电影声音混音四大要点：增益、压缩、均衡、混响

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There are a few misconceptions when it comes to what sound design for film is, so let’s get that out of the way first…
•Sound design is not about assembling neat effects, loud gunshots or using a car crash SFX for every bang or crash in your film.
•It is not about having the loudest film.

Sound design is a process of experimentation to create an audio environment that supports the on-screen action and engages the audience. The true sound designer is constantly listening, learning and experimenting.


扎实可靠的声音设计对一部电影的成功来说至关重要。所以在电影项目中，你该采用怎样的工作流程来创造最好的声音体验？
说到电影声音设计是什么，让我们先来把那些错误的观念厘清：
声音设计，不是把那些整理好的音效（比如枪声）给拼凑起来，也不是把撞车的音效填充到电影里每一个冲撞处。
声音设计，也不是把声音弄得尽可能地大。
声音设计是一个不断试验的过程，用声音创造的环境来配合画面，以此吸引观众。真正的声音设计师总是在不断倾听、学习和试验。


Getting a good mix starts with clean and healthy signals from your sound recordist and boom operator. The dialogue to your film is an essential part of what’s going to translate the pictures to your audience in an emotional direction.

So let’s dive in and explore the principals and techniques of obtaining a good mix for a film:
•Gain staging and Volume
•Compression
•EQ
•Reverb

Gain Staging And Volume

Proper gain staging is important to the fidelity and cohesiveness of your mix. As previously stated, obtaining clean and healthy signals for each track is perhaps the most important part of structuring a mix; as every decision you make from here on out is directly affected by your choices in gain staging.

As a quick aside, it’s important to capture wild tracks on-set when possible (audio intended to be synchronized later on). This will save you from a great deal of ADR in post production (a few extra minutes on set could save you countless hours later).

As you structure your mix, it’s imperative to create sonic depth for the picture. This is done by adjusting and fine-tuning each track’s dB control; creating a sonically rich and diverse atmosphere. You can further create depth and separation in your mix with the addition of reverb sends, but we’ll get to that later. This is where your mix should start to shine; before any compression, EQ or reverb effects have been used.

You generally want your master channel to be peaking around -15dB to -12dB in it’s loudest moments, as it’s important to leave plenty of headroom for mastering. Generally speaking, it’s better to reduce the volume of all the other tracks, rather than boost any one volume. Don’t be afraid to drastically reduce the volume of a track only to gradually bring it up again to find that “pocket” where it belongs. Personally, I find this method much easier than reducing the track’s dB starting at a high volume.

Compression

Applying compression to your dialogue tracks, as well as the rest of your mix, tends to be a subjective matter. So let’s explore that for a moment…

Most every engineer uses compression; with a few carving themselves into this niche (in what has become popular over the years). Compression, gating and expansion all represent the dynamics family of processors by altering the dynamic range of your signal. When squashing your signal into a narrowed dynamic range, the audio is better controlled: it will fit into your mix easier and appear to sound more full.





从你的现场录音师（Sound Recordist）和吊杆员（Boom Operator）那儿拿到高质量的录音素材，是做好混音的第一步。电影中的对白是非常重要的部分，它在情感上向观众传达了画面上正在发生着什么。
首先了解一下电影混音中的几个原则和技术手段：
增益层次（Gain Staging）和音量（Volume）
压缩（Compression）
均衡（EQ）
混响（Reverb）
（译者注：对于音乐混音来说，这四点同样是非常重要的基本概念。三大类基本效果处理器Comp、EQ、Reverb，增益和响度是影响混音质量和最终效果的重要因素。）

