Hi All -

A very subjective question here about engineering, thanks for bearing with me.

I've read about (and I'm mainly talking vocals here) how compression will make vocals "sit in a mix" better, how they will be "glued" to the mix, etc. As background, I know at this point how to compress in the crudest terms - get X dB of gain reduction by adjusting threshold and ratio, then applying makeup gain, etc.

What I never really understood is what this is doing besides a) smoothing out the dynamics, and b) maybe adding some "color" (I do know what that term means!) just by going through the circuitry of the compressor.

What more can the process do? What do all the engineers mean when they write about compression using those other vague terms (at least they're vague to me at this time!)? To help me understand, for example ... if I were to manually automate my vocal volume curve, would it "sit in the mix" just as well as if I ran it through a compressor? If not, what is the difference?

Thanks for any help!

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Alexis -Cubase 6.5.0/SX3.1.1.944, XP SP2, 4GB RAM (1GB not accessible, but used just to balance the computer so it doesn't tip over); Delta 66 in Omni i/O Studio; Motif8; UAD-1

I tend to think of "glue" compression as only being applicable to busses or whole mixes (ie. compression acting over multiple sources, rather than just one).

For example... Even if individual elements in a mix are compressed (kick, snare, vocal, guitar etc), their dynamics will still be independent of each other, so a loud kick won't have any effect on the volume of a guitar part (except maybe psychoacoustically, but let's ignore that for a moment).

If you slap a compressor over the mix, however, that ceases to be the case: a loud kick is very likely to trigger compression, ducking the level of the whole mix (so your guitar part will, effectively, become quieter, along with everything else). This makes the dynamics of all the individual elements quite interdependent, and as such they sound like they're part of one big sound, rather than a collection of individual sounds — hence, "glue".

Cheers!

Chris

Side-chaining is often the way forward for that 'glue' thing - you can use the vocal to push the levels down on things like strings or pads (so they come up when the vocal isn't there), the drums to 'sit' on the reverb so that it comes forward in breaks but goes back as soon as the drums kick back in... all kinds of things which 'semi-automate' the mix levels and generate dynamic interrelationships between different elements. One fav of mine is to have delays routed back to themselves but with the send pushed down by a sidechain from something else so that it's on the edge of feedback but not quite there - as soon as whatever's on the sidechain (drums, say) disappears from the mix the delays go banging off into feedback, then get sat on again when the drums come back in. Great for that really nice 'almost falling apart but not quite and really banging along' vibe ...

Used on extreme settings you can really get things to pump in all kinds of ways- which can be overused (the first track on Bonobo's latest album is a classic way to go over the top- way, way too much for my taste but I guess he likes it) but if you're a bit more subtle about it it can far more effective than messing about with track automation - though you can of course use the automation in tandem, since automating at the track level will also affect what happens to the compression. One to fool about with until you get the hang of what's going on.

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http://anotherfineday.bandcamp.com/ http://anotherfineday.co.uk http://apollomusic.co.uk

Quote alexis:

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I've read about (and I'm mainly talking vocals here) how compression will make vocals "sit in a mix" better...

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True. The dynamics of a vocal can mean that some phrases/words/syllables will disappear under the mix, while others will be overly prominent. An audience wants to hear every word of the vocal, but they don’t want the music to be overpowered. Compression helps you find the balance where the vocalist seems to effortless carry the song's message through the music (though it’s not the only tool for achieving this).

Quote alexis:

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...how they will be "glued" to the mix...

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Not a phrase I’ve heard used in this context, but I’ll go with it. Vocals that are overly-dynamic for the song can sound like someone singing over a karaoke backing track. This can be distracting and make the whole recording sound amateurish. Again the object (at least the objective that I often follow) is to make the vocalist sound as if they're in control of what you hear - not struggling to be heard, or shouting at you.

Referring to the ‘gluing’ properties of compression is more often aimed at mix buss compression, where an appropriately set compressor can make a mix sound ‘right’. This is often associated with finding attack and release times that let the music as a whole ‘breath’ along with the song’s rhythm.

