The Shoutometer

[Blumlein 88]

Measures in terms of signal power...

Full Scale = one unit

-10db = 0.1
-20dB = 0.01
-30dB = 0.001
-40dB = 0.0001
-50dB = 0.00001
-60dB = 0.000001 Micro unit
-70db = 0.0000001
-80dB = 0.00000001
-90dB = 0.000000001 Nano unit
-100dB = 0.0000000001
-110dB = 0.00000000001
-120dB = 0.000000000001 Pico unit
-130dB = 0.0000000000001
-140dB = 0.00000000000001
-150dB = 0.000000000000001 Femto unit
-160dB = 0.0000000000000001
-170dB = 0.00000000000000001
-180dB = 0.000000000000000001 Atto unit

 

[Robbo99999]

Measures in terms of signal power...

Full Scale = one unit

-10db = 0.1
-20dB = 0.01
-30dB = 0.001
-40dB = 0.0001
-50dB = 0.00001
-60dB = 0.000001
-70db = 0.0000001
-80dB = 0.00000001
-90dB = 0.000000001
-100dB = 0.0000000001
-110dB = 0.00000000001
-120dB = 0.000000000001
-130dB = 0.0000000000001
-140dB = 0.00000000000001
-150dB = 0.000000000000001
-160dB = 0.0000000000000001
-170dB = 0.00000000000000001
-180dB = 0.000000000000000001

Is that right? I thought -6dB was a halving of power, therefore -6dB would bring you from 1.0 down to 0.5....then if you turned it down another another -6dB on top of that (to make total -12dB) would be halving it again to make 0.25.....so I don't see how -10dB can be 0.1?

 

[RayDunzl]

Is that right? I thought -6dB was a halving of power, therefore -6dB would bring you from 1.0 down to 0.5

Power varies with the square of the voltage, so they can't be compared as equals.

http://www.sengpielaudio.com/calculatorVoltagePower.htm

Referring back to the table in the previous post, it compared declining deibels of power with the declining ratio of power

If Power is the left column, and the Voltage to create it is on the right, it most conveniently looks like this starting with 1V:

If -0dB of power = 1V in a circuit of 1 ohm and 1 amp

-10dB = -.316V
-20dB = -.1V
-30dB = -.0316V
-40dB = -.01V

 

[Webninja]

I like how this makes things more tangible, but are there presumed terrain defaults? A busy city vs an empty valley. Although this only matters for the closer distances.

 

[RayDunzl]

I like how this makes things more tangible, but are there presumed terrain defaults? A busy city vs an empty valley. Although this only matters for the closer distances.

No, it assumes only -6dB per doubling of distance with an initial baseline of 1 meter.

No other losses or gains from any conditions that may exist in the "real world".

A contrived theoretical exercise, like measuring light in a vacuum, which, as we know travels farther than across a foggy lake.

You can derate the numbers as you see fit to satisfy your own conditions.

---

My Audio Buddy lives close (1400'/430m) to an always busy interstate highway.

Depending on the microclimate of the evening, you can hear the traffic clearly, or not at all, from his front porch, facing the highway.

 

[BDWoody]

I like how this makes things more tangible, but are there presumed terrain defaults? A busy city vs an empty valley. Although this only matters for the closer distances.

Not related to terrain defaults, but I found this a while ago related to atmospheric attenuation as it relates to frequency, humidity... Some interesting stuff, but haven't worked it into Ray's spreadsheet to see how it changes things.

From http://www.sengpielaudio.com/AirdampingFormula.htm

 

[Blumlein 88]

Not related to terrain defaults, but I found this a while ago related to atmospheric attenuation as it relates to frequency, humidity... Some interesting stuff, but haven't worked it into Ray's spreadsheet to see how it changes things.

From http://www.sengpielaudio.com/AirdampingFormula.htm

View attachment 84947

View attachment 84949

Temperature inversions can funnel sound as well. I think that is what Ray is experiencing with his buddy close to the highway.

I worked at a place that was in something of a large bowl like depression. We'd get temperature/humidity inversions many nights. You could walk up and down a hill at the entrance. Cross over into a trapped foggy high humidity layer which was maybe 5 degrees cooler than the air trapped below and the sound you heard changed dramatically. That layer could funnel sound from all the way across that depression very clearly. Step down a few feet below it and you couldn't hear the distant sound. Such things are common around ponds or lakes as long as there isn't much wind to stir things up.

Here is a page about inversions funneling sound.
https://www.mocpa.com/inversion.html

 

[Robbo99999]

Power varies with the square of the voltage, so they can't be compared as equals.

View attachment 84940

http://www.sengpielaudio.com/calculatorVoltagePower.htm

Referring back to the table in the previous post, it compared declining deibels of power with the declining ratio of power

If Power is the left column, and the Voltage to create it is on the right, it most conveniently looks like this starting with 1V:

If -0dB of power = 1V in a circuit of 1 ohm and 1 amp

-10dB = -.316V
-20dB = -.1V
-30dB = -.0316V
-40dB = -.01V

Ah, I must have been referring to the Voltage rather than the Power, I didn't know the distinction.

