[bfreedma]

Then you've got many great Swedish and Norwegian bands next door, It's niche music and has a relatively small following so I'm not surprised.



They did a song with Amon Amarth.

Yup. In the early days, they exclusively did Metallica covers but have broadened out since then.

 

[bigshot]

There's a quote in Evelyn Waugh's "The Loved One" where a character says, "The secret to getting along in Hollywood is to understand that everyone here speaks entirely for their own benefit. You aren't required to listen."

 

[gregorio]

Sorry about my laziness to try and find your explanation (for all the AI stuff and what not), but why wouldn't -30 dB SPL and 0.63... micropascals exist? Am I losing my mind?

Brownian Motion, although in practice the lowest level is somewhat higher than the theoretical limit dictated by Brownian Motion alone because absolute sound isolation can’t be achieved. The closest is MicroSoft’s anechoic chamber, which during the early hours one morning achieved -19.5dBSPL.

Calculating the Sound Pressure Level on bandwidth 20-20000 Hz I got 32 𝜇Pa (4 dB SPL). Calculating the noise level on the most sensitive band of human hearing (1000-6000 Hz) gives 5.2 𝜇Pa (-12 dB SPL).

-23.7dBSPL is the figure generally accepted I believe, although it varies a bit by temp, altitude and humidity of course, a fact @sunjam appears unable to comprehend, presumably because his virtual assistant didn’t consider it. I’m not quite sure how you arrived at your figure but it would make MicroSoft’s anechoic chamber measurement and a handful of other chambers, impossible to achieve without pumping the air out of the chamber. Either way, producing noise+distortion artefacts at -30dBSPL isn’t possible, even without considering the performance of transducers.

I think that is the answer @gregorio provided. (Please correct me if I am wrong)

Why do you keep saying “correct me if I am wrong”, what’s the point? I and others do correct you but you just ignore it and repeat the same BS. For example, another recent post:

You would lose your mind if you believe 1.000 != 1.001
Your mind would be "normal" again once your believe 1.000 = 1.001
More details here <== our discussion earlier

Exactly, you apparently don’t understand the basic concepts of “rounding”, “significant numbers/digits”, “degree of precision” or of physical limitations and despite it being explained to you several times by several different posters, you just repeat the same nonsense over and over. This not only demonstrates there is no point in correcting you but also invalidates your claims of critical thinking, a good learning technique and of a background in physics!

For your question "is your only response, deflection?" The answer is No.

You answer “No” but then you don’t address any of the issues and your only response is an unrelated and irrelevant question. As this is a perfect example of “deflection”, so you yourself have proven your answer is the exact opposite of the truth!

That seems to be a particularly bizarre trend in your posts: You claim “critical thinking” but demonstrate only the opposite, you claim a background in physics and then make assertions no one with such a background would ever make, you claim to be completely anti-pseudoscience and have training to identify it but then endlessly promote pseudoscience, you claim “a good learning technique” but never learn, etc., etc.

I’m trying to understand how you’ve arrived at the conclusion that consistently proving your own claims false (but just repeating them anyway) is a valid debating tactic? You seem incapable of rational thought or of telling the truth.

G

 

[Davesrose]

I’m trying to understand how you’ve arrived at the conclusion that consistently proving your own claims false (but just repeating them anyway) is a valid debating tactic? You seem incapable of rational thought or of telling the truth.

G

At one point sunjam was addressing whether he was an AI bot, or he was just utilizing AI to come up with all his answers. At this point, what is the difference? He's able to lasso a few folks to engage with his fallacies and keep on with this thread. When I've engaged, he pretty much confirmed he knows nothing about medical science (including psychology) no matter his claims. The more anyone will engage, I'm sure he'll still claim he's knowledgable about all these subjects and can teach all of us something.

 

[Quazar]

In our area, they say it like this:
He drinks wine and preaches water.

 

[71 dB]

Brownian Motion, although in practice the lowest level is somewhat higher than the theoretical limit dictated by Brownian Motion alone because absolute sound isolation can’t be achieved. The closest is MicroSoft’s anechoic chamber, which during the early hours one morning achieved -19.5dBSPL.

I don't remember how the anechoic chambers where I have been working were, but they were nowhere near as good as this MicroSoft anechoic chamber (Finnish universities don't have unlimited money like M$ has). One problem was the rubber insulators the chamber stood on had gotten stiff over decades and didn't insulate mechanical vibrations almost at all. The noise level at high frequencies was quite good, but torwards the low frequencies not so much. The largest chamber had 130 cm wedges and it was officially anechoic (less than 1 % of the sound reflected) down to 60 Hz or so. When the chambers were renovated (the wedges were replaced to material less harmful to users), it was my idea to raise the wedges below the steel wire mesh on "stands" in order to increase the absorption of lowest frequencies. A few years ago the facilities were renovated again and now the big anechoic chamber is allegedly the best in Europe (-2 dBSPL they say).

-23.7dBSPL is the figure generally accepted I believe, although it varies a bit by temp, altitude and humidity of course, a fact

There is a lot I don't fully understand about this. This is the first time I see Brownian motion mentioned in acoustics (or I have heard about this but I have completely forgotten about it). Do you know how this -23.7dBSPL is derived? Who, where and when has accepted this -23.7dBSPL figure?

