When researching cool concrete loudspeaker designs the other day, I ran across one that stood out enough from the other by the simple fact that it is loud enough to kill people.
The facility was designed by and for the European Space Agency to test if equipment like space ship parts or satellites will withstand the acoustic stresses of a rocket launch.
I assume that most people who have been present during a rocket launch were knocked of their feet by the sheer obscenity of sound pressure produced in the event, even when standing several kilometers from the launch pad. Now if you were strapped to such rocket, you would be subjected to much higher sound pressure and that is exactly what happens to a satellite that sits in the payload bay, or a piece of equipment to add on to the international space station. Anything shot into space usually costs a lot of money and long before the countdown reaches 3 the engineers would like to have some level of confidence if the equipment will withstand that kind of noise.
That is why most space agencies operate acoustic testing facilities and the largest of its kind is the one we are talking about here.
In Loudspeaker design, one usually is confined by Hoffmann´s Iron Law:
Bass Extension
Loudness
Small Size
The law says that of those attributes you can chose any two, but never all three.
Now there are people who go to the very extreme of this trade off: Meet the Large European Acoustic Facility (LEAF)
Bass Extension: That that is usually found in the payload bay during a space shuttle launch.
Loudness: whack you around and eventually kill you.
Small Size: Large enough to sound like that.
Now while this might be a great setup to listen to Mahler´s "Symphony of a Thousand", it is of course not intended for music at all, but rather for spectral noise similar to that present when stuff blows up.
The technical specifications are very impressive indeed. The decibel rating goes up to 155dB which is actually quite loud, but certainly not off the chart that the good people at MakeItLouder keep.
What we can expect at 155dB are definitely a ruptured eardrum, difficulty breathing, overwhelming body compression down to the core, nausea and vomiting, a cooling of the body by up to 10 degC. We would also have a hard time seeing, would generally feel whacked around a lot, will never recover hearing and will die if exposed for any significant amount of time.
155dB is louder than being on the inside of a rock concert stadium speaker, it is also nearing the noise level of being on the inside of a jet engine during take off.
Interestingly enough, while this may be loud, it is certainly not as loud as it gets. The loudest car stereo ever built was 171 dB loud, it employed 80 drivers and needed 32 batteries to produce 100´000 Watts. This is about four times louder than the LEAF.
Also disturbingly loud is the launch of a Saturn Rocket at 220dB, as loud as a hand grenade or a sonic boom but lasting much longer.
By the way, there are also less apparent candidates to make a lot of noise, a toy balloon popping, perhaps (154dB) the noise level a blue whale produces (163dB) or the inside of a normal car cylinder at a modest 9:1 compression rate (216dB), diesel engines are twice as loud. (226dB)
And the obvious noise makers? Volcanos get incredibly noisy with the Tambora in Indonesia reaching 320dB in its 1815 eruption, the Tunguska Meteor (left image) reached 302dB in Siberia several orders of magnitude louder than the biggest atomic bomb ever detonated (285dB)
And what about the other side? What is the lowest noise level still detectable by well instrumented humans? During the cold war submarines have evolved their eaves dropping ability to detect noise levels as low as -80dB. This is the noise a shrimp makes 100m away while chewing its food. Incidentally it is exactly 400´000´0000´0000´000´000´000´000´000´000´000´000´000 less powerful than that Indonesian volcano. Let´s hear it for the logarithmic scale to help us keep things manageable.
As to where we are on the tradeoff against the Hoffman´s iron law of loudspeaker design with our SoundSommelier line of loudspeakers?
Bass extension: That which is needed to express most "real" musical instruments.
Loudness: Enough to make "normal" people want to turn it down just a bit in normal listening rooms.
Size: Whatever it takes. (It does not take much)
With a clever Quarter Wave design, we can push the envelope a little bit and keep things small with great WAF. Add great sound and natural clean bass and you have yourself a highly enjoyable setup. How loud? Well Louder than a chewing shrimp and quieter than the Tambora.