增益层次和音量
良好的增益管理是电影混音中真实感（Fidelity）和统一感（Cohesiveness）的重要保证。在一开始构建混音工程时很重要的一步，就是保证每一轨上的声音都是干净和健康的（Clean and Healthy）。自此开始，你做的每一个决定都会直接影响到在增益管理中的选择和操作。
首先说个题外话，但也是非常重要的，在一开始尽可能把各种素材轨道都安排好，因为之后音频文件将要进行同步。这步操作会在后期大量ADR（译者注：Automatic Dialogue Replacement，即后期对白配音）工作时帮你节省不少时间。
当你在混音时，一定要记住根据画面创造声音的深度。（译者注：深度！同声场宽度相比较，深度往往会被忽视。音量是调节声音远近的主要手段，除此之外，均衡和混响也有调整深度的作用。）通过调节和精细调整每一轨道的dB值，可以创造一个声音丰富且多变的环境。你还可以通过调节混响发送轨道等来做进一步的处理，当然这得在之后再做。在加入压缩、均衡和混响等效果之前，我们首先就应该把混音做到整体协调。（译者注：非常重要！在加入各种效果处理器之前，最好是先只用调节增益、声像的手段把混音的结构架起来。不要把各种问题都留给插件去解决，更应该把插件看做是一种混音上的“粘合剂”。）
Most can attest to a threshold ratio somewhere between 2:1 and 6:1 with the attack and release set to fairly fast response times. Though again, there are no rules here. It is best to use one’s better judgement, and most importantly your ears, when determining how much compression to use.

If you have a dialogue track that has a fair amount of ambience noise that you cannot eradicate, you don’t want to use much compression. Because the compressor is “leveling out” the signal, all of that background noise will be boosted to an uncomfortably high noise floor. Yet another reason why it’s very important to have clean dialogue tracks from the get-go.

EQ

Before you begin equalizing your dialogue, soundtrack, or the entire mix, there are a few things to keep in mind about frequency ranges. To avoid a muddy mix, it’s important that each track’s sonic range of frequency is balanced to allow all audio components enough frequency space to breathe. See the image below for a more visual explanation (click for larger view):
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压缩
给混音中对白和其他轨道等加压缩器往往是一件非常主观的事。所以我们就先花点时间解释一下。
几乎每一位音频工程师都使用压缩，通过一些细微的参数调节来迎合大众对于压缩器的热衷，近几年还愈演愈烈。（译者注：原作者似乎又讽刺之意。压缩真是一门大学问，细微的参数调节就能分辨出差别，是需要何等的功力和好耳朵。）压缩、门限和扩展，都属于动态处理器，它们都能调节音频信号的动态范围。当你压缩了信号的动态范围时，它就更容易被控制：声音会变得饱满，并能更好地融合在混音中。


大多数情况下，压缩比会设置在2:1和6:1之间，起动和释放时间也相对较快。但还是那句话，参数调节没有准则可据。最好的方法还是相信自己的判断，靠耳朵来决定到底需要多少的压缩。
如果你的对白轨中有相当多的不能去除的环境噪音，那就不能使用太多的压缩。因为压缩器会将信号进行“平均化”（Leveling Out），这会提升底噪电平到一个明显可闻且非常恼人的程度。这也恰恰解释了，为什么从一开始就要获得干净的对白轨道是何等的重要。

均衡
在你开始对各条音轨或是整个混音进行均衡操作前，关于频率范围有几点需要牢记在心。为了避免混浊（Muddy）的混音，对每一条音轨进行频率平衡调整是非常重要的，以此来保证任何一个音响元素都能足够的频率空间来展现。下图是一张来自 Waterline Media（http://www.waterlinemedia.tv/）的有关乐器频率范围及均衡调节技巧的详细图表。



The human voice generally sits smack in the middle of the frequency range. Therefore: you can cut the top and bottom of all the dialogue. A low-pass and high-pass filter is generally what you want to use. This eliminates all of the low and high frequencies that are not necessary for the human voice’s frequency spectrum: the low rumble of a your generator that perhaps was too close to the set, a big truck driving by, or even the movement of your boom operator’s fingers on his pole. To eliminate these cut below 100 Hz and above 10 KHz.

