Following the talk in this thread http://forums.bit-tech.net/showthread.php?t=79346 in the name of science and electronics loving, I will subject myself to brown noise which Double_C informs me is between 10.5 to 16hz. The unit of measurement thanks to cpemma will be Fartz The setup: I thankyou... 'doc
I see three problems with what you're doing: 1. Speakers won't even hit anywhere near 16Hz. Kilohertz, yes. Hertz, no. Try using a subwoofer 2. You're going to need a really specialized subwoofer to hit 16Hz. My Klipsch Promedia 2.1s are quoted as going as low as 31Hz. The sub on this thing is pretty damn beefy for computer speakers. Unless you have the uber-expensive 5.1 Creatives, your sub isn't as big as mine. I doubt it'll hit below 30Hz. 3. Cartman already found the brown noise. If it's on South Park, it must be true!
Yer I know the speaker will have trouble :/ but wishfull thinking, I have got a huge sub somewhere, given to me by a neighbour... and: EDIT: I had it going through one speaker, I have put it through my 7.1 setup and I can still hear the wave at 23-24hz
typical.... just make sure you arnt wearing your best clothes.. though i doubt this will work at all...
I've seen something on speakers for this - IIRC instead of using a cone, they had a sheet... Sheet... geddit?
You need pretty powerful speakers to make you c**p yourself mate. There was a famous British ragga band (think they were called aswad or something) and the front row of the crowd would regularly fill their trousers because they had so many bass amps! I'd hate to be standing behind them
groan... Nothing yet but I'm off to bed, hmm should I leave it on in the night? 'doc EDIT: I haven't really contemplated the thought of this working, hate to imagine if it did...
Brown noise: power density decreases 6dB per octave with increasing frequency (P(f) = 1/f 2 ) over a frequency range which does not include DC. you guys are awful...
I know which site that is copied and pasted from, thats the wrong kind of brown noise, the name for the brown noise you are talking about comes from the fact it displays Brownian motion. 'doc
http://www.halfbakery.com/idea/Defecat-o-mat is the 'Doc dream. Though Kerri Ann's 'Noise showing a random walk behavior' seems to fit the bill as a result, or maybe 'Noise causing a random walk behavior' would be closer. The 'Throne mounting Butt-Kicker' sounds like a useful gadget for the frequently-constipated...
Hi all. I've just been off the toilet after trying m own experiments with brown noise. The MP3 on Brainiac's website is a 1 minute long perfect example of brown noise. After putting a scope on the line-out of my computer and playing the MP3 over and over again, I have seen that brown noise is two sine waves super-imposed on each other. The larger sine wave has a period of 20ms, giving a 50Hz frequency. The smaller sine wave has a period of 10ms, giving a 25Hz frequency. The ampltude of the smallet wave is less than the larger wave, but it is impossible to work out the ratio. I hope this helps, _C
holy crap, i thought it was a sick joke!!! there actually is a brown noise? someone has to post results.
OT: I can make myself burst into floods of tears with just a copy of sound forge and the chopper dx plugin, alas tests on my wife hav'nt worked, but I can repeat it over and over on myself, Don't get me wrong the sound is'nt high picthed its the choppiness of it that seems to make my eye's flood, wierd stuff indeed EDIT: I also have the same phones as you
There's been a rumor for over 20 years that Blue Oyster Cult actually had this happen at their concerts...sounds suspiciously similar to the Aswad story (although BOC was known for being one of the loudest bands in the world, some time back.) As mentioned above, though, you're going to be hard-pressed to find a commercially made speaker that will produce frequencies that low. Human hearing can detect frequencies from 20Hz-20kHz (20,000Hz.) And that's assuming that you've got perfect hearing (most people have hearing damage to some degree, and most hearing damage begins with the high frequencies.) In the Audio Engineering course I took in High School, my teacher did an experiment with Pink Noise to see how high of a frequency everyone could hear. Only two people could hear 18kHz, and I was one of them....it is not pleasant to listen to. It's like a needle driving into your brain or something, very uncomfortable. Most people can only hear up to around 14hHz, and dogs can hear somewhere in the range of 40kHz or some insanely high frequency like that. Bass frequencies travel differently though, and are very directional. That's why you actually feel them more than you actually hear them (think of pulling up next to a car with a loud subwoofer. You can feel it and it seems "loud", but most of the time you can't actually make out the individual notes.) More Useless Musical Trivia: Kate Bush (famous UK songstress) actually did work with the British military when they were testing theories on how to use audio frequencies in warfare. She actually wrote a song about it (I think it's called "The Project" or something like that.) The US military has actually used audio very effectively...They blasted Van Halen's "Panama" for a few days outside of Manuel Noriega's compound, over and over again at concert volume levels, until he finally surrendered. I don't know if something like that would make me crap my pants because of the volume, or because there's two hundred US Marines outside my house blasting Van Halen...
Not to be anal but... ...any regular speaker can produce 16Hz, but at a very reduced sound preasure level or SPL. The frequency response given by speaker manufacturers is usually (depending on the manufacturer) at the -3dB points, not the absolute limitations of the speakers. To play 16Hz with any apreciable SPL I'd guess you would need a 15" to 18" woofer, but I think even these size of speakers have a natural roll off at about 25Hz. I once saw a 24" woofer sitting on the shelf at an electronics surplus shop... it had a lot of dust on it. If you're interested in looking into this "phenomenon" further, a specially built bandpass speaker box will double your SPL at the tuned frequency. As for the human hearing range... (please note all frequencies given are generalities and vary from person to person). The accepted range is from 20Hz to 20kHz, as has been said, but I've read that 30Hz to 16kHz is more realistic. However, frequecies below this can still be felt eventhough not heard, all the way down to about 5 to 10Hz. Just a note... notes lower than about 60Hz are considered nondirectional, meaning you can still hear it but can't perceive what direction the sound is coming from. But at such a low frequencies as 5 or 10Hz, the only thing perceived is a change in preassure at best. I have heard that the american military was doing research into using subsonic sound as an immobilizer as such. If the subsonic frequencies are played with enough SPL it disrupts the central nervous system and causes loss of bodily functions which could account for the "Brown Noise".
You might find the 50Hz wave is for effect, when they played it over the TV their was no clearly audiable noise, as they carried on with the program, that may be their so people think they are not listening to silence. 'doc
Would the 50Hz signal by any chance have anything to do with current ripple from mains AC (also 50Hz) which just isn't filtered out properly? I know whatever did the recording/playback used DC but there would still be a (minor amplitude) 50Hz ripple in the voltage. Not an expert. Just extrapolated from first principles.
