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[教程] 可视化压缩的秘密

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可视化压缩的秘密


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本帖最后由 mimiD 于 18-9-8 21:20 编辑

| By Thomas Brett |
Introduction:
Without a doubt, the studio tool which people seem to have the most trouble getting their heads around when first starting out is Compression.
The most common reason for this, in my opinion, is the fact that the whole concept is often taught poorly/in the wrong way to begin with!
In this week’s URM Blog, rather than rambling on in vain about some abstract terms that most beginners don’t understand in the first place (as most tutors in “good” audio schools seem to do…), I’ll attempt to show you exactly how a compressor is affecting a signal via some easy-to-comprehend visual examples.

介绍:
毫无疑问,人们似乎最难开始使用的工具是压缩器。
在我看来,最常见的原因是整个概念通常教得很差/以错误的方式开始!
在本周的URM博客中,而不是漫无目的地谈论大多数初学者一开始并不理解的抽象术语(正如“好”音频学校中的大多数导师似乎......),我会试着通过一些易于理解的视觉示例告诉你,压缩器如何影响信号。

VISUALISING COMPRESSION 可视化压缩


Before we dive in head first, it’s important that you have a general working understanding of the terminology, and what we’re trying to achieve with the use of compression in the first place:
在我们首先深入研究之前,重要的是您要对术语有基本的了解,以及我们尝试使用压缩实现的目标:

Compression, In Basic Terms… 压缩,基本条款......
At it’s core, “compression” does exactly what it says on the tin when talked about in the context of audio: It reduces the distance between the quietest and loudest parts (the dynamic range) of an audio signal, resulting in a more consistent overall volume.
在它的核心里,“压缩”完全与它在音频环境中所说的一样:它减少了音频信号中最安静和最响亮的部分之间的距离(动态范围),从而使整体更加统一。



Beyond this primary functionality, the various controls which are available on a given compressor’s user interface simply allow us to shape how said “reduction” takes place (to a certain extent):
除了这个主要功能之外,给定压缩器的用户界面上可用的各种控件只允许我们塑造所述“减少”的发生方式(在一定程度上):

Threshold/Input: The minimum level at which compression/gain reduction starts to occur. (The crimson line in the graphics below)
阈值/输入:压缩/增益减少开始发生的最低水平。 (下图中的深红色线)
Ratio: The severity of the compression that’s being applied to the signal. Ex. A 4:1 ratio means that for every 4dB of level that goes above the threshold, only 1dB of audio will be allowed through (3dB of compression will occur).
比率:应用于信号的压缩的程度。防爆。 4:1比率意味着对于超过阈值的每4dB电平,将允许仅通过1dB的音频(将发生3dB压缩)。

4:1 Ratio – BEFORE COMPRESSION 压缩前


4:1 Ratio – AFTER COMPRESSION 压缩后


Attack: How long it takes for the compressor to “catch up” to the audio signal which has gone above the threshold / How long the compressor waits before clamping down.
起始时间:压缩器需要多长时间“赶上”超过阈值的压缩信号/压缩机在压缩之前等待多长时间。


Image: The resulting peak from a 1kHz sine-wave being compressed by 10dB through a Waves CLA-2A Compressor (The 2A has an average attack time of 10ms)

图像:1kHz正弦波通过Waves CLA-2A压缩器 压缩10dB产生的峰值(2A的平均起始时间为10ms)

Release: How long it takes for the compressor to “let go” of the compressed audio signal after it’s gone back below the threshold / How long the compressor waits before returning the signal to its’ uncompressed state.
释放:压缩器在压缩音频信号回到阈值以下之后 “松开”压缩音频信号 需要多长时间/ 压缩器在将信号返回到“未压缩”状态之前等待多长时间。



Image: The resulting release curve from a 1kHz sine-wave being compressed by 5dB and then suddenly dropped below the compressor threshold, triggering the release.

图像:由1kHz正弦波产生的释放曲线被压缩5d​​B,然后突然降至压缩机阈值以下,触发释放。

有坛友反映作者对于起始和释放时间的“误解”,特地贴上中文百科以免更多误解。

启动时间(Attack time):决定了当电平峰值超过阈值多长时间后开始进行压缩。如果启动时间设置得很短,甚至为0,那么一旦电平超过了阈值,压缩器就会开始工作。这样,可能会引起声音忽大忽小的情况发生。因此适当地设置启动时间是很重要的,使启动时间大于那些偶尔超过阈值的电平的时间即可避免这种情况的发生。

释放时间(Releasetime):决定了当电平峰值低于阈值多长时间后停止压缩工作。如果释放时间过短,当电平峰值低于阈值时,压缩器就会立刻停止压缩。这也可能会让声音出现“锵锵”声,所以适当地调节释放时间也是很重要的。

Makeup Gain/Output: This is a volume knob for turning your overall signal back up after compression. That simple!
补偿增益/输出:这是一个音量旋钮,用于在压缩后恢复整体信号。那很简单!

