{"id":6333,"date":"2020-02-10T10:38:41","date_gmt":"2020-02-10T10:38:41","guid":{"rendered":"https:\/\/currentsound.com\/?p=6333"},"modified":"2020-12-02T12:26:13","modified_gmt":"2020-12-02T12:26:13","slug":"how-to-use-a-compressor","status":"publish","type":"post","link":"https:\/\/currentsound.com\/recording-and-sound-engineering-lessons\/how-to-use-a-compressor\/","title":{"rendered":"How to Use a Compressor – Sound Engineering 101"},"content":{"rendered":"
Learning how to use a compressor is easy if you know how it works. Most effects processors are fairly simple to use; plug in an equalizer (for example), twiddle the controls, and listen to the output, and you pretty much know what you’re doing, and all you need is some experience behind you. <\/p>\n\n\n\n
Compressors don’t fall into this category. Plug them in and\nlisten. What’s it doing? Unless someone has told you, then you probably won’t\nknow. <\/p>\n\n\n\n
Play with the controls. What do they do? Don’t know either. <\/p>\n\n\n\n
What do the indicators mean? Difficult to tell. <\/p>\n\n\n\n
It’s all a bit frustrating really… <\/p>\n\n\n\n
Unfortunately, you need to be *told* what a compressor does.\n<\/p>\n\n\n\n
Furthermore – even after you know what it does – someone\nneeds to explain why the things that it does are considered useful. <\/p>\n\n\n\n
You won’t figure it out for yourself. <\/p>\n\n\n\n
Normally – for non-technical people – the explanations of\nwhat a compressor does, are so bewildering that they end up even more confused\nthan they were before: “xDBs in, equals yDBs out, over zDb threshold,\naccording to this graph” etc. etc. <\/p>\n\n\n\n
Fortunately, I have a friend who explains it very well, and\nvery succinctly: “What does a compressor do, Alan?”, “It makes\nthe loud bits quieter. \u201cI see… But surely if it just makes the loud bits\nquieter, can’t you then turn EVERYTHING right up, and make get everything\nreally, REALLY loud?” “Exactly.” So there you go. Simple isn’t\nit?<\/p>\n\n\n\n
A compressor just makes the loud bits quieter, allowing you to crank everything up to maximum volume. But under what situations would this be useful? <\/p>\n\n\n\n
Firstly, there’s the obvious application of making your music\/mp3s sound as loud as possible. This trend is starting to get a bit silly, and is beginning to prevent people from producing albums of good dynamic range. <\/p>\n\n\n\n
Nevertheless, if you master a rock, pop, hip-hop, EDM or\ndance track with no compression at all, then the chances are it will sound\npitifully quiet compared to the rest of the songs in your playlist. It will\nprobably sound like it has been severely under-recorded. Not to mention,\nspecific genres, especially the bass heavy and club genres mentioned, hip-hop,\nR&B, EDM, other sub-genres of dance are often over compressed and limited\nto give that big loud in your face sound.<\/p>\n\n\n\n
Compression lets you get a much higher average level onto your mp3s (or CDs if you\u2019re still making those) without affecting the music too much. <\/p>\n\n\n\n
A very practical application of compression is in live PA setups such as a rock concert. There is a danger that very, very loud sounds will blow up the loudspeakers as well as risking serious hearing damage for those near the stage. <\/p>\n\n\n\n
The solution is to put a compressor in place. This makes the\nloud bits – and in this case only the very loudest of the loud bits – quieter,\nso as to avoid damage to equipment (and people). Such hard compression of only\nthe very top peaks of music, is called “limiting.<\/p>\n\n\n\n
In the digital and plugin world, usually a compressor and a\nlimiter are two different plugins. In terms of hardware there are some\ncompressors that also have a limiting function as well as individual limiters\nand compressors. Limiting is often done over the whole song and is less common\nto be used on individual instruments and sounds. <\/p>\n\n\n\n
Another example of when compression is used is to compensate\nfor the fact that many vocalists have poor microphone technique and control\nover their dynamic range. When they sing quietly, they sing *far* too quietly.\nWhen they sing loudly, they are *way* too loud. A compressor can reduce the\n“dynamic range” of the vocalist to a more manageable level, which is\nwhy a compressor is sometimes called a “Dynamics Processor”. <\/p>\n\n\n\n
In fact, most vocals will benefit from compression in recording. Evening out the volume of the vocals helps the vocals as they say, \u201csit in the mix\u201d which means there not overpowered by or overpowering the other instruments in the song. <\/p>\n\n\n\n
In the days of analogue recording, the engineer would manually move the fader for the vocal track on the desk up and down depending on how loud or quiet the singer was singing each phrase. This would allow the compressor to work less hard and for the reduction effect of the compressor to less obvious resulting in a smoother and more natural vocal. <\/p>\n\n\n\n
This is still a good technique (which we can discuss in another lesson) but these days most home studio guys, especially those recording themselves, rely even more on compression to even out the dynamic range of their voice.<\/p>\n\n\n\n
Bass guitar is another instrument which can be hard to play consistently throughout a song. Any minor errors in the bass guitarists playing can leave “holes” in the song where the bass seems to disappear. <\/p>\n\n\n\n
This works for all instruments in a song.<\/p>\n\n\n\n
A compressor can help keep the performance at a consistent\nlevel. There are obviously many other instruments and sounds that could benefit\nfrom compression at some time. So, as you can see, there are many applications\nfor a compressor. Basically, in any situation where sound volume levels are\ngetting out of control, a compressor can be used to “tame” the\nextremes of volume and keep it within a reasonable range, entirely according to\nyour needs. <\/p>\n\n\n\n
Now that we know what a compressor does, we can start to learn how to use a compressor. <\/p>\n\n\n\n
Since compressors have many different applications, the way that you use a compressor depends very much on what you are trying to achieve with it.<\/p>\n\n\n\n
In this article, we will look at four main applications of a compressor which are all quite different. Most applications are just variations on these four different uses, so they should serve as a good starting point for most of the things you will want to do. The four main applications that we will look at, are: <\/p>\n\n\n\n
1. Hard limiting – to prevent speakers or digital recordings\nfrom overload <\/p>\n\n\n\n
2. Compressing an instrument or vocal <\/p>\n\n\n\n
3. Adding “punch” to bass drums and bass guitars <\/p>\n\n\n\n
4. Compressing a final mix <\/p>\n\n\n\n
In addition, we will look at a specialized fifth example: <\/p>\n\n\n\n
1. Side-chaining<\/p>\n\n\n\n
But before we get into these, let’s look at the theory\nbehind compressors and what the controls actually do. This is a little\ndifficult to understand at first, so don’t worry if you haven’t “got\nit” the first time around. It will make more sense after you’ve\nexperimented a bit with a real compressor in front of you. Note that not all\ncompressors have all of these controls, and some compressors are very\n“minimalist” indeed. If you don’t have all these controls, then look\nat the compressors instruction manual to see what preset values the\n“missing” controls are set to.<\/p>\n\n\n\n
Firstly, in order to compress the volume range of something\ninto a more “workable” volume range, you need to have in your mind an\nidea of what the lowest “normal” volume level is, and what the\n“loudest” volume level is, and have a mental idea of how\n“loud” you are prepared to let the loudest get. <\/p>\n\n\n\n