"WhiteNoise" - EVP upsurge?

[Ashles]

Popular culture is a reflection of common belief, not a source.

This isn't true. The consistency of alien abduction stories has only happened since the media and popular programming has shown so many "greys" and gone into so much detail about abduction experiences.

Peopls aren't born inherently believing that aliens look like greys - for most people it is learned from the media. They then incorporate this into their belief system about about aliens.

Most alien believers talk about the captured alien bodies at Roswell. This was only an invention of the eighties. For over 30 years this never existed as a myth. Then (I think) the story was published in a book or film and all of a sudden it became widely believed 'fact'.

Who ever believed that LA gangbangers follow you and shoot you if you flash them to let them know they are driving without lights? No-one, until the legend was started.

 

[geni]

This isn't true. The consistency of alien abduction stories has only happened since the media and popular programming has shown so many "greys" and gone into so much detail about abduction experiences.

Peopls aren't born inherently believing that aliens look like greys - for most people it is learned from the media. They then incorporate this into their belief system about about aliens.

As an extension of this the technolgy seen in UFOs has changed from big leavers to LCDs over the years

 

[Dr Adequate]

I disagree. Popular culture is a reflection of common belief, not a source.

The X-Files is amongst the sources most commonly cited by American university students (see F. Wheen, How Mumbo-Jumbo Conquered The World).

 

[Azrael 5]

Well the people over at supernatual world forums seem to like it:

http://www.thesupernaturalworld.co.uk/forum/index.php?showtopic=5125&hl=

EVP seems to have been popular for a while. This is probably because recording devices are cheap and there is a good chance you will got something. Simular to orbs in apeal (ie you can get your own).

If only I wasnt banned form even seeing that forum,I could tear their silly theories apart! Actually..no I wouldnt as one post and Id be banned anyway.Geni perhaps you might....?
Wonder if the people at ghostsuk are debating this...oh,Im banned there as well...lol

 

[geni]

If only I wasnt banned form even seeing that forum,I could tear their silly theories apart! Actually..no I wouldnt as one post and Id be banned anyway.Geni perhaps you might....?

Not much in that particular thread. Anyway starburn still hangs around there so I think the forum is covered.

 

[Azrael 5]

Got a bizarre paranoid raving from webmaster of supernaturalworld recently! Ill PM it to you...

 

[jj]

Re: Re: evp on morning TV

Well, you know, colored (not white, please) noise can create an impression of indistinct voices, especially if it has a couple of spectral peaks near formant frequencies.

There's nothing new, surprising, or even moderately supernatural about that.

White noise is a constant, unchanging "hiss", so whatever they're talking about, it's not white noise.

White noise has equal energy per frequency.

Colored noise does not. Pink noise, the usual kind discussed, drops at 3dB/octave, and has equal energy per octave instead of per frequency. Taking pink noise and adding just a tiny bit of irregularity gets you a "sometimes speech-like experience".

Making such stuff synthetically is childs' play, read up on "LPC Coding" in Jayant and Noll's "Waveform Coding" book.

 

[Ashles]

That's interesting jj.

In fact in this article about White Noise it actually says:

Because white noise contains all frequencies, it is frequently used to mask other sounds. If you are in a hotel and voices from the room next-door are leaking into your room, you might turn on a fan to drown out the voices. The fan produces a good approximation of white noise. Why does that work? Why does white noise drown out voices?

White noise actually drowns out voices - so not a great way for spirits to communicate.

 

[jmercer]

That's interesting jj.

In fact in this article about White Noise it actually says:


White noise actually drowns out voices - so not a great way for spirits to communicate.

Oh, I dunno. Considering the apparent urgent information people are getting via EVP from the great beyond, I'd say that white noise is a highly appropriate medium for that particular set of messages.

In fact, there are a couple of earthly voices I'd like to use white noise on, even as I write this...

 

[BPScooter]

As I recall, and as jj pointed out, white noise contains equal energy at all frequencies. Natural sounds contain very specific energies at very specific frequencies, and that's how our ears evolved, to be more sensitive to the important sounds (a footfall behind us in the forest, a rattlesnake, on and on). So white noise isn't used much except maybe by acousticians trying to "tune" a room, but really not even then. Too much wasted energy going into the creation of a sound that is not perceptually important. Maybe the occupational hazard people would use it, to make sure your ears aren't getting fried by something you aren't really reacting to.