NOTE: Most compressors just have a regular-old output/volume knob for matching your input and output levels by ear, but some of them come with fancy “auto make-up gain” controls which attempt to do the job for you. Either way, they’re both serving the same basic purpose.
注意:大多数压缩器只有一个常规的输出/音量旋钮,可以通过耳朵匹配您的输入和输出电平,但其中一些还带有花哨的“自动补偿增益”控制,可以为您完成工作。无论哪种方式,他们都服务于相同的基本目的。

Practical Compression 实际压缩
Once you’re past the initial “understanding what the heck this thing does” phase, you’ll eventually learn to ignore the numbers and come up with intuitive ways of utilising compressors in a much more practical “problem solving” manner.
一旦你超越了最初的“了解这件事做什么”的阶段,你最终会学会忽略这些数字,并以更加实际的“问题解决”方式提出直观的方式来利用压缩机。

Here are a few practical compression examples off the top of my head:
Gentle Limiting For Transient Reduction: Come across a piano which sounds particularly tacky or brittle on the front-end? Use a limiter with a super fast attack/release to chop off those annoying transients without altering the overall dynamics of the instrument!
以下是一些实用的压缩示例:
用微妙的限制做瞬态还原:遇到一个钢琴,前端听起来特别俗气或脆弱?使用具有超快速起始时间/释放的限制器来切断那些恼人的瞬态而不会改变乐器的整体动态!

Tacky Keys – Before Waves’ L1 Limiting 限制前


IMAGE: Notice the sharp attack transients at the beginning of each audio blob.

图像:注意每个音频斑点开头的尖锐起始时间瞬态。

Tacky Keys – Rendered With 6dB of Waves’ L1 Limiting 给予6db限制


IMAGE: Notice how the transients have been smoothed out by the limiter, while the rest of the audio remains untouched.

图像:注意限制器如何平滑瞬态,而其余的音频保持不变。

Quick Release For Extra Room Ambience: Looking to thicken up your drum room tracks and give them some nice depth and “washiness”? Try using some fast attack / fast release 1176-style compression to reduce the initial drum hits in the mics and bring up the level of the room sustain.
对于额外的房间氛围做快速释放:期待加厚您的鼓房间轨道,并给他们一些很好的深度和“洗涤”?尝试使用一些快速起始时间/快速释放1176式压缩来减少麦克风中的初始鼓点击并提高房间维持水平。

Fast Attack / Fast Release 1176 Style Compression On A Kick Drum

在底鼓上做 快速起始时间/快速释放 1176型压缩


IMAGE: This kick drum was compressed by 10dB with an 1176 style compressor set to a fast attack/release. Notice how the direct “shell sustain” portion of the kick is still around the same overall volume (with a reduced attack transient due to the fast-attack compression), while the ambience/room sound/reverb of the kick that was below the compressor’s threshold is greatly increased in volume after the make-up gain was applied.

图像:这个底鼓压缩了10dB,1176型压缩机设置为快速起始时间/释放。请注意,底鼓的直接“外壳维持”部分仍然是在相同的整体音量周围(由于快速起始时间压缩而减少了起始时间瞬态),同时在压缩机下方的空间/房间声音/混响效果低于压缩机应用补偿增益后,阈值的体积会大大增加。

NOTE: In cases where there isn’t much room sound in the signal to begin with (Ex. A vocal which was recorded in a great isolation booth), using a quick release will really help towards bringing up the the volume of the intimate details in the signal (such as mouth noises & consonants) and really help level-out the performance. On the flipside, ”fast-release compressing” a vocal track which has a lot of bad room resonance baked into the sound will most likely accentuate the problem, making it even worse.
注意:如果开始时信号中的房间声音不大(例如,在一个很好的隔离室录制的声乐),使用快速释放将真正有助于提高私密细节的音量在信号中(如嘴巴噪音和辅音),真的有助于提升表现。另一方面,“快速释放压缩”声音轨道会在声音中产生很多不良的房间共鸣,这很可能会加剧问题,使其更加糟糕。

Slow Attack / Fast Release For “In Your Face” Punch: Using a slower attack setting allows for the initial “attack” transient of a sound to pass through the compressor untouched, resulting in an increased sense of aggression and impact when the processed signal is volume-matched to the uncompressed signal using the makeup-gain control.
慢速起始时间/快速释放“在你的脸上”冲击:使用较慢的起始时间设置允许声音的初始“起始时间”瞬态不受影响地通过压缩器,当处理的信号是时,导致侵略感和冲击感增强使用补偿增益控制与未压缩信号进行音量匹配。

Smack Attack – Slow Attack SSL Compression On A Snare

拍击音头 - 在小军鼓上做慢速起始时间SSL压缩


Image: On the slow-attack setting, the SSL E-Channel compressor waits for around 30ms before acting on my fake sine-wave snare, resulting in a giant transient “click” when compressed by 6dB and volume matched to the unprocessed signal.

