sound and recording

[shadow of a d]

Is it possible for consumer grade recording devices to record sounds outside of the human hearing range, but be audible upon playback? In other words, is it possible for recording devices to alter frequencies in any way?

[Ryan_m_b]

Welcome to PF! In response to your question yes of course it's possible, shifting the frequency is simple. Why do you ask?

[shadow of a d]

I mean without the aid of software. I'm trying to write an article in response to claims of "EVP" being infrasound or ultrasound. I realise that is you change the speed of the playback, it would allow you to hear the sounds, but i wondered if the device itself (analog or digital) altered it in any way.

[JaredJames]

Do you mean on their own?

You could certainly record something outside of our hearing range, but you would then need to use computer software (with a digital recorder) to alter it so you could hear it.

I'm curious why you came to scepticism and debunking for such a question (although I've got a good feeling why)?

EDIT: Answer noted.

[JaredJames]

EVP is the brain trying to make sense of random sounds. There's really no more to it (I'll add the disclaimer "as far as we're aware").

All the talk of 'infrasound' and 'ultrasound' is just people trying to use flashy words to describe the above and make it sound paranormal.

[shadow of a d]

I agree, and have mentioned that, but I'm attempting to tackle the other angles that proponents have put forth.

[JaredJames]

I agree, and have mentioned that, but I'm attempting to tackle the other angles that proponents have put forth.

There's really no other angles, just attempts to circumvent explanations in ever more grasping ways.

OK, so let's go one step further and look at the cause. What they are claiming is that something emits ultrasound and that the recorder picks it up - ok, I'll buy that for now - and then during playback without alteration, they are able to hear it - this is where my acceptance drops off.

Perhaps a poor quality device may be subject to slight distortion during recording/playback, but that's something you want to avoid when recording these things. The last thing you want is poor equipment giving false results - invalidating anything you collect.

The key point for you, would be the above. That equipment that doesn't reproduce the source sound, as close to the original as possible (without distortion), is useless and invalidates results. If it picks up ultrasound, it must reproduce it as ultrasound. If it doesn't, it is skewing your results and invalidating them. You can certainly alter it on a computer to try and work with it, but a device doing it 'accidentally' is not acceptable for data collection.

[shadow of a d]

Awesome, thank you.

[AlephZero]

You could certainly record something outside of our hearing range, but you would then need to use computer software (with a digital recorder) to alter it so you could hear it.

You don't need computer software and digital technology to do this. Radios using only analog electroncs are easy enough to design, and it doesn't matter where the input signal comes from. It could be any sort of transducer that converts something into a high frequecny electrical signal, instead of a radio transmitter.

"Bat detectors" work by pitch shifting ultrasound into the human audio range using the same principles.

[JaredJames]

You don't need computer software and digital technology to do this.
You could certainly record something outside of our hearing range, but you would then need to use computer software (with a digital recorder) to alter it so you could hear it.

I never said you did and I even included a caveat to show I was referring only to digital recorders.

I did so as most modern tech uses digital only so it seemed most applicable to me.

[christopherV]

to the op,

this is information on ultra high frequency sounds and patents around them.

here is a patent for a silent sound spread spectrum.

http://www.google.com/patents?hl=en&lr=&vid=USPAT5159703&id=sU4hAAAAEBAJ&oi=fnd&dq=Silent+Subliminal+Presentation+System&printsec=abstract#v=onepage&q&f=false

also


Flanagan GP. Patent #3393279 “Nervous System Excitation Device” USPTO granted 7/16/68.
Puharich HK and Lawrence JL. Patent #3629521 “Hearing systems” USPTO granted 12/21/71.
Malech RG. Patent #3951134 “Apparatus and method for remotely monitoring and altering brain waves” USPTO granted 4/20/76.
Stocklin PL. Patent #4858612 “Hearing device” USPTO granted 8/22/89.
Brunkan WB. Patent #4877027 “Hearing system” USPTO granted 10/31/89.
Thijs VMJ. Application #WO1992NL0000216 “Hearing Aid Based on Microwaves” World Intellectual Property Organization Filed 1992-11-26, Published 1993-06-10.
Mardirossian A. Patent #6011991 “Communication system and method including brain wave analysis and/or use of brain activity” USPTO granted 1/4/00.
O'Loughlin, James P. and Loree, Diana L. Patent #6470214 "Method and device for implementing the radio frequency hearing effect" USPTO granted 22-OCT-2002.


hopefully this will get you pointed in a good direction on ultra high frequency sounds.