How quiet is "quiet?" Interesting article on special soundproof chamber

3 Likes

The quietest place that I have is anywhere I take out my hearing aids. Without them I really do not hear anything. Everything is quiet and peaceful. I have my very own peaceful place anytime I want.

3 Likes

with my tinnitus I have no quiet place at all, I have the most quiet with my aids on using the tinnnitus relief in my quiet office.

3 Likes

Part I found interesting is that they can measure a decibel level for molecules bouncing around.

2 Likes

What does the tinnitus relief sound like?

What I have is just a sound generator that is white noise, I can adjust it with the app to help cancel out my tinnitus. Some sort of tinnitus relief is built into most new hearing aids or are an option

Thanks. I was just curious what the sound was and guessed it would be some kind of white noise. I have a huge collection of sine waves in both ears that I’ve kind of gotten used to. I’m not sure white or pink noise would be soothing for me or not. Easy enough to test though. I have a few sources of it around here I could play with. I know waves or rain sounds wouldn’t help me much. Personal taste I guess.

my tinnitus is like a ringing and buzzing sound that gets louder depending if I open my mouth wide. the wider I open my mouth the higher the pitch… Audiologist told me not to open my mouth that wide. So used to the constant ringing it really does not bother me that much anymore.

1 Like

The sound can be set by your Audi to come as close as possible to your tinnitus issues. There was a time my tinnitus sounded like a military jet engine to me. But over the years it has become more an more just white or pink noise. I have had it so long that I nolonger let it bother me, but it is always there. And it is much worse when I have my hearing aids off. I have noticed here lately that my right ear is getting even worse.

The article is about how close to absolute quiet science can get, to hear molecules bouncing around,

Everyone wants to post about the internally generated noise in their heads and why they do not experience true quiet. :rofl: (I too have tinnitus, and old tube TV “off channel snow” sound.)

That is not what @MDB was trying to show and get a discussion going.

I remember 40 years ago, times in the mountains of Montana near Gannet Peak, 50 miles from any civilization, off the airline main traffic lanes, being about to hear rapids of a glacier fed river over two miles away, sitting in a meadow, breezes on the pines, birds twittering, chipmunks kicking leaves off soil, looking for seeds or pine nuts.

2 Likes

That is one of several limits on noise in microphones. If all the electric parameters are super-duper the Brownian motion of air molecules is audible. Assuming a super-quiet space (pressure cooker is traditional) you can read the thermal agitation on a meter. “Practical” microphones more often try to set the noise of several sources near-equal for best overall result. (A really low-noise microphone has no damping of the diaphragm and a very peaked response.)

It’s not necessary to measure. I believe Raleigh derived the answer before amplifiers just by thermodynamics.

Then again, I might be totally wrong on this, since your knowledge and experience on sound is more extensive than most of us here.

No. Or “sub-sub-sub-floor”.

How loud is the thermal motion of air molecules?

That thread wanders a bit. But thermal motion noise of air is in the range of -20dB SPL (note negative). The smallest sound that “normal” people can hear is -10dB to +10dB SPL (reference “zero” was picked in that range). Microphones designed for wide-range response do as good as +14dB SPL. Leading-edge HA mikes are 20 to 22dB SPL. I have done much “noiseless” recording with studio mikes above 25dB self-hiss.

I have worked/recorded in a room where the 3kHz hiss was -3dB SPL; it was a little spooky when empty. With ventilation and a hushed audience I never heard the hiss of 14dB SPL mikes. The ambient noise in a home is normally above 30dB SPL; urban residences over 38dB. Even my shack out in the woods is above 25dB SPL. (With 3 inches snow on the ground, and in a quarantine, late evening.)

Part of my paying-work used to be judging and sorting hisses. Room? Mike? Preamp? Tape? Playback? (And the odd noises: I had to tell my flautist boss to NOT wear those shoes because they made a hissy noise as his weight shifted- he never noticed.)

I have a LOT of that. And I am over-sensitive because to my working-mind it is “a problem”. (I’m retired but still have the habit.) And I am frustrated because I know I have lost my “hiss zone” and can’t trust my ears to sort one hiss from another.

But this “fizz” does not act like “equipment hiss”. Changing gain has little effect, and changing the “Highs” in the myPhonak app has nearly no effect. As far as I can tell, the “fizz” is between the speaker (my HA) and my brain. Like a room speaker in a room full of Sprite. But here the “fizz” must be my dysfunctional ear-nerves.

And like my numb-nerves leg which is improving with exercise, ear nerves do heal, slowly. The ear/brain needs long exposure to normal sounds so it can sort-out overtones as “structure” and not just treat it as random sounds. (“Tizz” because my high-frequency nerves are the most damaged.)

Not for everybody, but good for me: last night there was a pipe-organ competition on TV. I used to groove on pipe voicing; I know that in the last decade most such music has been atonal in the highs. After 3 months with my HA much of that sound was coming into focus again.

1 Like

As Paul no doubt knows, but most people don’t realize, the art of making low noise microphones and amplifiers to use with them is a whole field of engineering in itself. Not trivial at all. I can remember having good hearing and the wonderful things I discovered when it was really quiet. Such things are but a distant memory now.

1 Like

Any microphone with a sufficiently low mass diaphragm can suffer from the effect of Brownian Motion - that’s usually why minimum input levels have to be over 20dB to exceed the noise floor: despite one of the posters on this site being adamant that wasn’t the case.

1 Like

I don’t know about the Mohave desert but there are recordings of the sounds made by sand dunes in the Sahara.

The Mojave can be heard.

Without going into whether mass, stiffness, or resistance determines mike sensitivity, or the apparent similarity of Brownian versus “normal sound” motion…

Here’s an excerpt from a study of a new (for 1966) acoustic-studies microphone’s noise.


Solid curve is “silent air” including chamber leakage, Brownian, capsule acoustic resistance, amplifier hiss, and other factors. “Vacuum” reduces several of these noise sources, but changes their relationships. “Capacitor” replaces the whole transducer with equivalent electric part so is just the amplifier noise. They have made the amplifier a little better than the Brownian noise of this capsule.

1 Like

you’re lucky. I played with those but I found them all to be just noise on top of the whistle…

‘hello darkness my old friend’. The sounds of silence.

My tinnitus is white noise, so the sound machines do help me, and my tinnitus program in my aids is the same thing but I can adjust the low, middle, and high frequencies to help even more.
Yes there are times, mostly when there is a storm in the area, or if I have severe sinus issues that I will get what seems to be true tones, but that is very rare for me.