Originally Posted by imagic
IMO you exaggerate the importance of HDMI jitter while simultaneously understating the importance of a low noise floor in a listening room. I find that a bit baffling since the addition of acoustical room treatments and sound isolation are among the best sound-quality upgrades you can make, for any system.
I disagree with the final quote in your article: "two ears and a brain are much more analytical than a microphone and a meter!" Whose ears are referred to in that quote? Anyone's ears? Or a trained pair of exceptional golden ears, as verified through ABX testing?
If that's really true that ears beat a mic and a meter (which for the sake of argument is a computer running measurement software), can you explain why it's so difficult for two ears and a brain to accurately measure sound levels, distortion, frequency range, and etc.? It sounds like the same argument made by the guys who think they can calibrate a TV by sight, instead of using a meter.
Personally, I'd go with "two ears and a brain are a lot more holistic than a mic and a meter"
Thank you for your comments. Alas, it is an emotional response based on what I call "forum science." When presented with real science that disputes the "common forum wisdom" the reaction is always the same: denying the science! And blaming the messenger.
In this case you were reading a published paper. Thousands of people have read it there and not one person had written in to say, "this is all wrong." On the contrary, when I go to trade shows people always compliment me on a few of my papers and this is one of them.
I wish I could take credit for the knowledge within that article but alas, I can't. I am standing on tall shoulders of luminaries in audio science. They are listed in the references:
“Noise: Methods for Estimating Detectability and Threshold,” Stuart, J. Robert, JAES Volume 42 Issue 3 pp. 124-140; March 1994
“Dynamic-Range Issues in the Modern Digital Audio Environment,” Fielder, Louis D., JAES Volume 43 Issue 5 pp. 322-339; May 1995
Note that both papers are Journal of AES which means they were "peer reviewed." If peer reviewed means folks can write exaggeration then we might as well never reference anything at AES.
If you have disagreement with the research, by all means, make your case with data and references as I have done. Saying, "nah, nah, nah" is not an answer. I could claim earth is flat the same way. That doesn't make it right.
As to the specific references to two ears and a brain, think of this simple thought experiment. Think back to hearing your loved ones in different rooms in your house. Did they sound radically different? I bet not. They had the same familiar voice no matter if they were in your living room or bathroom. If you measure with a microphone, her voice would measure very differently. The room reflections are wildly different causing different frequency response and amplitudes which the meter "faithfully" records. Problem is, it is all a lie. As I just mentioned, what you perceive is that your loved one's voice is the same. Not what the meter is telling you.
The confusion comes from the fact that there are two parts to human hearing:
1. Detecting the sound. This is determined by the anatomy of your ear, face, etc.
2. Perceiving the sound. This is the cognitive, i.e. thinking part of your brain which kicks in to make sense out of incredible amount of data being transmitted by the ear. You would go crazy if you actually "heard" all that comes in. The brain performs analysis and decided what is useful, what is not. In the case of your loved one, the brain has learned that the room reflections are "constant" and lack useful information so it tunes them out. And focuses on what your loved one is saying which is the important thing you are interested in hearing.
If you want to read more, I have written an article on that too
. You will likely blow a second fuse after reading it in how it tears apart your conceptions of audio and room acoustics: http://www.madronadigital.com/Librar...flections.html
You ask about the meter being more accurate. What is accuracy? That some electrical signal resulted in some numerical value? Why would I care about that? What I care is measurements that tell me what I am hearing. A 3 db increase in power means you have twice as much power. The meter will confirm this. Except that to actually perceive twice the loudness you need 10 db. So the db numbers are clearly a "lie."
As for video vs audio, let's not at all go there. Video is designed "right." It has a reference that we can compare all of our playback systems. We indeed point a meter and get what was recorded to match what is being played. The two systems are then the same and we are seeing (in theory anyway) what the talent did when approving said content in front of the colorist.
Audio in comparison is a busted mess. You hear guitar being played in your system. There is no way that is sounding the same as the guitar being played live. Even if it did, you cannot prove that. This is why we have so many debates in audio that don't get resolved. Ultimately you can't prove which system is truer to the source. We could flip a coin and fix this by recording metadata that would characterize the recording and match it in playback. But it is not being done.
It is because of the standards in video that we get to use the colorimeter because that is what was used to calibrate the recording system. By using the same tool we can (in theory again) match our playback system to recording. An SPL meter is a joke when applied in audio. Other than its use for movie levels where we have that standard (sadly only level and nothing else), and measuring frequencies below transition to plot our frequency response, it has little to no other use. You better not use it above a few hundred hertz or else, you would be violating psychoacoustics.
Finally as to “two ears and a brain” being better than a meter, I wish I was smart enough to have invented that but I am not. Here is the reference in my article:
By the way, much of this was probably intuitively obvious as you noticed how quiet your room was despite the high SPL numbers shown on the meter. As Dr. Toole, one of the top experts in acoustics and speaker design is fond of saying, “two ears and a brain are much more analytical than a microphone and a meter!” Indeed, your ears told the truth better than the measurement device.
Dr. Toole is an incredible authority here since he is the only acoustics expert who started as a psychoacoustics major and researcher. His ability to combine those two fields together with a ton of data ins unrivaled in the industry/research community. You can learn more about audio than a lifetime spent on forums by reading his superb book on the topic: http://www.amazon.com/Sound-Reproduc...ds=floyd+toole
. $43 will make you smarter than just about everyone here who has not read the book
Here is a choice quote on this very topic:
What is missing from this perspective is that two ears and a brain
are far more analytical than an omnidirectional microphone and an analyzer.
The measurement system simply adds up all sounds, from all directions, at all
times, and renders a single curve. A loudspeaker turned to face the wall, after
equalization, should sound like that same loudspeaker facing the listeners. It
doesn’t. There is insufficient data to describe the source and thereby how it
interacts with the room boundaries. Humans have a remarkable ability to separate
a source from the room it is in and offer up detailed descriptions of how
it sounds, even when the room is changed (see Chapter 11). We need measurements
that describe the nature of the source and that provide insight into what
happens in a room.
If you want to practice pseudo science, by all means stomp your feet and say I am wrong based on what you have read on a forum and what made sense to your gut. But if you want to practice real science, expand your knowledge with reading above book and countless other references I provide in these posts and use them to back your views.
Did you run Arny’s test by the way? Please post your results.