The Art Of Listening
Listening to and experiencing an audio environment is a unique and intense multilevel encounter.
Stephen Handel, Professor of Psychology at the University of Tennessee, put it as well as anyone in the preface to his wonderful book: Listening: An Introduction to the Perception of Auditory Events (MIT Press, 1993, ISBN13: 978-0262081795, $62):
"Listening puts me in the world. Listening gives me a sense of emotion, a sense of movement, and a sense of being there that is missing when I am [just] looking. I am more frightened by thunder than by lightning, even though I know that thunder is harmless and lightning is deadly. I feel far more isolation living with ear plugs than living with blinders. Listening is centripetal, it pulls you into the world. Looking is centrifugal, it separates you from the world."
Let's understand precisely what Handel is saying: If the audio system's re-creation capability is working correctly, it can and should pull the listeners into the presentation with the power to make them believe that they are "there," wherever there might be.
To do this, the 'there' must be perceived as real enough to place the listeners in the scene or story with enough strength to make them forget that they are actually sitting someplace else.
The Almost Lost Data
Over the years the industry has used a variety of hardware types and analysis approaches to measure and determine audio system performance. Because these methods produce mostly objective, accurate*, and repeatable data that has no subjective component, we have been trained to rely almost totally on our test equipment to tell us what we are hearing. [* The accuracy of the data gathered by any measurement system is very much dependent on the care and precision taken during the measurement process. Good technology can most certainly produce bad data.]
However, no matter how sophisticated that instrumentation might be, or how expert the operator, none of those systems can (as yet) measure, compile or quantify to the same degree of precision the complex psychoacoustical aspects that are inherent in the way the ear/brain system processes sound.
It is critical to understanding the listening process to recognize that unless your ear/brain system is impaired, 100% of the time that you are awake and aware, your ears are delivering a flood of information to your brain about the kind of space you are in by constantly painting a complex sonic landscape in full 3D, and covering a full 360บ.
In physical spaces such as residential entertainment rooms or motion picture theaters you are receiving input from the complex speaker/room combination about the kind of perceivable acoustical reality that the system is creating in that particular space. But if you just look at the numbers from your measurement systems, you might not recognize how much information you are either ignoring or discarding.
You can look at this disparity by recognizing that if you use only the pure data, you are taking your high-definition full-color 3D 360บ virtual reality and limiting it in every parameter to a less-detailed lower resolution sonic image of the same scene. It's the difference between the late-20th-century TV series Star Trek's holodeck and today's simulation rides and surround gaming experience.
You are not using a good deal of the available information because you have never been trained to listen for it and to exploit the information that is sitting there in plain 'view' (pardon the pun).
Do not misunderstand this point. I am not suggesting that you give up instrumentation and use only the cognitive, psychoacoustical and (to a degree) subjective information.
While that approach will allow you to use very inventive descriptive verbiage, without the scientific information you cannot really use the other data as effectively, and you will have no objective foundation upon which to position the other information. It is crucial to recognize that the approach described below is not a case of either/or.
It is a methodology that combines the recognized and respected instrumentation-generated data and the stuff you were not using, to give you a much more powerful analytical tool in determining the quality and performance of audio systems.
We need to do this because it is the ears (and the listening experience they produce) of your customer that will make the final judgment on you work.
Judging The "Reality Creation Quotient" (RCQ)
How To Do This Efficiently And Accurately
However, I can provide some guidelines and methods to help you get started. I must emphasize that the only way you will become truly proficient is to practice, practice, practice. Only over time can you train your ears and your brain to 'listen' through the system to hear the cues that will tell you what you want to know.
To give you that start, we will explore what you can do to add to your capabilities and offer some basic tips on how to do this. The first and most critical step in building up your ability to use your listening skills is learning how to break down a soundtrack or other source into its component pieces, and understand how they must fit back together to deliver the audio experience with its maximum power and believability.
While you can use almost any recorded sound source to do this, motion-picture soundtracks provide, in our experience, the best sources.
Why Should You Use Soundtracks?
When listening critically to a soundtrack to judge system performance, you must observe the accuracy of the music reproduction and the naturalness of the dialog. These elements are crucial to the overall experience. Your measured data about loudspeaker spectral accuracy, plus a good careful listen to a variety of program material, will give you significant information about how well any system is going to handle these tasks.
The objective is to determine how even is the response and how uncolored is the delivered sound field at the listening positions. Any real problems in those areas will show up almost immediately as a lack of musicality or unnatural-sounding dialog, and should also be evident in your measured data.
Quick-Reference List Of What To Listen For
Accuracy While this can be a highly subjective parameter, the measurements collected on system performance using appropriate tools are the basis for determining if a system is delivering a smooth, even sound field within the listening space. Subjectively it is essential to verify that the speaker system is not producing any output that is not within the original signal (see "Colored/uncolored", below).
Dialog Dialog is the core element of any motion picture presentation. The center-channel speaker delivers almost all of this information. Ensuring that the speech sounds natural and is accurate to the actors'/actresses' actual presentation is essential. They must sound 'real' and not constrained or thin. Dynamic range and clarity are also key parameters to check.
