解析汽车音响的声场与定位

tenchi

刚刚看到一个很好文章：

你的音场是如何？

You are in the music, like the drummer at the rear of the concert stage and listening to the concert.


You sit a few rows away with the sound stage in front of you, sit in a comfortable seat listening to the concert stage away from you.





等我等空有时间翻译+消化后再写写看。。。

莫哈麻

刚刚看到一个很好文章：

你的音场是如何？

You are in the music, like the drummer at the rear of  ...
tenchi 发表于 19-2-2012 03:49 PM

这两张照片很有意思....谢谢分享！！

tenchi

回复 82# 莫哈麻


    没有加分一下

tenchi

Depth of Image

3-D，是需要2只眼睛看才可以看到，如果单眼是看不到什么3-D效果的，声音也是一样的道理。
我们的大脑和耳朵是根据声音的 level, direction, time 和 frequency content 来分析，然后形成一个3-D的“音乐”。

录音：

By "collecting" the total sound at one single point with a stereo microphone -that is, a microphone with its capsules as close together as possible -we obtain a strict relation between the direct sound and the reflected sound (the diffused sound field), and this gives our brain and auditory system important information for building up an illusion of "reality" - the concert hall, the church or the jazz club. It is also very important for the direct and the reflected sound to have an exact acoustic connection with the sound-waves from each instrument. In traditional recording studios, there is, basically, one microphone (or sometimes even more) per instrument, and these are then mixed together electrically. This is not real stereo, it is just panned mono.
Since, moreover, the microphones are usually placed very close to each instrument in an acoustically dead studio, all one gets is the direct sound of the instrument, and so artificial reverberation has to be "added on" electrically afterwards.

tenchi

Timbre (音色）

By timbre we mean the specific character of an acoustic musical instrument - meaning, for example, what makes it possible for us to tell one instrument from another. The timbre of a musical instrument is a combination of its significant spectral distribution, i.e. the relation between notes and their harmonics and each relative level and frequency distribution, and last but not least, the way in which the sound-waves radiate from the body of the instrument.

All our acoustic instruments are designed to be played in some form of concert hall, i.e. in a place where you hear both the direct sound of the instrument and the reverberation of the environment. If, like Opus 3, you are aiming for as natural an instrumental timbre as possible, it is vitally important that acoustic instruments can also be recorded in the type of surroundings they were originally designed to be played in, but also with longer microphone distances, so as also to capture the sound radiating from the whole sounding body of the instrument. The short microphone distances normally used also make the timbre unnatural, and so it has to be "restored" artificially, using various equalizers etc. We mustn't forget that when our acoustic musical instruments were created, a long time ago, neither electricity, microphones or recording studios existed !

tenchi

Dynamic （动态）

The dynamic range of a musical instrument is the difference between the loudest and the softest sound level it is capable of producing. Like timbre, the dynamics of a musical instrument depend, not only on how it is built but also on how it is used by the composer and performer. Dynamics in this sense are used to create a large number and variety of musical effects, changes of emotion, mood and expression etc., etc. The dynamic properties of a musical instrument are also very much affected by the way in which it is recorded. The short microphone distances used for multi-microphone recording in traditional studios also exaggerate the recorded dynamics. Just like timbre, the dynamic balance then has to be artificially "restored", using compressors, limiters and so on.

tenchi

Tonality （音调）

Commonly referred to as tonal accuracy and spectral balance, tonality is that quality of a system that gives the musical instruments their natural sound. If a saxophone is played, for example, it sounds exactly like a real saxophone, and you can tell it is not a trombone, french horn, tuba, or any other brass instrument. Likewise, any instrument has it's own characteristic sound, and a system with good tonality will allow the listener to differentiate the instruments being played. According to the Official IASCA (International Auto Sound Challenge Association) rulebook of competition, Tonal Accuracy and Spectral Balance is a combination of six characteristics---loudness, pitch, timbre, modulation, duration, and attack and decay.
Brief definition:
1) loudness-the magnitude of the sound.
2) pitch-the quality of a sound that determines it's position on a musical scale.
4) timbre-harmonics that give a sound it's sonic signature.
5) modulation-changes in amplitude, phase, or frequency that occur in a sound.
6) duration-length of time a sound is heard.
7) attack and decay-the time it takes a sound to build-up(attack) and die-down(decay).

tenchi

Listening Position relative to the perceived sound stage （舞台相对位置）

Basically, in a concert, the musicians are on a stage in front of you, and likely they are well in front of you as you'll be sitting in the audience. Good SQ systems will give the illusion of this same perceived stage being well in front of you. Systems with poor "listening positions" will make you feel like the musicians are in your face, around you rather than in front of you, or even worse, behind you. Remember the goal is to simulate watching and listening to a live performance, and as such there are no musicians beside or behind you. The best systems will give you the impression of the stage being a considerable distance in front of you, as if you were sitting a few rows back in the audience.

tenchi

Stage Width （舞台的宽度）

How wide is the sound stage? Car interiors are horrible for good sound reproduction. However, a wide sound stage is an important factor. Bad systems will have almost no width, sounding as if only a center channel speaker is playing. Better systems have well defined left and right stage boundaries, but these boundaries will stay well within the interior of the vehicle.

