• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

How quiet is -60dB?

617

Major Contributor
Forum Donor
Joined
Mar 18, 2019
Messages
2,403
Likes
5,296
Location
Somerville, MA
Just a quick visualization I made to indicate how quiet -60 dB is. Imagine each of these construction workers is yelling at you. Assuming the first figure is 6' away, each successive figure is twice the distance, or -6 dB further.

Pretty amazing to think that -96 dB is equivalent to about 18 miles away, and -120 dB about 297 miles. 144 dB, at least in theory, corresponds to a construction worker yelling at you from 4700 miles away.

how-quiet-is-60db.jpg


If you were in Central Park, Manhattan, the -120db construction worker could be in Baltimore.
1613497886987.png
 

Absolute

Major Contributor
Forum Donor
Joined
Feb 5, 2017
Messages
1,084
Likes
2,125
Could be, but this implies that any distortion below -50 or so is inaudible, making me question the validity of the claim. If I play 1 khz at 0 dB and 3 khz at -50, is the latter inaudible?
 
OP
617

617

Major Contributor
Forum Donor
Joined
Mar 18, 2019
Messages
2,403
Likes
5,296
Location
Somerville, MA

solderdude

Grand Contributor
Joined
Jul 21, 2018
Messages
15,891
Likes
35,912
Location
The Neitherlands
Could be, but this implies that any distortion below -50 or so is inaudible, making me question the validity of the claim. If I play 1 khz at 0 dB and 3 khz at -50, is the latter inaudible?

It depends on how far the harmonics are removed from the fundamental and at which frequency it is (masking).
Tones and music are different things.
A S/N ratio of 50dB is audible because the average level of music will be 10-20dB below peak from which S/N ration is calculated.
Noise will thus be 35dB down below average music levels.
It also will depend on how loud the peak/average SPL is.
In music our dynamic range is about 70dB, add 20dB and 90dB S/N ration is fine.

Unless you have gear that can reach 120dB peak and you want absolute silence standing close to the speakers. In that case you may need 120dB S/N ratio because standing close to the speakers you want silence but you listen further away (lowering the noise at the listening position)

Also those that listen for noise 10cm away from their tweeter but listen 2 meters away to music will need a much higher S/N ratio than those that only care about noise at the listening position. The picture of the working men illustrates this well.

When your distortion products are not masked they also need to be low but because these distortion products are narrow in BW and noise is wide distortion can be a bit higher than noise before it becomes audible. For nasty sound you need substantial amounts of distortion (depending on music content as well because this can mask)

Some folks are bothered by noise, others less so. Also noise spectrum matters. It's complex, certainly with music.

Needless to say... It is not extremely costly nor difficult to build electronics with low noise and distortion (high SINAD). For vinyl and mics this is another matter and getting low noise is a bit more demanding/difficult.
 
Last edited:
OP
617

617

Major Contributor
Forum Donor
Joined
Mar 18, 2019
Messages
2,403
Likes
5,296
Location
Somerville, MA
I did this to help illustrate how big a difference 6db makes, and to help visualize distortion levels in devices that actually have audible distortion (speakers). If you try to limit distortion to under 1%, which is quite good for a speaker, this corresponds to -40db below fundamental.
 

paulraphael

Active Member
Joined
Dec 18, 2020
Messages
262
Likes
367
Location
Brooklyn, NY
I did this to help illustrate how big a difference 6db makes, and to help visualize distortion levels in devices that actually have audible distortion (speakers). If you try to limit distortion to under 1%, which is quite good for a speaker, this corresponds to -40db below fundamental.

Oh yeah, I know from informal tests that I can't hear 1% distortion in music. I can hear it in a sine wave, but not easily. Maybe it's easier with some other kinds of distortion (the test I used was pure harmonic distortion I believe). And maybe my headphones already produce this much distortion.
 

solderdude

Grand Contributor
Joined
Jul 21, 2018
Messages
15,891
Likes
35,912
Location
The Neitherlands
As a New Yorker with golden ears, I have to say that Baltimore construction worker is really starting to piss me off.

Then stop letting that Baltimore guy doing your renovations in your New York apartment while you are there... :cool:
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,522
Likes
37,052
I did this to help illustrate how big a difference 6db makes, and to help visualize distortion levels in devices that actually have audible distortion (speakers). If you try to limit distortion to under 1%, which is quite good for a speaker, this corresponds to -40db below fundamental.
Yes, and you did a good job.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,522
Likes
37,052
Could be, but this implies that any distortion below -50 or so is inaudible, making me question the validity of the claim. If I play 1 khz at 0 dB and 3 khz at -50, is the latter inaudible?
Worse is if you play 18khz and 20 khz with -50 db IMD. You'll likley not here either tone, but the 2 khz at only 50 db down will be obvious. Nothing to mask it at all.