Colored / Uncolored Coloration is caused by the addition of unwanted harmonics or resonances to the original signal. These might be generated by the loudspeaker itself, or the speaker/room combination. You must 'know' what something is supposed to sound like to determine coloration. Listening to your selected test material on a known good system is the best way to establish these benchmarks. [We hear voices in our everyday lives, and recognize when recorded voices sound right. Also, attending concerts of un-amplified acoustic instruments, of any type of music, can provide an excellent natural reference, especially given the consistently high-quality soundtracks on today's movies. DJW]
Naturalness This is a largely subjective parameter. However, if voices or ambiance do not seem 'real' and unforced then they are probably not 'natural,' either.
The best way to use this listening technique is to pick one or two film segments (see below) and listen to them on several systems that you know to be best in class. You need to pick just a few chapters (I recommend no more than two or three 5-6-minute segments) from each film and listen to them repeatedly to establish a benchmark of what they are supposed to sound (and look) like. [Always remember that images distract from critical listening. DJW]
Once you have this benchmark embedded in your brain, you should be able to play those same segments on any system you are testing or calibrating and make an immediate evaluation of that system's performance. This method has been used for decades by live-sound engineers (including your author in a much earlier life), who play a few of their favorite cuts from their "test" CDs every time they set up a system.
This gives them both a feel for how the system is performing within the specific space, and a good indication as to whether the basic system parameters are within spec, plus a quick and easy check to ensure that the hardware is working properly.
It's All In
That space could be a real place such as a cornfield in Iowa, or a totally unknown place (at least to most of us) such as the bridge of a nuclear-powered submarine. The difference between a good system and a great system will show up in how well it re-creates and places these details into the whole sound field.
To illustrate this method we use a number of specific Blu-ray- or DVD based soundtracks. Of course you can choose others to suit your personal preference, but these work extremely well for this purpose.
Start with a blank diagram of a typical 7.1/5.1-channel playback system with boxes for each loudspeaker location. As you play each film clip, first put into those boxes what you hear coming from each source. Then after calibrating the system properly, you should hear what you are supposed to hear from each source. You should note this on another copy of the same form.
Field Of Dreams
If the system is properly set up, all of this information will be there; if not, much of it will be buried and lost positional information, like the fact that the wife/child/swing are all center-left to match the camera shot, will also be smeared and indistinct. This scene lets me determine if the system is properly equalized, delayed and level-balanced, because if it's not, all of this stuff collapses and the ambiance is not created.
Chapter 7 starts in the farmhouse living room with Costner and Amy Madigan discussing if they can keep their farm. The daughter enters the room and tells Costner, "Daddy, there's a man on your lawn" announcing the first appearance of Shoeless Joe Jackson.
Costner gets up and walks across the floor, out onto the porch, across the porch to turn on the three light poles, down the steps across the yard, onto the gravel and then onto the grass of the baseball diamond. Again there is a huge amount of subtle detail like the various sounds Costner's shoes make as they change surfaces, the motion he makes as he walks across the front sound stage, the sharp clicks of the light switches, the squeaky swing of the screen door, and so forth. As in chapter 2, the detail makes the scene real and brings it to life. If you have calibrated and balanced the system properly the soundtrack should pull you right onto that porch and with Costner as he walks out to the diamond. It still sends chills down my spine when it works right, and it should do this for you, too if the system is accurate. In investigating this soundtrack and asking questions of some of the people involved, I was told that there were over 100 sound elements used to make these scenes real, and each has a specific place in space and sound to contribute. If they all mesh correctly you will not want to stop the disc you will fall into the movie which is exactly the goal.
If the system is set up correctly the wing beats slide seamlessly and smoothly from speaker to speaker and the whole ambiance rotates with the onscreen image of the dragon. There's substantial low-frequency content added into the voice, so it also tests your main-system-to-subwoofer splice and subwoofer accuracy and tone. The voice should be solid and very heavy without boominess.
The rain in chapter 6 is a fine test for surround ambiance creation and a system's overall ability to create a sense of 'there', as discussed earlier. Every time I use these scenes, in classes or on jobs, I know if things are working properly because people stop what they are doing and become glued to the movie.
Often there will be a physical 'jerk' or snap in their body language when the stop button is pushed and suddenly their "location" shifts instantly from the picture back to the reality of the room we are in. This tells me that we have successfully re-created the acoustical space intended and that the details are coming through to make everything seem real.
It might be difficult to understand what happens until it happens to you, but when it does you will never look at your systems in the same way again.
I encourage you to experiment and find what works for you, but remember that if you don't disappear into the movie if the listening experience is not centripetal and doesn't pull you in then there are probably things wrong with the acoustical envelope your system is producing that are interfering with your ability to fool the ear/brain into believing it is someplace else.
There is an element of art and magic to this process, and once you get it to work for you, it will allow you to really showcase your systems to their utmost ability. Enjoy the ride!
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