Brownian motion in fluids, as far as I know, obeys -6 dB/octave spectrum (Brown noise has got its name from this), but the equations expressing Brownian motion in air seems to lead to +9 dB/octave spectrum! It is "violet" motion rather than "brown":

RMS pressure = (8𝜋𝜌kT*(f2^3-f1^3)/(3c))^0.5 => Power Spectral Density ∝ f^1.5

 

[bigshot]

It’s been clear what he is doing for almost a week. And it was clear where he was headed even before that. I don’t know why anyone would take a poster seriously when it’s so blatantly obvious he’s playing games. I have to conclude that he isn’t the only one who likes to spin his wheels and waste time.

 

[gregorio]

This is the first time I see Brownian motion mentioned in acoustics (or I have heard about this but I have completely forgotten about it). Do you know how this -23.7dBSPL is derived? Who, where and when has accepted this -23.7dBSPL figure?

TBH, I read the calculation of it many years ago but don’t recall where exactly. It’s typically quoted roughly, Eg:

https://interestingengineering.com/science/quietest-room-world-sound-goes-die - “The absolute minimum sound that can be experienced in any atmosphere as theorized by mathematicians is -23dB, or Brownian motion.”
Or
https://www.bbc.com/future/article/20170526-inside-the-quietest-place-on-earth - “It gets close to the limit of what should be possible to achieve without creating a vacuum – the noise produced by air molecules colliding with each other at room temperature is estimated to be about -24 decibels.”

G

 

[Ghoostknight]

Hmm interesting, so could we say everything under -104db at 80db peak level (normal max. listening position volume) is "definitely" inaudible?

i guess if we account for dither and headroom while playback we probably land with cd quality at -90db, this isnt too far off -104db

 

[71 dB]

TBH, I read the calculation of it many years ago but don’t recall where exactly. It’s typically quoted roughly, Eg:

https://interestingengineering.com/science/quietest-room-world-sound-goes-die - “The absolute minimum sound that can be experienced in any atmosphere as theorized by mathematicians is -23dB, or Brownian motion.”
Or
https://www.bbc.com/future/article/20170526-inside-the-quietest-place-on-earth - “It gets close to the limit of what should be possible to achieve without creating a vacuum – the noise produced by air molecules colliding with each other at room temperature is estimated to be about -24 decibels.”

G

One should be critical when reading sources like this. Not because the writers want to mislead the readers, but because the writers are not experts of a specific field like this (they are just people writing articles. They may have scientific background of a sort at best) and may write misleading things unintentionally. That's why I try to understand this topic well enough myself to be able to fact-check these claims myself, but the math/physics behind this is rather complex, perhaps not beyond my mental capabilities, but at least it requires time. I also find this interesting, because I never knew Brownian motion would be so close to human threshold of hearing!

 

[bigshot]

In my sig file is a seminar at the AES where they do a demonstration of taking a horrible buzzing noise and dropping it into music at progressively lower levels. When the buzz alarm sound hits -40dB, it is inaudible under the music.

Even without dithering, the noise floor of 16 bit is overkill.

The test file is available on the web so you can play it yourself.

 

[sander99]

Although this is almost certainly not what is happening here, still interesting:

"AI deception: A survey of examples, risks, and potential solutions"

https://www.cell.com/patterns/fulltext/S2666-3899(24)00103-X

 

[71 dB]

Hmm interesting, so could we say everything under -104dB at 80dB peak level (normal max. listening position volume) is "definitely" inaudible?

Well, anything below the threshold of hearing is inaudible. Around 3-4 kHz where the hearing threshold is lowest (good hearing), the means levels of about -85 dB below 80 dB. Assuming a superhuman listener whose hearing threshold is below Brownian motion, the Brownian motion would be heard as constant background ("hissing" I believe) noise + the quiet music partially or completely masked.

I guess if we account for dither and headroom while playback we probably land with cd quality at -90dB, this isnt too far off -104dB

Yes, but this is more than needed in practise. About 70 dB of dynamic range is need to cover even the most demanding listening scenarious of consumer audio and about 80 dB gives headroom/safety margin. This lands us to about 13 bits (78 dB). This doesn't mean we "need" a 13 bit digital audio format. It means 16 bit digital audio is more than enough for consumers. In studios in music production more bits can make life easier and 24 bit format is justified.

 

[bigshot]

The room you’re listening in has a room tone of at least 30dB, so to hear the quietest sound, you have to boost the level over that. Even with headphones you have a bed of room sound.

 

[gregorio]

One should be critical when reading sources like this.

Certainly, I was just citing examples of it being quoted. I read the actual calculation of it many years prior to these articles, probably around 20 years ago at a guess, either in an audio engineering journal or a scientific paper but I don’t recall exactly.

Hmm interesting, so could we say everything under -104db at 80db peak level (normal max. listening position volume) is "definitely" inaudible?

In the sense that; something that doesn’t exist obviously cannot be audible. If we were to take the absolute demonstrated audible limit which I believe was about -8dBSPL, then anything lower than -88dB (at 80dB peak) is “definitely inaudible”. However, that was demonstrated by a young child with perfect hearing in a world class anechoic chamber using a signal in the critical band (roughly 3kHz), conditions the average audiophile obviously cannot achieve! In practice the noise floor of your amp, transducers and listening environment will be significantly higher, as will the noise floor of the music recording you’re trying to reproduce, an audiophile’s hearing will not be as perfect as a young child with perfect hearing and peak level in the critical band will almost always be lower than the peak level of the music recording.

i guess if we account for dither and headroom while playback we probably land with cd quality at -90db, this isnt too far off -104db

If we account for dither and headroom, we “land with CD quality” at around -120dB (in the critical band), quite a long way beyond -104dB! Because we don’t need any headroom on playback and we use noise-shaped dither.

G