Acoustic Measurements of BRC?

[dragonfly Jafe]

Has anyone ever taken any acoustic measurements of the background sound of Black Rock City at night?

[Badger]

Yep.

[Bob]

What you say!!

[Mister Jellyfish Mister]

Has anyone ever taken any acoustic measurements of the background sound of Black Rock City at night?

Right on Jafe. Still into the subharmonic thing? I would love to know gama ray and LF measurements just for fun. Good luck!

[Isotopia]

Data available upon request.

[dragonfly Jafe]

Has anyone ever taken any acoustic measurements of the background sound of Black Rock City at night?

Right on Jafe. Still into the subharmonic thing? I would love to know gama ray and LF measurements just for fun. Good luck!

Oohhh! I like the Subharmonic name (not technically correct, but cool sounding none-the-less...) - "Welcome to Dr. Gavrieaux's House of SubHarmonic Happiness"

I need an infrasonic detector to ensure I don't accidentally dose the city with unwanted stimulus. It turns out to be basically off-the-shelf hardware (used in elephant communication studies), so I was wondering if anyone had ever brought anything like this to BRC (given all the drums, generators, sound art, etc)

[robotland]

I've had a subharmonica in a drawer somewhere for YEARS- never learned to play it. I can, however, operate a pornograph......

[dragonfly Jafe]

I can, however, operate a pornograph......

But do you know how to operate one manually?

[theCryptofishist]

I can, however, operate a pornograph......

But do you know how to operate one manually?

Carefull. YOu can give yourself a nasty shock that way.

[geekster]

This seems a little scary ...


Infrasound: Very low-frequency sound that can travel long distances and easily penetrate most buildings and vehicles. Long-wavelength sound creates biophysical effects: nausea, loss of bowels, disorientation, vomiting, internal-organ damage, or death may occur. By 1972 an infrasound generator had been built in France. When activated it made the people in range sick for hours.



From:

http://www.harpers.org/WhenKillingJustWontDo.html

[dragonfly Jafe]

Sound in the 7-12 hz range is known to have this effect, even if the exposure is brief (less than 10 minutes). Walt Disney slowed down a recording of a 60hz power hum 1/5x from a soldiering iron using recording gear (this made it 12 hz) - less than 1 minute of this made his employees sick for hours. On the other hand, Nikoli Tesla used these frequencies in short bursts (30sec - 1 minute) in his "Rejuvenator", a device that perportedly invigorated ones nervous system and made one feel refreshed. I suspect in reality the effect was just ones adrenals kicking in. Mark Twain (samuel clemens) reportedly stayed on the device for too long with embarrasing results. The army calls this "the brown sound"

But I want to avoid these frequencies (for obvious reasons) and instead focus on the 16hz - 20hz range, which is actually the bottom of our musical octave, and the larger pipe organs create these sounds. The ocean surf typically has alot of 16hz energy also. So I am not proposing anything really radical (or dangerous).

The trick is to ensure that lower frequencies are not accidentally created...(say in a windstorm)

[Ranger Genius]

"the brown sound"

I thought that was just the guys from South Park. I tried to make the noise with my recorder, but it wouldn't work.

[dragonfly Jafe]

"the brown sound"

I thought that was just the guys from South Park. I tried to make the noise with my recorder, but it wouldn't work.

creating the signal is the easy part. Turning it into acoustic energy is the hard part. Very few commercially available speakers can produce meaningful amounts of sound in this region. Even the biggest conventional subwoofers do not do well. Also, trying to do it indoors creates more problems (the room interacts with the speaker). So unless you live in a very large house (like a concert hall) you probably could not listen to it no matter what you did. And if you did create it, your windows would suffer!

Outdoors on a flat plain is the best place for this stuff...

By recorder do you mean a flute-like object or a reel-to-reel recorder?

[Ranger Genius]

I mean a little plastic flute-thing we all had to learn to play in the fourth grade. Didn't you?

[dragonfly Jafe]

I though that was what you meant. Blow as you may on one of those plastic thingies, you won't be making any infrasound....(at least not that comes from the plastic thingie!)

[Mister Jellyfish Mister]

I though that was what you meant. Blow as you may on one of those plastic thingies, you won't be making any infrasound....(at least not that comes from the plastic thingie!)

Hi Jafe. I acquired a didgeridoo today and you can get some pretty low resonance out of it, but are limited by the length and resonance of the pipe. It occurs to me that it would be an amazing stripper pole if it was vibrated by a blower.

