Dynamic Range: How Quiet is Quiet?

[OWC]

Although this is already a somewhat older post, I really would like to put a few things in perspective.
Actually this applies to a lot of conclusions being made on some articles on this forum (or maybe even in audio in general).

What I am really missing is some sense of context.
What I noticed is that most experiments (and conclusions) are done from a home/room type of environment.
There is nothing wrong with that on itself, but the story is sometimes totally different when using the same tools in a different environment.
One good example is a line-array system with something like 24 high-sensitive compression drivers with horns or waveguides.

In that case I can guarantee that everything worse than around 115dB SNR is just going to be very nasty.
Same goes for the other extreme, where the sensitivity of the drivers isn't an issue, but the fact that the environment is very quiet.

To put this in perspective, an average living room is actually a very easy environment.
So to answer the question; how quiet is quiet?
Well, that totally depends on the context and environment.

 

[MRC01]

I have a recording for testing dynamic range. It starts in a quiet park, the digital signal level is around -85 dB. This goes on for a while then a jet flies nearby and the signal smoothly goes to digital signal level 0 (just shy of digital clipping). When I play in my listening room, when the loudest part peaks at 106 dB SPL (measured at the listener position with an SPL meter, and it's broad spectrum so the meter is reasonably accurate), I can still hear the quiet part at -85 dB. Of course I can't measure the quiet part with my SPL meter because it's far too quiet. Assuming the system or speakers aren't compressing the signal, it should be 21 dB SPL. My room is in the basement and well insulated, so it's pretty quiet. But I don't think it can be THAT quiet. The sound should be below the noise floor of my room, but I can still hear it. On old RCA victor recordings from the 60s, one can discern low level musical detail in the tape hiss. Our ears/brains are pretty good at discerning correlated signals even when buried in noise.

 

[Dmitriy]

I wanted to ask if we have an audio track, say, with a dynamic range of 12 units, will this mean that it will fit in 2 bits, or do I misunderstand this?

 

[MKreroo]

I have some questions about this:

regarding the 20bits conclusion, for an average user, so:
- from the graph, the avg room seems to be around some 10-15db SPL above the threshold?
- given that most people won't be listening at 130 dB SPL, and from this thread, it seems that most listen at around 75-85 dB SPL, would it be safe to assume that 16bits soure is more than likely to be sufficient for most people (I get that >20bits are better since it "works" in even the most extreme situation)
- assuming one were to stick with health guideline such as the 70dBA suggested by Health Canada (as an example here), it seems that the available dynamic range would be limited, how can one achieve higher DR without compromising hearing?

My understanding of this is still rather shallow so sorry for any stupid question.

I also found this, which
"It gets worse when you present the sound to the ear directly with headphones—then, it takes about 45 dB to be just audible at 125 Hz. The difference is primarily due to vascular noise of the blood running through our blood vessels."
seems to explain the reasoning behind the threshold for human?

Thanks

 

[Dj7675]

I have some questions about this:

regarding the 20bits conclusion, for an average user, so:
- from the graph, the avg room seems to be around some 10-15db SPL above the threshold?
- given that most people won't be listening at 130 dB SPL, and from this thread, it seems that most listen at around 75-85 dB SPL, would it be safe to assume that 16bits soure is more than likely to be sufficient for most people (I get that >20bits are better since it "works" in even the most extreme situation)
- assuming one were to stick with health guideline such as the 70dBA suggested by Health Canada (as an example here), it seems that the available dynamic range would be limited, how can one achieve higher DR without compromising hearing?

My understanding of this is still rather shallow so sorry for any stupid question.

I also found this, which
"It gets worse when you present the sound to the ear directly with headphones—then, it takes about 45 dB to be just audible at 125 Hz. The difference is primarily due to vascular noise of the blood running through our blood vessels."
seems to explain the reasoning behind the threshold for human?

Thanks

I found @amirm’s video on how loud is loud helpful. The frequency is very important... 75dB @ 20hz is very different than 75dB at 3khz.