图像:在慢速起始时间设置中,SSL电子通道压缩器等待大约30ms,然后对我的假正弦波小军鼓进行操作,当压缩6dB并且音量与未处理信号匹配时,导致巨大的瞬态“咔哒”声。

Limiting To Even-Out Sustained Instruments: Heavily sustained instruments such as pads, synths, keys, ambient swells and sub-basses don’t have much to offer in the area of transients, and are often very gradual in the way they rise & fall in volume. These inherent characteristics make them excellent candidates for limiting, as there won’t be any sudden jumps in volume to mess with the attack/release cycle of the compressor, or cause any annoying “fast release” distortion artifacts.
限制均匀持续的乐器:在瞬态区域中,Pad,合成器,Keys,氛围音和低音等重度持续的乐器并没有提供多少瞬态区域,并且它们的音量上升和下降方式通常非常缓慢。这些固有特性使它们成为限制的理想选择,因为压缩机的起始时间/释放周期不会有任何突然的音量跳跃,或导致任何恼人的“快速释放”失真伪像。

L1 To Oblivion – Evening Out A Highly Dynamic Signal

L1湮灭 - 甚至出现了一个高度动态的信号


IMAGE: In this drastic example I’ve put together to prove my point, notice how the super-dynamic and random signal I’ve generated via volume automation gets completely obliterated or “dynamically flatlined” by the heavy-handed “brickwall” limiting of the Waves’ L1 limiter & some make-up gain.

图片:在这个激烈的例子中,我总结了一下来证明我的观点,注意我通过体积自动化生成的超级动态和随机信号如何被严厉的“砖墙”限制完全消除或“动态平坦” Waves的L1限制器和一些补偿增益。

NOTE: There are obviously a lot of additional scenarios and examples I could give to further demonstrate the way compression applies to audio, but I think you get the point by now…
注意:显然有很多其他场景和示例我可以给出进一步演示压缩应用于音频的方式,但我认为你现在明白了......

CONCLUSION:
Compression is awesome… And not nearly as daunting as you’d originally think once you buckle-down and really get a practical grasp of it!
the best piece of final advice I can possibly give you in regards to learning compression is to stop worrying about the numbers.
Remember, everything is source dependant, so stop trying to blindly copy other people’s compression settings and simply get on with using your own ears to determine the right course of action!
结论:
压缩是非常棒的...并且不像你原先想的那样令人畏惧,一旦你扣紧并真正掌握了它!
我可能会给你关于学习压缩的最佳建议是停止担心这些数字。
请记住,一切都取决于源文件,所以不要试图盲目地复制其他人的压缩设置,只需继续使用自己的耳朵来确定正确的行动方案!

扩展视频:P1 https://www.你吐吧.com/watch?v=Eo1O61Pi79o
P2 https://www.你吐吧.com/watch?v=X85-13qiofM

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观众反应

12385
感谢分享。。。。。

2299
谢谢老师的翻译,然而这篇文章关于Attack和Release错了,日常解释错误,或者说不全面,应该是作者为了便于初学者理解故意简化了。

100
Erilan 发表于 18-9-8 20:48
谢谢老师的翻译,然而这篇文章关于Attack和Release错了,日常解释错误,或者说不全面,应该是作者为了便于 ...

你来解释解释

2280
谢谢

544
Erilan 发表于 18-9-8 20:48
谢谢老师的翻译,然而这篇文章关于Attack和Release错了,日常解释错误,或者说不全面,应该是作者为了便于 ...

我从开始学混音到现在,对于Attack和Release也就接触过这么一种解释,但是总听说有另外一种解释……我不知道另外的解释是啥样的?可否详细说说?

65
还是有问题,最明显的染色类的压缩不是你到不到阀值都开始工作的,attack针对单纯的压缩比开始计算的位置,不是整个压缩器

2299
qzhsjz 发表于 18-9-8 23:14
我从开始学混音到现在,对于Attack和Release也就接触过这么一种解释,但是总听说有另外一种解释……我不 ...