Quote alexis:

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What I never really understood is what this is doing besides a) smoothing out the dynamics, and b) maybe adding some "color" (I do know what that term means!) just by going through the circuitry of the compressor.

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I think ‘colour’ seems to mean a variety of things depending on who’s speaking! Certain compressors have certain characteristics that can affect not only the dynamics, but also the overall tonal character of material that passes through them - sometimes this is a good thing, and sometimes it isn't. I'd say 'colour' is a description of these tonal characteristics - whether this is good or bad is in the ear of the beholder.

Quote alexis:

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What more can the process do? What do all the engineers mean when they write about compression using those other vague terms (at least they're vague to me at this time!)? To help me understand, for example ... if I were to manually automate my vocal volume curve, would it "sit in the mix" just as well as if I ran it through a compressor? If not, what is the difference?

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If you were to use automation to carefully go through your vocal take and ride the volume with the speed of a bumblebee’s wings then you’d be performing the job of a compressor! In fact I’ve seen a few beginners’ guides to compression that start off by asking you to imagine a compressor as someone riding the fader for you.

You’ll hear all kinds of talk about compression. Sometimes it’s vague because someone is oozing ill-informed snake-oil, sometimes they’re very knowledgeable and just assume their audience is too. Often you’ll find it vague because there is no one tool for all occasions and there is no one way to use all of those tools.

Using compression is not a universal solution – and is not always a good thing to do. Sometimes you need the dynamics in a performance for it to do its job.

In the context of a vocal a carefully set compressor can help a vocal ‘sit’ as I’ve mentioned above, but it can also help to improve diction, often by using a longer attack time. At other times it can be used to simply tame over-enthusiastic consonants by lowering the attack time. A de-esser is actually a form of compression set to hold back the level of sibilant vocal sounds.

Quite often I’ll use multiple dynamics processors on a vocal to help with different aspects of a vocal, maybe a multi-band compressor to keep the vocal bright and clear, a de-esser to shave off the sibilant peaks, a compressor to help the song’s story make it through the mix’s melee of instrumentation and maybe parallel compression to further help the vocal make it through the mix. And then I'll automate as well if I need to. It’s all about listening, deciding what you want to do and picking a tool from the toolbox.

Of course using compressors with other sounds each have their own requirements and a story all their own. Compression can add or subtract transients, hold back or lift ambience... it’s a big subject!

There’s a lot of good information in the SOS archives and some good stuff around on the net. Unfortunately there’s also a lot mis-information too - unfortunately it can be tough to tell the difference when you’re learning (one clue – if it’s a video by ‘Expert Village’ then run screaming in the opposite direction!).

HTH!

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An Eagle for an Emperor, A Kestrel for a Knave.

Part of the thing to realise about hardware compressors (and their software modelled equivalents), is that they do more than compress. (IIRC for the following info...) An LA2A is a simple opto-compressor, but has a "smooth and warm" valve amplifier for makeup gain. An 1176 has FETs that distort when driven in a particular way, and a posh lundahl audio output transformer. A Neve 33609 has a diode bridge and more carnhill transformers than you can shake a stick at. Carnhill transformers sound lovely. A Fairchild is a vari-mu valve compressor that uses valve circuitry to compress and adds subtle harmonic "warmth" as it does it.

Most of these things have little to do with compression but are well know for imparting nice audio qualities to signals run through them.

So quite aside from the leveling features (which do help things sit in a mix, add glue etc) these things just sound good.

A good comp applied to all of the mix with a low threshold brings up room tone and detail.
A multiband comp gives more freedoms and possible expansion.
A limit facility is essential.

Lets face it a good C is essential if we record HiRez and want punters to be able to hear it at home.
So we record all those lovely transients in full detail, with bags of headroom and then mangle them.
Hey Ho.

My old Nagra did that free of charge and with plenty of Xformers as a bonus.

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I am the Walrus.

To the O/P

As a compression 'victim' I'd like to ask you to use it as sparingly as possible.

I hear more and more music being totally destroyed by what sounds like someone frenetically wanging a fader up and down like their life depended on it

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It wasn't me!
(Well, actually, it probably was)

Compression - easiest, simpliest powerful weapon to make your mixes to sound like commercial radio expensive songs (as soon as you'll get the point). But one problem, always misunderstood. I had no idea what compressors do when first started learning about them and I hated when working with them. But now, It's pretty fun.