What if we build something people could blow in thse same way with lips a-flutter-ing but attach the end of the cheap PVC pipe to a diaphram of sorts. Think of a subharmonic speaker driver facing the playa. Stretch a big piece of latex rubber accross a ring. Play with it to get the average simathetic half-octave resonance right, and you have a powerless, interactive, subharmonic device right there on the playa! Your thoughts?

[Killbuck]

I've been listening with interest... a new sonic death weapon?

It would be devious to point it at Center Camp during the fashion show... adjust it just so, switch it on and see 400 people unleash their bowels all at once. Devious.

However, have you considered the possibility that it may attract wildlife into the city? Pumas, voles, ardvarks, dogs and cats, wandering in?

[Mister Jellyfish Mister]

I've been listening with interest... a new sonic death weapon?

It would be devious to point it at Center Camp during the fashion show... adjust it just so, switch it on and see 400 people unleash their bowels all at once. Devious.

However, have you considered the possibility that it may attract wildlife into the city? Pumas, voles, ardvarks, dogs and cats, wandering in?

I knew you would claim this weapon for the people. Therefore I have addressed this over on our camp thread:
viewtopic.php?p=142315#142315

[geekster]

I've been listening with interest... a new sonic death weapon?

It would be devious to point it at Center Camp during the fashion show... adjust it just so, switch it on and see 400 people unleash their bowels all at once. Devious.

No need. You have just described the pottys just across the street from Pinky's.

[dragonfly Jafe]

I've been listening with interest... a new sonic death weapon?

The possibilities are endless...as is resistance!

http://www.sempre.org.uk/list-archives/ ... 00406.html

[geekster]

BORG9 -- Smashing punks since 2005!

[Malochango]

Our focused beam acoustic transducers will create loads of havoc, er "fun" on the playa. But don't worry we're only looking for Rangers.

[Isotopia]

But don't worry we're only looking for Rangers.

Careful what you pray for.

[dragonfly Jafe]

Our focused beam acoustic transducers will create loads of havoc, er "fun" on the playa. But don't worry we're only looking for Rangers.

Of course, the intensity is greatest where the sound is produced (and it is very hard to direct), so you will be having the most "fun" yourselves.

Be sure to clean up.

[Malochango]

oh really . . . ?

Looking forward to having a great time this year.

I love all you peoplez!

[TheJudge]

Doesn't anyone ever watch "Mythbusters" on the Discovery channel? They did an episode about the "brown note" The answer is that it does not exist.

[dragonfly Jafe]

Hi Jafe. I acquired a didgeridoo today and you can get some pretty low resonance out of it, but are limited by the length and resonance of the pipe. It occurs to me that it would be an amazing stripper pole if it was vibrated by a blower.

What if we build something people could blow in thse same way with lips a-flutter-ing but attach the end of the cheap PVC pipe to a diaphram of sorts. Think of a subharmonic speaker driver facing the playa. Stretch a big piece of latex rubber accross a ring. Play with it to get the average simathetic half-octave resonance right, and you have a powerless, interactive, subharmonic device right there on the playa! Your thoughts?

For this to work, the "subharmonic" driver would have to be tuned to a low frequency (say 16 hz). Trying to excite a tuned system with a frequency that is much above (>2f) the resonance frequency is not very efficient. Further, to make significant sound levels, the driver would have to have to be making significant excursions (at least 5-10mm) - this would require a large energy source (probably not feasible with human lungs). Elephants for sure...

You could, however, make a long tuned pipe (aka didgeridoo) that a single person could excite (think those long horns from the Alps...)

You could also make a long stripper tube (out of 4" PVC say), and make a reed at the bottom that is powered by a blower (or blow across the top like a bottle), that would cause a resonant tone.

Another idea I saw somewhere was to take a long rope, attach a resonant diaphragm to one end and secure the other to a strong stake. When the wind blows, you stand so that the rope is perpendicular to the wind and pull it tight. The wind rushing over the string causes it to vibrate, and the vibrations are amplified by the resonant diaphragm. The tension on the rope determines the "note". Some obvious safety issues to sort out, but an interesting concept!

[TheJudge]

I think we're talking much lower. 5-20 Hz.

Here's more info:
http://www.meyersound.com.au/brownnote.shtm

[robotland]

You only Hz. the one you love.