Attack和Release表示的是GR的变化速度。

2777
本帖最后由 yousing 于 18-9-9 01:58 编辑

记得我在某个帖子与人讨论过Attack和Release这俩玩意儿,那帖子我一时找不到了,也大致是质疑这个概念理解的问题···也是说应该从GR角度去理解、解释···具体我记不太清楚了···

我觉得,仅仅以说“Attack和Release表示的是GR的变化速度”是有问题的,Attack和Release只在触发点和释放点,以及两者的时间叠置区对压缩的GR产生影响,已经进入持续压缩状态下的GR速度是由压缩比、阈值和音乐动态本身决定的···当被压缩音频的电平连续处于阈值之上,且被压缩音频动态起伏变化依然不小,这一区间GR的变化速度与Attack和Release应该没有半毛钱的关系···

但是,如果表述陈"Attack时间是从触发点开始压缩,GR从无压缩量上升到设定状态下的满压缩量所需的时间","Release时间是从触发点开始释放压缩,GR从设定状态下的满压缩量进行到无压缩量所需的时间",那或许就没有问题了···这样看起来,跟一楼的意思一样咯···至少这句可以直接理解没问题  “释放:压缩器在压缩音频信号回到阈值以下之后 “松开”压缩音频信号 需要多长时间/ 压缩器在将信号返回到“未压缩”状态之前等待多长时间。

至于“Attack: How long it takes for the compressor to “catch up” to the audio signal which has gone above the threshold / How long the compressor waits before clamping down.”······我英语不好,但我感觉直译不好理解,前半句类似以一种比喻方式在描述: “catch up” 是“跟上”的意思,怎么样才算跟上呢,就是达到设置状态下的满压缩量,或者说是稳定压缩量,这就类似于,你在前面走,我在后面追,目标是与你保持5米距离,然后进入稳定同步状态,停止追赶状态···,我从静止开始加速,20米、15米、10米、8米逐步缩短到既定的5米,这个过程所需的时间,就是Attack!后半句很好理解,就是压缩进入设置状态的满压缩量【也就是被参数钳制状态,不会继续变化的稳定状态】之前,需要多长时间~···,唉···绕死了···就是一个意思,换角度说~!

说到这里,发现其实老外说的就是GR,只是这个GR是与触发点和释放点相关的GR···没问题····!





100
yousing 发表于 18-9-9 00:50
记得我在某个帖子与人讨论过Attack和Release这俩玩意儿,那帖子我一时找不到了,也大致是质疑这个概念理解 ...

这样绕来绕去的,很OK

544
本帖最后由 qzhsjz 于 18-9-9 10:56 编辑
Erilan 发表于 18-9-9 00:00
Attack和Release表示的是GR的变化速度。

这篇文章的配图里面Before和After的差值不就是GR随时间变化的图像吗?
这两种表述一个侧重于瞬态,一个侧重于结果,但是应该都是等价的表述吧?


2777
本帖最后由 yousing 于 18-9-10 14:21 编辑

又或者可以这样表述,Attack时间是指的触发压缩之后,实际压缩Ratio从1:1上升到设定的 A:1【A>1】所需的时间···Release正好相反,释放触发后,实际压缩Ratio从设定的 A:1【A>1】回落到1:1所需的时间···


这两个参数描述的实际上是压缩触发的起始处和结束处,RATIO参数的提升和回落的所需时间···比如,设定压缩比为4:1,那么描述的就是压缩比从1:1变化到4:1或者从4:1恢复到1:1的所需时间~```

所以,我现在觉得昨晚说的可能还不如这样的描述简单准确,Attack和Release,说的就是RATIO的上升和回落速度【也就是所需时间】,而用GR或者其他来描述都挺绕的····

另外,关于有低于阈值的音频部分被压缩,其实也很好理解,当压缩被触发释放,音频峰值瞬间落到阈值以下,而压缩依然在压缩,但已处于释放过程中【也就是从设定压缩比回落到1:1】这是需要时间的,只要是释放这个时间覆盖的音频区,即使都在阈值之下,依然有可能被压缩到······这不是颠覆压缩理论,而是压缩理论的现实体现···



观众反应

539
翻译有点毛病,我是看原文的。
说实话感觉现代混音可以把动态分为宏观与微观两部分,作为微观的瞬态大部分可以交由瞬态塑型的插件去处理。

100
Ryusa 发表于 18-9-9 12:37
翻译有点毛病,我是看原文的。
说实话感觉现代混音可以把动态分为宏观与微观两部分,作为微观的瞬态大部分 ...

哪里翻译有毛病,趁还能改

102
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