Compression for Dummies

Tutorials to help you get the best out of your mixing progies. Please feel free to ask any mixing/editing/production problem questions here.
User avatar
Moderator
Posts: 770
Joined: Tue Aug 19, 2014 11:53 pm
Location: california bay area, usa

Compression for Dummies

Post Wed Apr 01, 2015 4:24 am

Hi, I am a dummy.

Help me understand what exactly compression is, does, how to use it, and anything else helpful about the topic. But remember, I am a dummy, and need to be taught like I am in the 2nd grade.

Thanks!
I am here, and so are you. We can be together at other places, too
Soundcloud
YouTube
Sowndhaus
Facebook

User avatar
Moderator
Posts: 4379
Joined: Fri Mar 19, 2010 7:21 am
Location: around here somewhere...I think..

Re: Compression for Dummies

Post Wed Apr 01, 2015 10:33 am

Compressors... Yeah they're easy to explain - not!
OK so in their simplest terms compressors reduced the dynamic range of a track. Either by making the loudest parts quieter or by making the quieter parts louder (downward or upward compression respectively) and how this basically works is by setting a threshold (level of loudness) and telling your compressor that anything above that threshold needs to have its loudness reduced (downward compression) or by telling it that everything below that threshold needs to have its loudness increased (upward compression) .
In either technique you are reducing (compressing) the dynamic range.

Ok that's the basics, from here on in it gets more complicated so I've had a quick hunt for some easy to understand vids, I'll post more as I find them.
phpBB [media]

phpBB [media]

User avatar
Moderator
Posts: 770
Joined: Tue Aug 19, 2014 11:53 pm
Location: california bay area, usa

Re: Compression for Dummies

Post Wed Apr 01, 2015 11:13 am

Ah, thanks! The first video answered a lot of the questions I had about the particulars of the knobs.

One thing that's still confusing, though, is the 'Makeup' button in Ableton. The video explains what this is for, but it's unclear in Ableton if selecting/deselecting this button is turning it off or on, or just selecting/deselecting it to alter it.

And am I right that the 'knee' option in the 2nd video is called 'dry/wet' in Ableton?
I am here, and so are you. We can be together at other places, too
Soundcloud
YouTube
Sowndhaus
Facebook

User avatar
Moderator
Posts: 4379
Joined: Fri Mar 19, 2010 7:21 am
Location: around here somewhere...I think..

Re: Compression for Dummies

Post Wed Apr 01, 2015 11:57 am

Firstly, I'll need to know what version of Live you're using because off the top of my head the makeup gain is a slider not a button... Unless you're talking about the glue compressor which has a rotary knob, it's also the only one with wet/dry which by the way isn't the same as soft/hard, what wet/dry is is the amount of parallel compression; 50% being true parallel.

User avatar
Moderator
Posts: 770
Joined: Tue Aug 19, 2014 11:53 pm
Location: california bay area, usa

Re: Compression for Dummies

Post Wed Apr 01, 2015 3:53 pm

I'm using Live 9, but should have paid attention to the descriptions Live gives when you hover over an option, which explains what things do (but, remember, I am a dummy).

This is the layout:

Image

According to Live, that yellow Makeup key is an on/off switch for auto Makeup. And the dry/wet is not related to the Knee setting, which happens to be conveniently shown just to the left of that dry/wet knob..

One thing I don't understand now, though, is the 'Out' slider, which is for adding Gain tot he compression. I must be missing the point there with my ignorance, but it seems to me like that is simply negating the compression you just did to the Gain by pushing it back up again. If it is to boost the Gain on everything under the threshold, though, is that then the makeup Gain slider?

It's like, I think I get the idea here, but then when I get with all of the different sliders and dials together, I get lost.
I am here, and so are you. We can be together at other places, too
Soundcloud
YouTube
Sowndhaus
Facebook

User avatar
Moderator
Posts: 4379
Joined: Fri Mar 19, 2010 7:21 am
Location: around here somewhere...I think..

