hypersonic sound? HSS

[casper]

Has anyone heard of such a thing? HSS Wikipedia


I know this is not really studio recording related. I am trying to figure out if such a thing were in use, can it be measured with say an SPL meter? What would a typical quiet room read SPL wise, using a C weighting?


The potential to misuse such a thing is huge. There are also hand held units. link


I can see in the near future the guys on the side of the road advertising point this thing at you and bam you hear the advert in your head as well as seeing the sign. The potential for misuse is huge!


If this is not an appropriate forum to discuss this then can someone point me in the right direction? I am doing some research into how to detect when such a thing is being used. Let's just say it can be super loud or could be super soft. If it was quiet enough you may think you were thinking these things yourself .


Any help is greatly appreciated.

[AfaraWayland]

Yes, the discovery channel has had a "future weapons," segment that details some of this technology.

http://www.atcsd.com/site/content/view/27/41/

For reference, the quietest studios will only measure an SPL of around 20dB using a "C" weighting.

And yes, one could theoretically measure the SPL of these devices if the measurement device could in fact pick-up the audible frequency sent, in the limited area it was being sent to...

http://www.atcsd.com/pdf/HSS-Technol...ckgrounder.pdf

Seen above in the HSS pdf, what it is, is a ultrasonic frequency transducer (of sorts)...and according to them, the frequencies that are projected interact with air molecules, which intern are "down-sampled" or down-converted through that interaction with the air to a frequency which is audible to us humans. From one product pdf, a range from 250-20K Hz.

http://www.atcsd.com/pdf/Product-She...dSaber-400.pdf

Obviously, products like this are be coming popular with the government (military) and (local).

LRAD systems are already being implemented on the battlefield. As to being able to measure an LRAD system, they say in the topmost link, measure 90dB SPL directly behind the unit @ 1kHz, and 151dB for example at the target.

I don't know about you, but, even with hearing protection, the only thing I would be thinking about when facing an active LRAD system would be gettting aaawwwwaaaaayyyy from it fast.

By the way, hearing voices, that aren't your own is clinically known as:

Schizophrenia

[zildjohn01]

what i wonder about is whether the process can be reversed...

hypersonic microphone? the ultimate for close-micing...

just a thought

[casper]

Yeah we are just "hearing voices" twilight zone music goes here..

There is a transducer that can be worn around the neck which lets a person uttter words to himself and then in turn is transmited over a radio if this is what maybe someone is thinking by reversing this process.

I was in a quiet room at home in a house and measured 71 DB spl C weighted. No fans running no TV on no computer etc..just me and my wife in the room not talking yelling etc... The room read 62 DB the night before with about 5 people in there TVs going etc.. I had some spikes up to 68 DB but would not register a new peak high. The spikes seemed to be at regular intervals and were very short duration. The Isralis (mispelled to keep the google bots from finding this) used something called "the scream" recently according to accounts on the internet which may or may not be relaible. The device "pulsed" every 10 seconds or so. I am only trying to figure out if I am in the presence of such a device. No I don't hear "voices" people do seem to be able to read my mind on a regular basis however . I am completly rational and have read over the criteria for schizoprenia, sorry does not apply here.What I have heard on 1 or 2 occaisions in the past sounded like my Boss said "good morning" out on a loud shop floor, turned around and he was no where to be found. The guy who happened to be next to me heard the same thing. In this example makes me think the Sheriffs dept. a couple of buildings over was the culprit here not schizoprenia. Of course if a person complains of such things then one will be referred to a pyschatrist, unless of course we can prove that there is something going on then, I think proof is not very far off . I also had a couple of times when I was sitting at the computer and had a name pop in my head only to see a news article just 5 minutes later pop up on Yahoo with the guys name being the person who wrote the article. The guys name was no voice. It was just like I get this Joe Blow Joe Blow stuck in my head and then bam there goes Joe Blow's news article. It is kind of like when you get a song that plays over and over in your head...which I think most normal people have had this happen to them. Just making the point this is how subtle this thing was. This is but one of many examples. Obviously will be hard to tell what is truly your own thought and what may be being beamed at you if this was the case. The device listed above is supposed to be real noisy. There are a couple of others that are supposed to be much much cleaner/clearer. The latter happened in my home, in another state. I have a feeling I am being harrassed. Too long to type here.

I am going to find another meter and hopefullly be able to dial in any frequencies I may be emiting and or is being shot at me and then go from there. I suspect it is me that is emiting and not another source due to the SPL meter as far fetched as it may sound. Haha all the web sites out there covering this stuff all say uber high RF freqs and remote tracking etc.. I don't think so. I did not have much chance to do some real good A-B comparisons with the SPL meter. I may also try to rig up an array to measure infrasonic and or ultrasonic sound. I have done some simple recordings and have what appears to be 90-100 hz tone when I am in the room. The further I move away from the room the lower the tone goes. I cannot hear the tone but, can see it on a recording. I assume this would be the noise floor for the room? Is this realistic? This was done with a sound card and a simple Radio Shack mic. I also noticed that my computer (a seperate one from the one I did the recording on) which is being stored now had a siren type tone, high then low alternating, if I turned the volume all the way up with no source activated. If you kept the volume at regular levels then the tone could not be heard. So I think there is something going on just trying to dial it in and prove it. At least if I think I am hearing something then I can be sure it is me and not being influenced by someone maybe out of sight. If I find no evidence of foul play then I will make an appointment with the local shrink. My evidence thus far points to other things however.

You guys ever hear of MEMS? What about Bio-MEMS? A small transducer could be used to do some crazy things here.

Thanks for entertaing the thought. Schizoprenia or twilight zone et al. I wish it was that easy...LOL.

I am wide open to any test people may think might be revealing other than talking to a shrink . Would be nice to find an acoustics engineer local or someone in school who may want to take on a project.

[casper]

Another thing that is out there is a laser type device that can be pointed at say glass window and will reveal spoken conversation in the room from a distance. All kinds of crazy stuff out there.


http://www.osha.gov/dts/osta/otm/noi...trasonics.html


I read the above also and it seems to indicate that we may be picking up the "sideband(s)"? from AM modulation? Maybe these sideband(s) being in the audible range would be picked up by the SPL meter? At least in my case of measuring 71 DB in a quiet room. It puzzles me since I am hearing no loud noise in said room. The meter is picking up a very loud noise at 71 DB however. I have no way of calibrating this meter unfortunately. I seriously doubt it was that far out of wack.


Another theory. Like in car audio could we be getting a "cabin transfer" function from the room containing the infrasound being too small? I know when you put a subwoofer into a car you typically get a 6 DB gain. The basic reasoning is that the sound waves are longer than the car and are compressed thereby increasing SPL in the car. Could it be we are dealing with infrasound and the sound waves are longer than the room thus causing some kind of "cabin transfer" effect? Is this reaistic?


http://www.diracdelta.co.uk/science/...nd/source.html


Seeing the effects here many are the same or similar as schizoprenia .