The best systems will have stage boundaries, which extend BEYOND the physical area of the vehicle, with noticeable sounds that seem to emanate from a location outside the car (like from the side mirrors). The key to getting good width is to do so WITHOUT affecting center imaging, creating a "sonic hole" in the middle of the stage.  

tenchi

Ambiance （氛围）

Ambiance is that phenomenon that gives you a sense of space around an instrument. Many people confuse ambiance with artificial "surround-sound" echoes meant to add the illusion of music all around you. Every recording contains ambiance of some sort, be it a sense of "air" around the instrument or the "sound" of the room the track was recorded in. Using reference recordings where the actual recording room characteristics are known ahead of time, SQ judges can score ambiance based on whether the performance "seems" to be played from inside this actual room. For example, there is a track on the '97 IASCA SQ competition CD that was recorded by a single microphone at a level of approximately 20' above the stage, INSIDE a large auditorium. With proper ambiance, it should seem like you are in that large auditorium when you listen to this track. THAT is proper ambiance, not artificial ambiance. Tuning and speaker quality have the most impact on ambiance, followed closely by controlling sonic reflections and resonations in the vehicle and speaker placement with proper x/o selection. Some people use ambiently tuned rear fill speakers to try to accomplish this aspect, but in a properly designed and tuned system, rear fill is NOT necessary to acquire excellent ambiance.

tenchi

Imaging （音影像）

The sound stage should be looked at in 5 separate sections: Left, left center, center, right center, and right. These are the most common locations on the stage used to evaluate the imaging characteristics of the car. By using reference material, the judges know exactly where the different instruments should be "located" on the stage. A system that images well will have well-defined and focused instruments located exactly where they should be on the sound stage. These images will not wander from their locations, and you could easily close your eyes and point to where each instrument actually is. Many systems exhibit frequency-dependant imaging where as the frequency changes in pitch or scale, the image will move accordingly. This is not good imaging. Likewise, some systems have good left and right imaging, but fail to get a center-stage focus at all. To many, the center image is the most important location on the stage, and it is easy to tell which cars have good centers and which don't. Speaker placement, path length differences, and proper equalization vastly affect imaging, and to a lesser degree, resonations, reflections, standing waves, and uneven interior surfaces play a role in the imaging characteristics of a system.

tenchi

Sound Linearity （声音的线性）

How well balanced does the system sound at low, moderate, and high volume? A system with good linearity will sound equally balanced at all three loudness levels, remaining accurate tonally and free of distortion of any kind. This depends mainly on proper gain settings and equalizer tuning, though other factors can possibly affect it.

Absence of noise （没有噪音）

A good SQ system will be a symbience of many factors coming together to provide a performance free of unwanted noises such as speaker pops, alternator whine, ground loop noise, additional noise floor in the form of extra hiss, on/off thumps or pops, and any other form of unwanted noises. All recordings exhibit a noise floor in the background, It is a byproduct of the recording process that cannot be overlooked, and for this reason, only the noise level present in the original recording will be acceptable.

tenchi

Dynamic Impact （动态冲击）

A superior system should be capable of reproducing the proper "feel" of the music. We need to consider the fact that music has Two dimensions---That which we hear, and that which we feel. If we were to go to a rock concert, sitting front and center, and the drummer decides to go-off on an improve solo while the rest of the band grabs a cold one and some ho-hoes, we are treated to a barrage of dynamic percussion sounds. When facing the stage, we feel the sound waves both in our chest and abdomen as well as on our skin. The bass drum obviously will be the most prominent, however the toms, snare, and even hard cymbal strikes can be felt, and felt easily if the guy is REALLY going -- We can even plug our ears to make this effect more pronounced. Sound is emitted in waves. These waves possess energy levels that are dependent on amplitude (loudness) and the proximity of the listener to the source, thus, we can feel the sound waves as they interact with the touch-receptors in our bodies. Ever flinch or blink upon hearing an abrupt, loud sound? The best car systems are capable of re-creating this sense of dynamics, as it should be "felt" live. And they should do so without feeling percussive waves emanating from rear mounted subs, making us hear the bass player up front, but he feels like he is behind us at the concession stand getting a sausage dog or something. NOT good.

zacisme

谢谢分享，借转

tenchi

回复 94# zacisme


    拿去吧。。。我也懒惰翻译了

wcsian80

回复  zacisme


    拿去吧。。。我也懒惰翻译了
tenchi 发表于 19-2-2012 05:10 PM

    经验老到。。。。。。。。谢谢分享。。。。。

飞剑客

留个脚印得空来慢慢爬。

莫哈麻

回复  莫哈麻


     没有加分一下
tenchi 发表于 19-2-2012 04:20 PM

   真对不起你..混了这么久也还没这个"权限"咧！请你原谅...

tenchi

回复 98# 莫哈麻


    对不起，我错怪你了