Compressor is a magical and mysterious unit. The main purpose was and still is used to control the dynamic range. What do I mean by that, the difference between quiet sections and loud sections - that is the dynamic range. Put in other words, or visualize, to EVEN the audio.

Reducing the louder sections + increasing the level of quiet sections = compression.

For an instance, play a game with a fader. When the music is too loud, reduce it, when it is too quiet increase the level. Congratulations you just became a manual compressor.

To become more familiar with compressors you need to understand and recognize the difference in volume. Understand the decibels and I'm sure you'll get the point more quickly.

But, compressors are not just used to control the dynamic range (they were designed about it, and actually we're still using about that nowdays), or to make all words audible. They can do a little more. They can create a magic. Sometimes you'll have a vocal which is, in control (dynamic range will be ok), but put it through a compressor and it'll add a sparkle, crystal warm sound. Such as vacuum mu-variable compressor. Each compressors are different, and have a different process of achieving the compression, such as diode-bridge, opto, vacuum tube mu-variable etc. different methods. As I said, each compressor is unique, and has its own magic, you judge if that magic is suitable for you by listening as many compressors as you can.

I'm sorry. I've read this thread through and it still sounds "magical and mysterious" to me.

CC

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Put the fun back into dysfunctional.
Mr Punch's Studio

All these replies have been most illuminating - thank you all so much! A lot of good stuff to think about ...

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Alexis -Cubase 6.5.0/SX3.1.1.944, XP SP2, 4GB RAM (1GB not accessible, but used just to balance the computer so it doesn't tip over); Delta 66 in Omni i/O Studio; Motif8; UAD-1

In years of assisting some serious engineers, I never heard any of them use the word glue - seems to be a word mainly written in magazines. I thought it was to use a low ratio and threshold so you're reducing the dynamic range of the whole signal by a little bit as opposed to dealing with the peaks harshly with a high ratio. Mainly used on vocals and compressors over the mix before any limiting.

To 'colour' I gather is to eq a signal in a subtle way using broad bell or shelf filters as opposed to notching or precision eqing. Again, I had never heard of that either until fairly recently.

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http://www.musicproductioncourses.net

The problem with a static mix is that some instruments will jump out at some times and get buried at others, due to the dynamics and frequencies of the different sources or recordings. The mix will not seem like everything "works", "mixes", "blends" or "coheres".

Reducing the dynamic range a little can help this mix of instruments to appear to belong together a little more in a musical sense -things won't obscure or mask each other quite so much (EQ and panning, and good recordings of good instruments help here too)

This apparent improved mixing or belonging of sources can be said to "gel" or "glue". The better your musical arrangements, your instruments, your players, your mic technique and your recordings, the less you will need compression to do this.

It's always difficult to describe audio concepts in words, sometimes the language seems strange.

>

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planet nine
lincoln, uk.

Ah, thanks. I can understand that.

Cheers,

CC

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Put the fun back into dysfunctional.
Mr Punch's Studio

Quote Dave Garnish:

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To 'colour' I gather is to eq a signal in a subtle way using broad bell or shelf filters as opposed to notching or precision eqing. Again, I had never heard of that either until fairly recently.

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It's used fairly broadly to mean passing a source through some process that is not necessarily "clean" or hi-fi; to add "character".

Old tube equipment, and old compressors (tube and transistor) are said to colour the sound that passes through them, partially through frequency changes and constraints of their signal path, but also from harmonic distortion introduced by their circuit types, any thermionic (tube) active circuitry and the isolating transformers used on their inputs and outputs.

They might be compressing, but they're doing other things to the signal too, and some people really like these distortions. Sometimes, some engineers pass signals through them for this "character" or "colour" without using the compression functionality of the equipment, just their colour. Some modern ADC/DACs posess this too.

And Dave, these engineers wouldn't use the word glue, because their mixes probably wouldn't need "gluing"

>

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planet nine
lincoln, uk.