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Air Pressure and Balloons and Presence Near You

AudioTK

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I have an interesting topic... well it's something I've been fascinated with for many years... I didn't know exactly what section to post this, but this one seemed like the best fit.

It's a sensitivity to low frequencies. I'm a basshead (my best car audio system was a Cerwin Vega Stroker 18 with 2000wrms in a 1989 Honda CRX and hit 148.3dB), but in my early teens before I even had a car to put subwoofers, I would notice and pay attention to low frequencies. I notice HVAC duct air flow, I would even hear/sense thunderstorms way before other people would. Like I was in tune with the low rumbles of the distant thunder. Kind of like how a seashell amplifies noises when near your ear.

Another thing that I would notice is when I'm around balloons, not necessarily just filled with helium also when filled with air from breath or pump. If I walk past one or hold out at arm's length then bring in toward my head/ears, I could hear how it affected the ambient sounds that reached my ears differently than walking past solid objects like a box or a pole or something. Try it if you aren't sure what I mean. I would hear the change in the sounds, but I also felt like a pressure differential or something. I do also notice this with other objects approaching or present as well. Not sure what the exact phenomenon is called, but it was at some point when I realized I had that sensing capability (or just me being deeply in tune to it) when something was approaching, especially from behind me.

When I was old enough to work, I had a job at a grocery store. Bagging groceries, later stocking shelves, etc. I always liked to have fun and scare my coworkers all the time. They never knew where I was or when it would happen. I'd hide behind corners or displays or my favorite, I'd sneak up behind them super quietly then shout, "hey" or or poke them or something else to startle them. Anyway, they tried to do that to me as well. When I was busy stocking shelves as fast as I could, every time they tried to sneak up behind me as quiet as they could be, I would turn around right before they got to me. They would ask how did I know they were there because they were so quiet. Well, half the time, they were still making noises I could hear, but could sense the changing of ambient sounds as well as the pressure sensation like with the balloon. I'd say it was kind of like a "blind" test because of course I knew they would try to scare me at some point throughout the day, but I never truly knew when and I wasn't looking, just able to sense it.

All that to say, are there any equipment and/or microphones that could sense or detect stuff like I mention above. Of course barometers and microphones and other...? Or have any experiments been done to check similar? I'm curious if there are any report or papers. Like if a microphone is set up in a quiet office like I'm sitting in right now at 11:30pm (I hear my computer fan, the hvac, distant vehicles on the road as they pass, blood rushing in my ears), and you move an object slowly closer and closer toward the mic, would it read anything different? I think a barometer is too slow, and maybe it's not truly a "pressure" change I sense, but if I move a book or box closer to my ear, I can feel/sense it, if that makes sense.

If you were able to set up some sound or pressure detecting equipment, I'm sure it could detect thunderstorms 15 to 20 miles away and HVAC stuff, even if lower than the other ambient noises. But what about something like a balloon or other object approaching microphone(s) from various angles...? or a person slowly sneaking up from various angles to the sensors/microphones/etc? I might try to test in my unfinished home theater in my basement because it's got a pretty low noise floor, with one of my cheap microphones just to see if anything is measurable, or maybe someday buy/borrow a higher quality mic. If I can try this experiment, I will post some results/findings. I do know that the microphones will pick up ambient noise, but they can't pickup the blood rushing in my ears or my slow, silent breathing. So I am curious what can be measured.


I'm curious to hear thoughts on this.
Tom
 

restorer-john

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I think it's less about pressure and more about being sensitive to changes in reflected, local sound patterns. You co-workers sneaking up to you changed the reflected noises you were making stocking the shelves and that's what you picked up on/heard. Also, radiated heat is very easy to pick up, especially if your skin is exposed.
 
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AudioTK

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I think it's less about pressure and more about being sensitive to changes in reflected, local sound patterns. You co-workers sneaking up to you changed the reflected noises you were making stocking the shelves and that's what you picked up on/heard. Also, radiated heat is very easy to pick up, especially if your skin is exposed.
Yeah, that's pretty much what I am thinking as well. I'm just curious if that can be picked up by a microphone. Like start with nothing near, then move an object closer at some increments.
And yes, I am also tuned in or just pay attention to people's heat bubble.
 

Somafunk

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At some point in our lives we all believe we have an unusual and individual talent that is unique to us alone, this is never the case.
 
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AudioTK

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At some point in our lives we all believe we have an unusual and individual talent that is unique to us alone, this is never the case.
Yeah, I'm sure I'm not the only one. I am sure that not everyone pays attention to stuff like this though. There probably are some that do. I was just wondering if it could be measured when something approaches or is just present at some position near by versus when it's not there.
 

puppet

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images
 

mhardy6647

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I think it would be fun to fill a balloon with argon, or maybe something like sulfur hexafluoride.

There was, if memory serves, a commercial loudspeaker design that included an internal bladder filled with sulfur hexafloride to (I'm trusting my memory, here!) artificially alter the properties of the enclosure to "feel" larger to the woofer than it 'really' is.

EDIT: Well, I was close, at least. :)
https://audiosciencereview.com/foru...tionals-and-electrostatics.36320/post-1276525

 
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fpitas

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If SF6 is good enough for HV breakers, it's good enough for home speakers!
 

mhardy6647

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Speaking of balloons -- I saw one (of the passenger kind, not the espionage kind) over the Connecticut River here in the "Upper Valley" whilst on some errands in West Lebanon, NH this morning. Must be spring!
 

Andysu

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balloon popping testing and i may do more testings as first one was interesting

335903587_747163220296549_2494175539901168583_n.jpg
 

RayDunzl

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lowmagnet

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At some point in our lives we all believe we have an unusual and individual talent that is unique to us alone, this is never the case.
Yeah, it's not unique to any one of us, you just have to listen to the patterns around you. You'd be surprised about how much is around the noise floor of our consciousness that we automatically filter out unless we concentrate on the input.
 

scruffy1

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at that decibel level in your car, i am surprised your cochleas are still functioning
 

Cbdb2

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At some point in our lives we all believe we have an unusual and individual talent that is unique to us alone, this is never the case.
Yet everyone is different and has different sensitivities. He never said it was unique and its not. When I was still mixing I would spot low freq noise (rumble) that no one else could hear. This was always validated by the filters and meters.
 

Cbdb2

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Yeah, I'm sure I'm not the only one. I am sure that not everyone pays attention to stuff like this though. There probably are some that do. I was just wondering if it could be measured when something approaches or is just present at some position near by versus when it's not there.
People are great sound blockers/absorbers. Moving them around changes the sound dispersion in a room. It can be recorded. Gobo are used in studios all the time to change the sound reaching the mic. A person makes a great small gobo.
 

IAtaman

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I am not sure about your spider senses vis-a-vis your coworkers, but I suspect the balloons part might be due to "lensing" effect they might be creating.

Here is an interesting video about making 'sound lenses' with baloons:

 
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Cbdb2

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Sound lensing only works if the balloon is full of air with a different acoustic impedance (density etc.) than the atmosphere.
 
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