers some thirty-seven miles away from the stage,
whilst the musicians themselves played their instruments by remote control
from within a heavily insulated spaceship which stayed in orbit around the
planet - or more frequently around a completely different planet."[0]

On a more serious note, I did see a band once that I later found out were
infamous for their loud gigs. While most in the audience had gone prepared
with earplugs, I had none, and for their "finale" (which incidentally didn't
feature the band actually on stage presumably because it had become too loud
even for them) I had to go outside of the main room and keep my hands over my
ears. Even now I sometimes worry that night might have permanently damaged my
hearing. The stupid things some people do when they are younger.

[0]
[https://hitchhikers.fandom.com/wiki/Disaster_Area](https://hitchhikers.fandom.com/wiki/Disaster_Area)

~~~
cyberferret
As a former guitarist in a loud rock band, I concur. I didn't use hearing
protection in my teenage years and 20's, and now (in my 50's) I suffer from
tinnitus.

My hearing is actually OK, because at some point, I decided to start using
hearing protection (and still do now when I roadie for my son's metal band),
but the tinnitus I think could have easily been averted by just not exposing
myself to those sorts of volumes at close range when I was young. The damage
is permanent and not worth the few seconds of 'coolness' to stand at the front
of the stage at a hideously loud live gig.

(NB: My best friend at high school was deaf, and a favourite party trick of
his at concerts was to turn his hearing aids off, then stick his head into the
cone of any exposed speakers at the front/side of the stage for a minute, then
back off and watch other kids come up and try it. In hindsight, that probably
permanently damaged the hearing of MANY foolish kids who tried it out of peer
pressure or wanting to outdo him, and not something to be proud of upon
retrospection.)

~~~
Itsdijital
When I was younger we used to go to these warehouse parties in the industrial
zones of the city. Nobody was anywhere around after 8 so it was pretty much a
free for all.

Anyway they would set up these massive speakers and absolutely blast the
music. There was one guy who would occasionally show up, tripping _hard_ on
god knows what, and dance with his head pretty much buried in the cone of an
18" driver. I mean like non-stop for 5 or so hours.

As we got to know more of the regulars we learned that he was deaf, and by
doing that he could feel the music and all it's intricacies running through
his body. Always made me smile after learning that. Never got to meet him
though, because he was always, well, way off in space so to speak.

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sjclemmy
I was camping in west Wales (UK) in summer and there were some really odd
sounds coming in off the sea. The sounds were not audibly ‘loud’; you could
here them but they sounded like they were a long way off. What was strange was
that they ‘hurt’ the eardrum and could be felt in the chest. I speculated that
it was big guns or something. But I’ve no idea really. Does anyone know what
this could be? The internet is particularly unhelpful.

~~~
tyingq
Pembrey Sands Air Weapons Range maybe?
[http://www.aeroresource.co.uk/operational-reports/pembrey-
sa...](http://www.aeroresource.co.uk/operational-reports/pembrey-sands-air-
weapons-range/)

~~~
sjclemmy
I don’t think so. We were near Tywyn. So Pembrey is probably a bit far south.

~~~
tyingq
There's this also: [https://www.milfordmarina.com/cardigan-bay-danger-area-
mod-a...](https://www.milfordmarina.com/cardigan-bay-danger-area-mod-
aberporth/)

Looks like they have a pretty broad "danger area".

~~~
sjclemmy
That’s the range. So definitely a test of some sort. Possibly the MIRACH
system as detailed here
[https://aberporth.qinetiq.com/faq/index.aspx](https://aberporth.qinetiq.com/faq/index.aspx)

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nodesocket
Somewhat related, the huge explosion in China (Tianjin) as captured on video.
Not sure how loud that explosion was, but it looked apocalyptic. In some of
the angles you can see the shock wave.

[https://m.youtube.com/watch?v=hUtrkfLKyFE](https://m.youtube.com/watch?v=hUtrkfLKyFE)

~~~
runarb
Video from the PEPCON disaster also show quit the shock wave:
[https://www.youtube.com/watch?v=cPVpzjxRjPk](https://www.youtube.com/watch?v=cPVpzjxRjPk)

~~~
spookthesunset
It's kind of funny that they made sure the explosion sound was heard when the
explosion happened and not when the person filming it actually heard it.

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gooseyard
I'd like to recommend Simon Winchester's "Krakatoa The Day the World Exploded,
August 27, 1883" to anyone interested in learning more about the Krakatoa
eruption. It's quite a story.

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missingPieces
The author draws a comparison between Krakatoa and the Saturn V, one being a
singular energetic event, and the other being a sustained projection of
energy.

On the one hand, you have a shockwave of pressure differential travelling out
from a central point of release, and on the other you have sustained
stimulation due to a high-volume controlled dump of potential energy.

That the consistent oscillations of the Saturn V can melt concrete and set
fire to grass at a distance by disturbing the air and conveying thermal energy
through kinetic collisions alone doesn't really seem like a useful correlation
to an impulse event that reverberates across the entire atmosphere.

If I had my druthers, though, I'd wager that the gravity waves of a
supermassive black hole merger, as detected by LIGO, would likely make for a
better analogue to the Krakatoa event.

The Saturn V engines are loud, but the nature of the concept is probably
better modeled by the fact that you can boil water with a high-end kitchen
blender or similar food processing appliance.

~~~
TheOtherHobbes
You - and everyone on Earth - should probably be thankful Krakatoa wasn't
trying to play rock music.

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praptak
There's a volume threshold above which the pressure wave in the air reaches
the amplitude where the lows fall below the vacuum, right? But what happens if
you give the air particles energy level above that threshold?

~~~
TylerE
You can continue to get louder, as only the negative part of the waveform is
clipped.

~~~
mikeash
Incidentally, this is why rocket launches sound crackly. It’s not overdriving
the microphone, but rather the air itself.

~~~
p1necone
This is the coolest fact I've heard all week, thanks.

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golergka
That makes me wonder, why didn't this eruption leave a more of a trail in
popular culture of the time? Shouldn't it have been the THING everybody would
talk about non-stop for a few years afterwards?

~~~
cbkeller
Well, for one thing there was no telecommunication, so most people may not
have known it was a global event.. people (outside of the range where it was
entirely ear-shattering) may have just thought "huh, I guess they're firing
the guns down at the battery" and only months later found out it was some
faraway volcano

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ohiovr
That’s twice as loud as Tsar bomba which sent a wave around the world twice.
Or 5 times louder than car stereos in my neighborhood!

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LiamPa
The video of the sound wave? from the volcano moving the clouds is impressive!

~~~
cyberferret
Also note the ground around the point of explosion being turned over by the
shock wave as it moves out. That video was a great illustration of how the
pressure wave moves out in all directions as an expanding ball - it is too
easy to misinterpret the wave as a flat circle moving outwards from a point,
rather than a sphere.