Always EQ the dialogue with the entire mix playing so that you’re not soloing the tracks and working in the dark. Otherwise this can create problems with dialogue clarity in the entire mix. Below are a few tips and tweaks when addressing your dialogue (reverse for opposite effect):
•Male fullness= Boost 120 Hz
•Female fullness= Boost 240 Hz
•General Dialogue= Boost 2.5KHz
•Nasally dialogue= Cut between 2 KHz – 4KHz
•Male sibilance=  Cut between 4KHz – 6 KHz
•Female sibilance= Cut between 6KHz – 8KHz
•Increase vocal presence= Boost 5KHz

Reverb

Early reflections to the human voice can contribute a great deal of presence and realism that EQ simply cannot recreate. Placing the dialogue in the correct acoustical space is a crucial element to obtaining good sound design and a solid mix. This is especially true for ADR work.

Because of the different types of reverbs and effects, the decisions you make creating your acoustical space will vary drastically from each scene, person, and the placement of your actor in relation to the camera angle. For example, your actor may be speaking directly at the camera, then completely turn his/her back to the camera speaking into the distance. Remember, the camera is the audience’s point of view.

So, how would you best demonstrate this in your mix? Usually by automating the volume, reverb, and low-pass filter to the desired effect. EQ is your friend here too. But again, there are no rules. Generally, you want a far-sounding verb and a near-sounding verb on your reverb busses to obtain the correct atmospheric mix.

Summary

We take in a huge variety of noises and sounds in our everyday lives. The sound designer is always taking advantage of these opportunities, consistently thinking outside the box. They are continually scheming and searching for the best way to create engaging soundscapes through experimentation.

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人声一般都主要集中在中频段。所以，你通常可以使用低通/高通滤波器来去掉对白中的那些不必要的 100Hz 以下的低频和 10KHz 以上的高频部分，比如发电机产生的低频振动，飞驰而过的大卡车，更或者是吊杆员手指在杆上的摩擦声。（译者注：切记不可去除过多！可用插件上的 Bypass 按钮来比较处理前后的效果差异。另外，注意降噪处理器对于人声的损害，过度降噪会明显降低语音质量，比如产生高频哨声。）
通常要在所有轨道都播放时，而不是单轨solo的情况下，对对白轨进行均衡操作，不然很容易造成语言清晰度等相关问题。下面是一些有关对白均衡调整的小技巧：
男声丰满，提升120Hz；
女声丰满，提升240Hz；
普通对白，提升2.5KHz；
去除鼻音（Nasally），降低2K-4KHz；
男声去齿音（Sibilance），降低4K-6KHz；
女声去齿音（Sibilance），降低6K-8KHz；
增加临场感（Presence），提升5KHz。
（译者注：仅供参考。部分数值不太符合个人经验。）

混响
在人声中加入早期反射声能很大程度上提高临场感和真实感，而这一点单靠均衡是无法做到的。将对白放置在正确的声学空间中，是声音设计工作中至关重要的部分，特别是对于ADR来说。
根据不同的场景、人物以及演员与摄像机之间的相对关系等因素，你可以使用不同类型的混响效果来创造各种各样的声学空间。比如说，一开始演员正对着摄像机说话，然后他一转身完全背对镜头向远处说话。记住，摄像机就是观众的视角。（译者注：上述情况下，不考虑景别变换的话，前后差异主要体现在“离轴感”上。）
所以你该如何处理这样的画面？通常，调节音量、混响和低通滤波器，别忘了均衡。再说一遍，参数调节没有准则可据。一般来说，你可以在混响总线上调节远距离混响（Far-sounding Verb）和近距离混响（Near-sounding Verb）的比例来获得正确的声学效果。

总结
日常生活中我们每天都要听到包括噪音在内的各种声音。声音设计师们总是抓住任何机会，不断思考。他们一直通过各种试验在设计和寻找最好的方式，来创造出扣人心弦的声音场景。