Music: how loud is loud? (video)

Here is a much needed video on the topic of how loud we really listen to music. And issues related to hearing damage, etc. It is an argument that seems to come up twice a day since I started testing headphones. Here, I review the literature on true dynamic range of music and considerations...

www.audiosciencereview.com

 

[NTTY]

The bit that made me smile was remembering a procession of females arriving at the labs to have their voices recorded, appropriate noise added and these signals transmitted to various transducers set in flight and tank helmets. How a fighter pilot ever understood a word that was said to him astounded me.
I’ve often wondered if we ‘interpret’ rather than analyze when we listen to music.

Sorry, old post, but that might be related to the "Stapedius Reflex" (Acoustic Reflex) whereby the ear will protect itself from loud sounds. Acoustic Reflex will reduce masking below 2000Hz, where we have human voices. When placed in a loud environment, our ear will therefore unconsciously improve understanding of voices.

 

[Shadrach]

I think the latency in the reaction is too slow in the time ranges we dealt with.

 

[Suffolkhifinut]

Another view on dynamic range. Stopped buying blu ray discs if I had the volume high enough to hear the quiet passages the loud passages were deafening. For me dynamic range should allow the quietest passages and the loudest passages to cohabit.

 

[Andysu]

online hearing test with Denon AVC-X8500H volume at 0.0dB headphones sennheiser hd559 .
and playing the sine wave hear test tones at lowest level until i can hear the tone within a quiet room with no external noises .
i can barely hear the faint tones at -99dB which i guess is good and as hearing range changes or less sensitive to lower frequencies i need to increase dB level same applies to certain high frequencies.

i have used the free online hearing test for years now .
https://newt.phys.unsw.edu.au/jw/hearing.html

so that is what i could hear . that's my threshold .

 

[Alexium]

Another view on dynamic range. Stopped buying blu ray discs if I had the volume high enough to hear the quiet passages the loud passages were deafening. For me dynamic range should allow the quietest passages and the loudest passages to cohabit.

Yes, many movies have this problem. I would like a little bit of dynamic compression, and it's easily doable if playing from a PC. AVR makers should implement this option.

 

[Alexium]

i can barely hear the faint tones at -99dB

Can you listen to 1 kHz or 3 kHz at the same 0 dB setting in these heapdhones without it being too painful? If not - and I suspect this is the case - then the -99 dB figure is in reality lower (smaller absolute value, maybe -80 dB).

 

[MRC01]

Another view on dynamic range. Stopped buying blu ray discs if I had the volume high enough to hear the quiet passages the loud passages were deafening. For me dynamic range should allow the quietest passages and the loudest passages to cohabit.

Yes, many movies have this problem. I would like a little bit of dynamic compression, and it's easily doable if playing from a PC. AVR makers should implement this option.

I like wide dynamic range. I have a quiet listening room which helps to enjoy it. Compression can't be undone, so the ideal way is for the disk to have full dynamic range, and the player or DAC can provide real-time dynamic compression for those who want it. All the DVD/BluRay players I've seen provide this feature.

 

[Suffolkhifinut]

I like wide dynamic range. I have a quiet listening room which helps to enjoy it. Compression can't be undone, so the ideal way is for the disk to have full dynamic range, and the player or DAC can provide real-time dynamic compression for those who want it. All the DVD/BluRay players I've seen provide this feature.

Can fully understand what you’re saying, however my concern also was the damage to hearing. God knows what the db level,was when the action scenes came on. Stopped going to the cinema for the same reason. It’s an attitude that’s paid dividends my hearing is still good.

 

[jooc]

"So it turns out we need high resolution audio (i.e. > 16 bits) after all if we want to make sure our distribution channel, i.e. recorded digital samples, does not add more noise than the rest of the chain. No cassette decks may apply."

It's remarkable how the technical realms of photography and audio share so many similar patterns. This same argument applies to image dynamic range, in the image processing chain you need a certain threshold of bits to allow necessary headroom.