 

[GDK]

Here in Canada, it is more likely that you would have to deal with the acoustic attenuation from freshly-fallen snow.

https://www.igsoc.org/journal/61/228/t15j040.pdf

 

[weasels]

This is a phenomenally helpful way to understand how much I should care about performance beyond a certain point.

With my volume at max I couldn't hear anything beyond -84dbfs.

 

[RayDunzl]

Ah, I must have been referring to the Voltage rather than the Power, I didn't know the distinction.

Two formulas:

dB = 10 log (P2/P1)
dB = 20 log (V2/V1)

http://www.hottconsultants.com/techtips/decibel.html

 

[Cbdb2]

All true except the source is not omni. Shouting is directional so you need to add some gain. Like using a passive megaphone dosnt add power just directionality.

 

[Cbdb2]

No, it assumes only -6dB per doubling of distance with an initial baseline of 1 meter.

No other losses or gains from any conditions that may exist in the "real world".

A contrived theoretical exercise, like measuring light in a vacuum, which, as we know travels farther than across a foggy lake.

You can derate the numbers as you see fit to satisfy your own conditions.

---

My Audio Buddy lives close (1400'/430m) to an always busy interstate highway.

Depending on the microclimate of the evening, you can hear the traffic clearly, or not at all, from his front porch, facing the highway.

Highway noise ( infinite line) dosnt follow 1/r^2 reduction just 1/r and infinite plane no reduction from distance.

 

[krabapple]

Measures in terms of signal power...

Full Scale = one unit

-10db = 0.1
-20dB = 0.01
-30dB = 0.001
-40dB = 0.0001
-50dB = 0.00001
-60dB = 0.000001 Micro unit
-70db = 0.0000001
-80dB = 0.00000001
-90dB = 0.000000001 Nano unit
-100dB = 0.0000000001
-110dB = 0.00000000001
-120dB = 0.000000000001 Pico unit
-130dB = 0.0000000000001
-140dB = 0.00000000000001
-150dB = 0.000000000000001 Femto unit
-160dB = 0.0000000000000001
-170dB = 0.00000000000000001
-180dB = 0.000000000000000001 Atto unit

So, golden ears fussing over what they 'hear' at -90 dB are just nanoing on.

 

[earlevel]

All true except the source is not omni. Shouting is directional so you need to add some gain. Like using a passive megaphone dosnt add power just directionality.

But wouldn't that gain simply be part of the initial condition, and as long as you stayed on the centerline of that radiation as you increased distance, the numbers in Ray's tables should hold? This is assuming things like no wind, but that would have to be true for a point source as well.

Anyway, it a little hard to wrap your head around these numbers, but having been in quiet, open, windless places, I can imagine to a degree. Like, I can wrap my head around -60 dB being a kilometer away. -90 dB being 33 km get a bit tough, but ok, perfect conditions—and I know how loud that is on my studio monitors, relative to loud monitoring level. -144 dB at the distance of New York to Tokyo...well, the only thing I can say is I know people can't hear that far down, but lot of people claim it.

 

[Endibol]

We've all seen the Sound Pressure Level decibel reference tables where you have "quiet room", "chainsaw", "jet engine" and so on.

While that is handy for estimating increased loudness in decibles, it didn't help me when thinking about the measurement levels obtained around here when measuring electrical deficiencies (DAC output, distortion, frequency spikes, etc) in reference to the device's Full Scale output.

Here's my handy ballpark reference going the other direction, when trying to "imagine" sound that is "softer" than another by some number of decibels.

Assuming:

Sound propagation (ignoring loss in air, and any other complications) and using the general formula where a doubling of distance is equal to a 6dB drop in the sound level...

Someone is shouting at you from a meter away (representing 0dB, the "full scale reading", a loud sound, surely somewhat equivalent to a not unreasonably loud stereo system playing in your room)...

Then...

This handy table estimates the distance of a second Shouter at various distances and diminishing sound levels, relative to the full scale Shouter shouting from 1 meter away.

If you think it is bogus (a little inaccurate doesn't count as a fault here), please explain why.

Shoutometer™

View attachment 11832

Shoutometer DeLuxe

View attachment 60172


Measures in terms of signal power...

Full Scale = one unit

-10db = 0.1
-20dB = 0.01
-30dB = 0.001 milli Units
-40dB = 0.0001
-50dB = 0.00001
-60dB = 0.000001 micro units
-70db = 0.0000001
-80dB = 0.00000001
-90dB = 0.000000001 nano units
-100dB = 0.0000000001
-110dB = 0.00000000001
-120dB = 0.000000000001 pico units
-130dB = 0.0000000000001
-140dB = 0.00000000000001
-150dB = 0.000000000000001 femto units
-160dB = 0.0000000000000001
-170dB = 0.00000000000000001
-180dB = 0.000000000000000001 atto units

This is great Ray, it certainly put things in perspective and shows how ridiculous the statements of certain people are regarding their hearing capabilities (Rob Watts).
One also started wondering why there is still so much focus on pushing SINAD-numbers down.