But "pink" noise is better, because it follows the perceptual curve of what our ears pick up on. So I think that's how it works, it puts more "oomph" into the bands of frequencies we are most aware of. Isn't that what "A" weighting and "C" weighting are all about on a decibel meter? I think so.

As far as energy goes, it takes more to produce a loud low-frequency sound. That's why speakers have woofers and tweeter, partly, and why it takes a good big amp to run the home theaters and car stereos.

Sorry if I messed up, but I've been involved in music and audio for some time and this is what I remembered.

 

[jj]

That's interesting jj.

In fact in this article about White Noise it actually says:


White noise actually drowns out voices - so not a great way for spirits to communicate.

Well, that's not entirely accurate, but it's not too far off. Strictly speaking, equal-energy noise in the first 20 critical bands would do the most to muck up voices, give or take.

It would do so by having the "feel" of a voice you can't make out, too.

It's tempting to do a "message" up in matlab, something like "there is no such thing as EVP"

 

[jj]

But "pink" noise is better, because it follows the perceptual curve of what our ears pick up on.


More or less, but certainly not exactly so, above 1kHz or so, and definitely not below that in any sense. On the other hand, pink noise is certainly a much better match to how our ears work than white noise, even if your analogy is off quite a bit.


So I think that's how it works, it puts more "oomph" into the bands of frequencies we are most aware of. Isn't that what "A" weighting and "C" weighting are all about on a decibel meter? I think so.


A, B, and C Message Weighting are, well, some attempts to do something with perception, but there are some not-so-great assumptions that come along for the ride. 'A' is roughly relating things to speech, and 'C' to more broadband signals, but neither is a really good measure of loudness (that's the internal representation in your head), although it does, of course, measure intensity (sound pressure level) reasonably well, given knowledge of the weighting curves.


As far as energy goes, it takes more to produce a loud low-frequency sound. That's why speakers have woofers and tweeter, partly, and why it takes a good big amp to run the home theaters and car stereos.


You're confusing the energy in the signal with what it takes to make a signal of a given energy, perhaps. Volume Velocity * f^2 is proportional to Sound Pressure for a source smaller than a wavelength, again give or take. That means that to create a 20Hz signal you have to move 16x as much air as you do for an 80Hz signal. With some speakers this can take different amounts of energy, but for a single driver that's tuned right, not a great deal different energy. A lot more cone motion at 20Hz, though.

Woofers and tweeters are necessary because of the need for volume velocity at low frequencies, and because woofer cone materials aren't nearly rigid or light enough at high frequencies.

The various drivers can be different in efficiency, the reason isn't as simple as what you say, though.


Sorry if I messed up, but I've been involved in music and audio for some time and this is what I remembered.

You're not far off.

If you have one of those old keyboards that you could sing into, have it take channel vocoder paramters from your voice, and then add white noise to the voder input, you could really make some cool EVP, couldn't you? I remember, many, many years ago, playing with such a device at an AES. I think it was, um, oh, I forget who made it.

 

[BPScooter]

Thanks, jj, I was off-the-cuff, there. I could tell you knew what you were talking about! My memories come from a class 20 yrs. ago and that's a long time!

The thing I'm most interested in is the perceptual part, the psychoacoustics. Again, I'm not up on it as much as many others, but here's something I thought was cool, about how we are able to perceive meaning in relatively undifferentiated sorts of sounds--

http://macserver.haskins.yale.edu/haskins/MISC/SWS/SWS.html

 

[jj]

Thanks, jj, I was off-the-cuff, there. I could tell you knew what you were talking about! My memories come from a class 20 yrs. ago and that's a long time!

The thing I'm most interested in is the perceptual part, the psychoacoustics. Again, I'm not up on it as much as many others, but here's something I thought was cool, about how we are able to perceive meaning in relatively undifferentiated sorts of sounds--

http://macserver.haskins.yale.edu/haskins/MISC/SWS/SWS.html

Well, that's a very nice resource given the subject. Thanks.

Anyone got an old keyboard/synth with the channel vocoder on it? That would make for some great demos of EVP

 

[joobie]

i'm just waiting for hollywood to make a movie about the coffee pot ghost.

edit - darn, looks like that page is gone. shucks.

 

[Azrael 5]

i'm just waiting for hollywood to make a movie about the coffee pot ghost.

edit - darn, looks like that page is gone. shucks.

No it hasnt.