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I've been in a philosophical kind of mood as of late, and I've been pondering this question/concept for the past few days and I've love to hear others' thoughts and ideas on it. Not really a right or wrong answer to this, just something interesting to think about.

So The Planck length, 1.616199(97)×10− to the 35 is the smallest unit of measurement that we (or rather science I guess) deem as being realistically measurable, anything beyond which smaller unit would seem ludicrous and to some degree redundant.

It got me thinking about gain in an audio chain. Such as, using a mixer in front of a recorder to give yourself greater S/N to work with in quiet environments. If one were to, say, daisychain 100 (or even more) Sound Devices pres (or any other top-tier pres for that matter) to maximize available gain, how quiet of a sound could be picked up? What sort of noise or harmonics might be "capturable"? How about considering this realistically (considering the mic self noise, environment, etc) versus theoretical (mic has no self noise, environment is undisturbed quiet, etc)? Would it reach a threshold or tipping point at which greater noise would be introduced/summed than the gain availability we're creating for ourselves to begin with when daisychaining in more gain (sort of how zipping an MP3 makes it larger rather than smaller)? And furthermore, how does the cosmic radiation background (white noise, 'sound' of cooling photons which is still being electromagnetically picked up) play into this and does it set some sort of threshold precedent? I'm considering this question with the understanding as well that we're talking about proper gain staging, not running each pre at 100%

I'd love to hear thoughts and discussion on this, if anyone has science to share on it, I'd also love to hear as well. Sort of an out there topic but it's one which has had my mind pondering for some time.

  • Taking microsound to the next level. Or putting it differently. – Internet Human Jan 14 '13 at 15:41
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Hmmm....there's potential. I don't know about in a daisy-chain configuration, but maybe it would work in a [source > distributed network > summed signal] configuration. I will confess to having no direct experience with what I'm about to descrie; it's only something I've read about.

Because of the random quality of Brownian Noise, a signal that gets split, fed to matching electronics, and subsequently summed can have an increase in signal to noise ratio (from a purely electronics standpoint that is...I'll touch on that in next paragraph). A pair of signals from the same source that are summed, after nominal gain in each set of electronics, achieves a 6dB increase in level...while the noise floor from the electronics only receives a 3dB increase in gain. That means you've gained 3dB in the signal-to-noise ratio (note, this is only "self noise"). This was a trick that was used occasionally in analog recording. To my knowledge, this will not work in the digital domain, because there is a finite number of variations that can be present in a digitally encoded system. This will affect exactly how Brownian in nature the system noise is. The higher your bit and sample rate, the farther you might be able to go. But there will be a point of diminishing returns, and that point will be far earlier than the point that is capable with an analog signal.

Any sound not generated by the electronics is, in this case, signal; whether it's something you wanted to capture or not. Noise, as I was using it in the previous paragraph, refers only to that which is inherent to the electrical ciruits. I think the possibility of recording those commonly "imperceptible" sounds would be reliant on three factors:

  • Can the transducer actually react to those sounds?
  • What is the signal-to-noise ratio in the recording environment?
  • The number and quality of the components within the analog circuit.

If the transducer cannot react to those vibrations or [compressions + rarefactions], the sound cannot be recorded. If it can...then even if the sound is in the system's noise floor (remembering that many devices are still technically reacting to "signal," even if it is in the noise floor) then it is theoretically possible to get some information using that method mentioned above.

Of course, this would be a pointless exercise if any other sound in the environment is going to mask those commonly imperceptible sounds. There's a point of sound level separation where spectrum proximity is irrelevant to masking. If something is loud enough, it will mask the quieter sound (even if they occupy radically different locations within the sound spectrum). We won't be able to hear that target sound on reproduction...even though it is being recorded.

As to the number and quality of components...well...no real-world passive or active component operates at "ideal" potential. This would affect just how close to the ideal Brownian Noise the system comes...which would in turn affect your ability to achieve that ideal 3dB gain in signal-to-noise ratio.

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I think that there's a high chance that one wouldn't even need 100s of pres to figure out that there might just be constant and normal ambient noises everywhere around us, even when we think that things are quiet. Given that, one might not be able to extract any kind of "special miniscule sounds" in indoor or outdoor environments, because there's always some greater common sound somewhere (it might be coming from a long distance) that will be picked up with the extreme amplification. I don't think one could expect to hear anything surprising, because whatever that would be, it would be masked by something else. If you'd then try to do the recording in an anechoic chamber, well, you'd hear yourself. If you'd put only the microphone into the anechoic chamber, well, you'd pick up some common sound with the extreme amplification again.

I think there are only two possibilities here (and no surprises):

1) You'd pick up some common sound with extreme amplification (even if it's picked up from a long distance)
2) You'd pick up absolute silence (given that you try to place the extreme amplified setup in a theoretically silent environment in order to capture something "miniscule". But total silence is silence, thus you'll pick up silence.).

Now if you'd like to record atoms or subatomic particles, then I'd think you'd need to place the setup nearby some nuclear/particle physics experiment, preferably inside the accelerator or whatever they're using. That's a controlled environment at least. Although you'd be still dealing with the previous problems 1) and 2). Also, technically, you could be measuring rather than "recording", so I'd think you could also "hear" the sound that you're looking for by synthesizing the result of the experiment e.g. the movement of atoms or subatomic particles by using their theories in physics (the quantities would be some sort of frequencies and magnitudes and if there was a way to map that into some system that can play back that sound, e.g. by slowing down the created sound/signal to the audible range, then one could maybe be or would be able to hear it). However, if these quantities are smaller than the molecules of all known mediums that carry sound, then is there any "physical" sound at the subatomic level? Which means that computationally synthesizing the sound is actually the only way to capture it and you would also be measuring and synthesizing the highest theoretically known ultrasound frequencies.

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