Re: Compression for Dummies

Post Wed Apr 01, 2015 4:27 pm

The concept of gain is pretty straight forward, when you bring the threshold down it reduces the overall volume... The gain puts the volume back.
Maybe you're not understanding the role of a compressor in a mix... It's not to reduce volume, it's to make the quieter things audible. You do this by reducing the dynamic range and then adding gain.

User avatar
Moderator
Posts: 770
Joined: Tue Aug 19, 2014 11:53 pm
Location: california bay area, usa

Re: Compression for Dummies

Post Wed Apr 01, 2015 5:01 pm

lloyd wrote:The concept of gain is pretty straight forward, when you bring the threshold down it reduces the overall volume... The gain puts the volume back.
Maybe you're not understanding the role of a compressor in a mix... It's not to reduce volume, it's to make the quieter things audible. You do this by reducing the dynamic range and then adding gain.


What I don't understand then is the threshold. I thought that it simply reduces the volume of anything that jumps over that threshold line, leaving any audio below that db threshold line anaffected. Why would it reduce the overall volume (as in, all of the audio that plays below the threshold line also becomes quieter)?

I understand that the purpose is to bring the dynamic range in, making the quiet and loud parts more balanced and even, as the reason I want to learn it is that my tracks are coming out quiet overall when I reduce volume to avoid clipping.

Maybe the idea is, you set the threshold at the desired db you don't want to exceed, and then raise the gain of the overall track, now knowing that it won't raise above that threshold line? But when I raise the gain after setting the the threshold limit, it seems as though it ignores the threshold I have selected, and clips. Maybe I'm just imagining this, or am not reading the multiple fader readouts correctly?
I am here, and so are you. We can be together at other places, too
Soundcloud
YouTube
Sowndhaus
Facebook

User avatar
Moderator
Posts: 4379
Joined: Fri Mar 19, 2010 7:21 am
Location: around here somewhere...I think..

Re: Compression for Dummies

Post Thu Apr 02, 2015 6:26 am

Hi it's obviously hard to comment without being in the same room but puting all your comments together I'll try to see if I understand.
You are correct the stuff below the threshold won't be effected but it sounds to me that you are starting with your track too loud in the first place. If the quieter sections are already audible and you're trying to reduce the loud sections then you're going about things backward.
Secondly just as an observation you appear to be using peak as your setting... Great for drums useless for everything else... Stick to rms
Have a quick look on YouTube I'm sure you'll find a tutorial that explains the settings. If not ill try my best to explain later.

User avatar
1 star User
Posts: 133
Joined: Wed Jun 30, 2010 10:03 am

Re: Compression for Dummies

Post Thu Apr 02, 2015 7:38 am

Threshold is the level where the compressor starts working. Any audio above that level will be compressed.
Ratio is the amount of compression; 1:1 being uncompressed, 2:1, 4:1 etc becoming more compressed.
Attack is how soon after going above the threshold do you want it to start compressing.
Release is how soon after audio drops back below the threshold it stops compressing.
Makeup/gain/output is just an overall volume control.
Knee is how aggresive you want the compressor to kick in at the threshold.. A hard knee starts compressing exactly at the threshold, a soft knee starts compressing slightly before the threshold but at a reduced ratio so the higher it goes past the threshold the higher the ratio will be until it reaches your setting.

How you set the compressor depends on what you're using it for. You seem to want a "mix gel" and general boost to a finished track so here's how I would do it...
Reduce all tracks so they're not clipping. I would have them peaking about -6db so there's plenty headroom to play with.
Add compressor on the master channel.
Set a low ratio (1.2:1, 1.5:1)
Leave attack and release at default or auto.
Reduce the threshold slowly until you hear it working.
Increase the gain/output to bring the overall volume level back up again.

User avatar
Moderator
Posts: 770
Joined: Tue Aug 19, 2014 11:53 pm
Location: california bay area, usa

Re: Compression for Dummies

Post Thu Apr 02, 2015 2:31 pm

Okay, I get what you guys are saying. Now putting the info to action will involve more learning, I'm sure.
I am here, and so are you. We can be together at other places, too
Soundcloud
YouTube
Sowndhaus
Facebook

Next

Return to Mixing Tuts and Stix Support Center

Who is online

Users browsing this forum: No registered users and 2 guests