WARNING: DO NOT REALLY do this or you'll need new tweeters.
 

danadam

Addicted to Fun and Learning
Joined
Jan 20, 2017
Messages
956
Likes
1,496
Could be, but this implies that any distortion below -50 or so is inaudible, making me question the validity of the claim. If I play 1 khz at 0 dB and 3 khz at -50, is the latter inaudible?
AFAIK audibility of pure tones is better than more complex signals. On top of that, 3 kHz happens to be around the range of highest sensitivity of human hearing. In attachment you can find a 3 kHz beep at -50 dBFS mixed with a continuous 1 kHz tone at -0.1 dBFS:

tones.png

And in part 3 of "Audio Myths Workshop" (at 32:00) there are examples of some nasty noise added to music at different levels:
 

Attachments

  • tones.flac.zip
    579.3 KB · Views: 104
OP
617

617

Major Contributor
Forum Donor
Joined
Mar 18, 2019
Messages
2,403
Likes
5,296
Location
Somerville, MA
Also, and this never occurred to me before, but you can now get audio devices for under two hundred dollars with a SINAD of 120db. That's an incredibly low figure when you really think about it.

We really need to start using a linear rather than logarithmic scale to quote these distortion and noise figures.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,522
Likes
37,052
Also, and this never occurred to me before, but you can now get audio devices for under two hundred dollars with a SINAD of 120db. That's an incredibly low figure when you really think about it.

We really need to start using a linear rather than logarithmic scale to quote these distortion and noise figures.
120 db is simple.

It is a ratio of 1 million to 1.

Distortion is 1 ppm.

Or in the case of SINAD, all harmonic distortion combined, along with all noise combined is 1 ppm.
 

Frank Dernie

Master Contributor
Forum Donor
Joined
Mar 24, 2016
Messages
6,445
Likes
15,780
Location
Oxfordshire
Could be, but this implies that any distortion below -50 or so is inaudible, making me question the validity of the claim. If I play 1 khz at 0 dB and 3 khz at -50, is the latter inaudible?
I have tested myself.
If I reduce the level by 60dB from my normal listening level I can not hear anything. From this I deduce that this idea that I would be able to hear a distortion product at -60dB is quite ridiculous, so -50dB being inaudible too seems highly likely.
I always, as an old fashioned type of engineer, try to get a real feel for the numbers in my measurements and others may find something different, but I find all of this first post completely logical and easily believable based on my own measurement and test experience.
 

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,223
Likes
17,800
Location
Netherlands
These comparisons to distance don’t really work for me. They suppose that there is no noise at all in the environment and also that it’s free space. Neither of these are a reality and therefore I cannot really imagine hearing a worker 18 miles away. Note that your average home noise is already around 40dB. Distortion products needs to first get louder than this noise to be able to hear them.
 

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,423
Likes
7,940
Location
Brussels, Belgium
Note that your average home noise is already around 40dB. Distortion products needs to first get louder than this noise to be able to hear them.

This is not completely correct, our ears are designed to pick up reverberations that we are unfamiliar with. so if that noise is consistent (so we get used to it), we could pick up sound at the loudness of the noise (or lower). Specially in the frequencies we're most sensitive to.

Otherwise we would all be practically deaf on a plane. or we would not tell where the predator is among a herd.
 
Last edited:

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,522
Likes
37,052
These comparisons to distance don’t really work for me. They suppose that there is no noise at all in the environment and also that it’s free space. Neither of these are a reality and therefore I cannot really imagine hearing a worker 18 miles away. Note that your average home noise is already around 40dB. Distortion products needs to first get louder than this noise to be able to hear them.
Don't over-simplify.
Here is a noise floor I recorded last night at my house. It was late so rather quiet. Notice how low the noise is above 3 khz. While the noise level was just over 40 db SPL, portions are quiet and would not obscure distortion artifacts in those frequency ranges.

1613506814458.png
 

MRC01

Major Contributor
Joined
Feb 5, 2019
Messages
3,424
Likes
4,030
Location
Pacific Northwest
Here's an experiment you can try. In a quiet environment it's not unusual to score -60 dB or lower. And that understates what we can actually hear. This experiment only tests your short-term dynamic range acuity. Long-term dynamic range is wider because the ear uses biological compression mechanisms to compensate.
 

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,223
Likes
17,800
Location
Netherlands
This is not completely correct, our ears are designed to pick up reverberations that we are unfamiliar with. so if that noise is consistent (so we get used to it), we could pick up sound at the loudness of the noise (or lower). Specially in the frequencies we're most sensitive to.

Otherwise we would all be practically deaf on a plane. or we would not tell where the predator is among a herd.

All true, but all your examples are about the primary signal. But we’re talking about distortion products, so harmonics of the original signal. I don’t think you can extrapolate your line of thinking this way.
 
Last edited:
Top Bottom