Dumb audio question. worried my audio will kill someone, any help

M

mrpink89

I was reading an article about bit rates and depths ( http://www.head-fi.org/t/415361/24bit-vs-16bit-the-myth-exploded)

and there was a quote that i was confused about so i came on here to ask
quote:

"If this is the case with CD, what about 24bit Hi-Rez. If we were to use the full dynamic range of 24bit and a listener had the equipment to reproduce it all, there is a fair chance, depending on age and general health, that the listener would die instantly. The most fit would probably just go into coma for a few weeks and wake up totally deaf"

My rates are at 48k/24

I know it's probably dumb but do i have to tweak my 24bit depth so it wont kill someone if they listen to it at a high volume? Do I have to mess with the full dynamic range so it doesn't kill people? if so how?
 
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mrpink89 said:
like I said I know the question might of sounded dumb but my brain was itching and it wouldn't leave me alone so I had to scratch (ask)
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That quote you were given is kind of dumb, imo. And you're being a goofball, but I think I understand what the quote meant.

It's basically saying if the lowest audible sound is played (and is 000000000000000000000001 volume in the bit stream), then playing it 16 million times louder (at 111111111111111111111111 volume), it would kill you by the volume. I don't know if that math they gave is true, but the ONLY point is that you will never use the full dynamic range of 24bit sound.

[Edit: I think 24 bits means you can represent a swing of around 200db. That means at 0 dbA (the limit of what humans can hear), 24 bits can represent from 0 up to 200 dbA, which is essentially as loud as a bomb landing on you.]

The volume will only ever be as loud as the equipment can produce. Your 100W amplifier doesn't suddenly become a 160,000W amp by adding a bunch of bits to a digital stream, ready to cause a death-inducing shockwave.

Nevertheless, 48/24 is industry standard. So use it.


That gif was pretty appropriate.
 
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stef said:
That quote you were given is kind of dumb, imo.
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Neither the quote nor the article were dumb, they are correct!

You've essentially hit on the answer though, that the OP misunderstood the part: "If we were to use the full dynamic range of 24bit and a listener had the equipment to reproduce it all ...". This is a hypothetical to illustrate the point of the article but in reality "the equipment to reproduce it all" does not exist. So "no" mrpink, it's extremely unlikely you would kill anyone in a cinema. However, it is entirely likely that peaking at maximum levels (0dB) will be seriously uncomfortable or even painful to some.

The point of the article is that 24bit is ridiculous as a distribution format and even 16bit is excessive. However, for the acquisition of audio 24bit is useful because it allows for plenty of headroom.

stef said:
[Edit: I think 24 bits means you can represent a swing of around 200db. That means at 0 dbA (the limit of what humans can hear), 24 bits can represent from 0 up to 200 dbA, which is essentially as loud as a bomb landing on you.]
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24bit allows 144dB of dynamic range. To actually hear that dynamic range you would need a system capable of 144dB dynamic range above the noise floor, which typically is about 50dB. So this hypothetical system would need to produce peaks at 194dB .... which is about 4 times higher than the 180dB figure said to cause death!

To put this in some sort of context: If the peak level of a 24bit system were the same volume as a truck driving past at 50mph from 10ft away, then the quietest sound the system would be capable of (-144dB) would roughly be the volume created by two hydrogen atoms colliding!

G
 
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The [mantis shrimp] snaps a specialized claw shut to create a cavitation bubble that generates acoustic pressures of up to 80 kPa at a distance of 4 cm from the claw. As it extends out from the claw, the bubble reaches speeds of 60 miles per hour (97 km/h) and releases a sound reaching 218 decibels. The pressure is strong enough to kill small fish
 
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In the United States, movie theaters have to operate under federal Occupational Health and Safety regulations (OSHA), which include sound limits. You as a filmmaker/copyright owner can't be held responsible if someone outside your control cranks up the volume in your creative work and injures someone, unless you specifically (and negligently) give instructions to do so. Nightclubs, music festivals, etc., routinely violate sound limit laws and frequently get sued for injuries and annoyance. Search online for: loud music lawsuit and loud music lawsuit osha. The EU also has its own version of OSHA.
 
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Okay, here's how you potentially kill someone with sound...

https://www.youtube.com/watch?v=a-njcAia6nY


Oh, here's a sound system that could actually kill you...


The Large European Acoustic Facility (LEAF)


https://www.youtube.com/watch?v=mtQcQWsMjx0

The Large European Acoustic Facility is used to perform acoustic noise tests on spacecrafts and their external payloads to assure that no damage will occur during the rocket launch. The facility simulates realistic spectral noise pressure levels comparable of those generated by the launcher engines and air flow passing along the launcher faring. The automatic control system offers a great variety of selectable noise levels, spectral shapes and test durations to meet user requirements also from outside space industry.


Oh, and just for fun....

MI0001709384.jpg


In the late 1970's when The Ramones had hit it big they went to the sound company that was doing the sound for their tour and asked "What is the thresh hold of pain?" "120 decibels." "Okay, we want to reproduce that at the back of any room we play." They were only playing big clubs and small theaters, but they were frigging LOUD!!!



1972

Deep Purple held the record and were recognized by The Guinness Book of World Records as the "globe's loudest band" when in a concert at the London Rainbow Theatre their sound reached 117 dB. Three of their audience members were rendered unconscious.

1976

The Who were listed as the "record holder", at 126 dB, measured at a distance of 32 meters from the speakers at a concert at The Valley in London on 31 May 1976.

1996

Pioneering English House/Electronica band Leftfield became known for the volume of its live shows on the tour to support their debut album Leftism. In June 1996, while the group was playing at Brixton Academy, the sound system caused dust and plaster to fall from the roof. Sound volume was 137 dB.

2009

On July 15, 2009, in Ottawa, Canada, the band Kiss achieved a SPL of 136 dB measured during their live performance (not the sound check). After noise complaints from neighbors in the area, the band was forced to turn the volume down.

2011

On December 13, 2011 when the Foo Fighters played in New Zealand, their concert was recorded on the GeoNet seismograph for the duration of their 2½ hour set (although the weight of the fans dancing was a major contributing factor to this). This is not the only instance of the Foo Fighters playing at extreme volumes; their performance at Tennent's Vital 2012 in Northern Ireland drew noise complaints from up to twelve miles away.
 
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AudioPostExpert said:
24bit allows 144dB of dynamic range.
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I understand what you said but I couldn't figure out exactly how to do the math on that, although I'm probably the only person interested... could you elaborate on the math? I realize the decibel scale is logarithmic, but messed up when figuring out 2^24 converted to dB. How is that done? The insane number of different units used in sound confuses me.... dB, dBA, SPL, LUFS, etc.... (Okay, I kind of have an idea of what most of them represent, but not precisely.) I figured dBA was the appropriate unit to use when discussing dynamic range.
 
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