FL Studio Tutorial - Compression Explained – Part I

FL Studio tutorial explaining compression

It happened more than once to me – when letting others listen to my compositions – that i get the (fair) criticism that my beats and bass are too weak, that the song lacks ‘groove’ or whatever other terminolgy is used. For instance, read the ‘harsh’ judgement below:

…the atmosphere is nice most of the time, but the beat is just a turnoff. it seems very incoherent, overpowered, and out of place. and u use only kick+2 hats? not enough, get some rythmics to it to make a groove not just that pif-pof beat…

To be honest, I love feedback like this. People who try to improve their composing skills really need such input and I always take the effort to thank people for the time and effort of listening and writing a few words.

"My advice is therefore to expose your work and get some of the more skilled people to review it. Do not be upset if the verdict is not as positive as you maybe hoped for. Instead, look for constructive criticism and learn from it."

Anyway, back to compression. I am often advised to use compression to fix the problem with weak beats, lacking groove or to improve the overall sound landscape of the composition. Sounds cool and I know where to find FL Studio’s Fruity Compressor effect,  so that’s easy. See below:

 

 

But while I often just tweak away and listen to the results (without actually understanding the technicalities of how my sounds are transformed), I sensed it would be really beneficial to understand more about compression – now that so many people seem to refer to it as the way to salvage my compositions.

So I started researching a bit and came across the following:

The only thing that'll glue together pulsing drums, gnarly synths, gargantuan bass lines and your favorite spatial ear-candy tricks into a perfectly balanced, ready-for-prime-time mix is compression. Although in the wrong hands it'll suck the life out of your song, compression can be a psychoacoustic elixir that magically smooths out janky sounds, and it will even bring forth texture and harmonic richness from a track that was previously “unfixable” with EQ, reverb or any other effects – article from remixmag.com by Peter Wetherbee, June 1st, 2007.

When I read this I was convinced. Compression really deserves some more attention! This article/tutorial is my attempt to tell you a bit about what I have learned sofar.

Theory

Simply put, a compressor is an automatic volume control.  Sounds that exceed a certain threshold are reduced in volume. Sounds below the threshold are not being reduced. See the diagram below:

 

 

 

The horizontal axis shows the input level and the vertical axis the output level after compression. As you can see only loud sounds exceeding the threshold are reduced, but not the quieter sounds below the threshold. This can make both the quieter and loud sounds to co-exist in better harmony.

Actually, the compressor reduces the gain (level) of the signal by means of a ratio setting. For instance, a ratio setting of 4:1 implies that if the input level is 4 dB above the threshold level, then the output level will be 1 dB above the threshold level (gain reduction of 3 dB). Similarly, a ratio of 8:1 means that if the input level is 8 dB above the threshold level, then the output level is 2 dB above the threshold level (gain reduction of 6 dB). See also the illustration below:

 

 

Now, I mentioned the threshold and the ratio. These are two important parameters to keep in mind. Other important parameters are:

 Attack and Release – determines how quickly the compressor reacts if the input level exceeds the threshold (attack) and falls below the threshold (release). This is best explained via an illustration. See below:

 

The blue line represents the input level and the red line the output level. As you can see, total reduction in output level is only achieved after some time (attack). Similarly, after the input level falls below the threshold, the gain reduction is removed only after some time (release).

Soft/Hard Knees – controls the bend in the curve representing the output level. Again, this is best explained vi an illustration.

 

 

A soft knee slowly increases the compression ratio when the input approaches the threshold, a hard knee implies the compression ratio is applied in full when the input level reaches the threshold value.

Make-up Gain – finally, the make-up gain will increase the output level with a fixed value once the threshold is exceeded.

Read also the below excerpt from an online article - a bit more amusing to read:

Unless you are a trained audio engineer, you probably don't really know what compressors do, and plenty of people who actually understand their function still don't know what to do with them. The paradox is that compression is a subtle signal processor — as opposed to reverb, distortion, a filter sweep, etc. — that is nevertheless more powerful psychoacoustically than just about any other single type of gear you can use on a track. It is likely that a vast majority of the sounds that make up the music you listen to are significantly compressed — often multiple times — to make them throb smoothly in your earholes.

To say that a compressor generally works by reducing an audio signal's level by a certain ratio above a specified threshold would be to reduce its magic to a simple truth that doesn't even begin to tell the story. For one thing, the most interesting elements of that gain reduction occur in its attack and release stages, the slopes of which are rarely consistent. Without getting hung up on largely irrelevant technical details, let's just start by saying that compressors lower the levels of peaks and allow us to bring up the overall level of a signal without clipping.

Imagine a guy listening to a track with his finger on a fader, lowering the fader a little when the signal gets too loud, and bringing it back up when the signal gets quieter. How fast he lowers the fader for hot signals would be the “attack” of his gain-reduction process, and how quickly he returns the fader to unity after the signal gets quieter again would be the “release” time of his compression. The personality of this guy moving the fader, and how smoothly he moves it, determines the musicality of the compressor. If the dude has had too much coffee, he might be a little jerky, perhaps even anticipating what's coming musically; if he's been drinking cold medicine and brandy, or if he's never heard the track before, he might be a little slower to respond overall.

Either scenario could be musically pleasing or might cause an unpleasant “pumping” that feels unrelated to the program material. Conventional wisdom says that to avoid pumping or other undesirable artifacts (in other words, for the compression to be as effective yet transparent as possible), the attack should not be fast enough to swallow the natural rise of the signal, and the release should fall most of the way back before the next signal peak. And both should be as consistent as possible. article from remixmag.com by Peter Wetherbee, June 1st, 2007.

Application

Ok, so now that we have laid the theoretical foundations, let’s see how we can use compression in our compositions. This is really where the problem started for me ;) While the theory makes perfectly sense, figuring out when and where to use compression is not so easy. I found only few resources that go beyond the theorical explanation and only in vague terms describe when compression should be used.

…once you get the hang of it, things'll simply sound better: punchier, solid, smooth and fat. While tasteful compression lets you pull disparate tracks together into a cohesive relationship in a mix, too much of this good thing will make your track sound dull and will take the vibe right out of even the best performance. So at first, be careful and try to err on the side of subtlety because compression is like distortion: Once it's there, it's pretty hard to get rid of, but you can always add more later. article from remixmag.com by Peter Wetherbee, June 1st, 2007 

Get the point?

About a punchier sound, compression can really help making your beat sound punchier. To illustrate, listen to the following two sound snippets. One without compression and one where I used compression to create a more punchy, profound beat.

Sample 1 – No compression

Sample 2 - Compression

Do you hear the difference? It is the same DNC_Kick in both samples and I really didn’t just turn up the volume. Take a look at the Fruity Compressor dialog below:

 

 

These are the settings I used to pump up my DNC_Kick. Take note of the slow attack and fast release. The slow attack will make sure the very first part of the beat sound passes through uncompressed after which compression will kick in and lower the remainder of the sound. This gives the punchy character to the output. The threshold is low, making sure compression really kicks in. The high ratio makes sure that – once the compression will kick in, it will kick in hard (adding this punchy edge to it). I’ve added some gain to increase overall volume of the beat (compensating for the loss of dB level by compression).

I will continue this topic in a next article/tutorial. First of all, this article is long enough as it is and second, I need to do some more research ;)

Hope this FL Studio tutorial was helpful to you. Feel free to leave any comments. Happy composing!

Category: Mixing/Effects