 

[Endibol]

I think part of the reason is that the Shoutometer is overestimating the distances because it's not taking air atmosphere absorption into account so it's making it sound quite a bit more hyped up and unreasonable to expect better SINADS from audio gear. For instance at this link (http://www.sengpielaudio.com/calculator-air.htm ) if you take telephony frequency of 300Hz to 3000Hz to describe a human voice and plug some different frequencies into the calculator at that link you have for instance the following to describe just the effects of the atmospheric air absorption variable part of the overall equation:
0.2dB/100m of attenuation at 300Hz
1.8dB/100m of attenuation at 3000Hz
0.8dB/100m of attenuation at 1650Hz
So we could call it maybe 1dB/100m of attenuation just by the air itself on the identification (not necessarily intelligibility) of a human shout out in the real world.

If we factor the 1dB/100m into the shoutometer table then lets look at the -60dBFS reading that is showing 1km (or 1000m) - so if we factor in the 1dB/100m then we have to add another 10dB of attenuation onto that, so that would make it to be actually -70dBFS at 1km. Another example is the 500m one would turn into -59dBFS. These effects get even greater magnified the further you go down the shoutometer scale as distance is increasing logarithmically. So really the air absorption has a big effect. So I think this puts the table a little more into perspective and might go some ways to explain how you (@MRC01 ) can hear differences when it seems absolutely unreasonable from the shoutometer table. Just some thoughts and rough calculations I've worked out....haven't really worked out all the implications on what we're talking about, but figured it was significant to point out given it's large effect on the table, especially at the lower dBFS.

These calculations about absorption are very interesting. However not relevant regarding the point Ray wants to make with his “shoutometer thought experiment”: showing how low for instance -100 dBfs already is and why it doesn’t make sense to even think you can hear lower levels.
In your living room the absorption is a constant and negligible factor.

 

[Mart68]

Not related to terrain defaults, but I found this a while ago related to atmospheric attenuation as it relates to frequency, humidity... Some interesting stuff, but haven't worked it into Ray's spreadsheet to see how it changes things.

From http://www.sengpielaudio.com/AirdampingFormula.htm

View attachment 84947

View attachment 84949

I have a question about this:

My room varies from 40% to 70% humidity which at 10Khz is 1dB of attenuation. But that's over 30 metres of distance.

To get the figure for 3 metres of distance would I just divide by 10? So at 70% humidity there would be 0.1dB of attenuation compared to 40% humidity. Or is it not that simple?

 

[Robbo99999]

These calculations about absorption are very interesting. However not relevant regarding the point Ray wants to make with his “shoutometer thought experiment”: showing how low for instance -100 dBfs already is and why it doesn’t make sense to even think you can hear lower levels.
In your living room the absorption is a constant and negligible factor.

You've misunderstood it. Air absorption is greatly relevant in relation to the shoutometer. The distances are greatly exaggerated in the shoutometer due to the fact he didn't take into account air absorption. Given the shoutometer was designed to illustrate in practical terms how absurd it would be to hear certain low level sounds then the distance exaggeration of the shoutometer over eggs it & incorrectly makes it seem even more absurd that a person could hear low level sounds. I'm not arguing about exactly at what low level a person can detect something, but what I am saying is that the shoutometer is an innacurate exaggeration because air absorption has not been taken into account - so it's an exaggerated analogy. I'm simply commenting that air absorption should have been factored into it to make it a more accurate analogy. You've missed the point, as air absorption in your living room is absolutely no part of the point I'm making.

 

[Endibol]

You've misunderstood it. Air absorption is greatly relevant in relation to the shoutometer. The distances are greatly exaggerated in the shoutometer due to the fact he didn't take into account air absorption. Given the shoutometer was designed to illustrate in practical terms how absurd it would be to hear certain low level sounds then the distance exaggeration of the shoutometer over eggs it & incorrectly makes it seem even more absurd that a person could hear low level sounds. I'm not arguing about exactly at what low level a person can detect something, but what I am saying is that the shoutometer is an innacurate exaggeration because air absorption has not been taken into account - so it's an exaggerated analogy. I'm simply commenting that air absorption should have been factored into it to make it a more accurate analogy. You've missed the point, as air absorption in your living room is absolutely no part of the point I'm making.

@Robbo99999 I see your point now, I was too fast in my response. Basically you propose a substantial correction to the Shoutometer. My conclusion is that you made relevant correction to the Shoutometer that still serves its intended purpose.