Volume & Limiters, help...

[Strike911]

okay, so I've been remixing music for a while now and there is one noticible issue that I seem to have: All of my remixes are not as loud as they could be. I turn down everything, throw on a Limiter and... well, that's that. Its all in the name of trying not to get clipping in my song. But now I've realized that I really don't know how to use a Limiter properly, because as I said above, all (or atleast most) of my songs are not as loud as a standard track should be.

So if anyone could shoot me in the direction of some help, or give me a little help I would greatly appreciate it.

Thanks in advance.

[zircon]

Alright, let me briefly break down compressors and limiters for ya.

A compressor works like this. You set a THRESHOLD volume level. When the waveform reaches this threshold volume level, it is reduced in volume. You control how MUCH it is reduced in volume with the RATIO control. 1:1 means that for every dB of sound above the threshold, 1 dB of sound will go through - in other words, no effect. 2:1 means that for every 2 dB of sound above the threshold, only 1 dB will be heard. 5:1 means that for every 5 dB of sound above the threshold, 1 dB is output. And so on and so forth. Thus, if you only want to compress something a little bit, you wouldn't use more than 3 or 4:1 compression. Finally, the compressor has a GAIN knob to increase or decrease the overall volume of the sound AFTER the limiting.

Now, a limiter is simply an extreme form of compression. It has a very, very high ratio (sometimes infinite). In other words, as soon as the sound hits the threshold, you could send 50 dB through it and it will only output the threshold level. You can effectively use a compressor as a limiter if you just set the ratio really high.

Other controls to be aware of -

Attack: This is the time it takes for the compression to take place. This is usually measured in ms. If you have an attack of 15ms, that is pretty quick, but some sound will still be uncompressed. So, if you're compressing a snare heavily, you'll hear the *THWAP* right at the beginning and then within 15s the sound will be compressed.

Release: The time it takes for the compression to stop after the sound has gone below the set THRESHOLD level. Usually between 200-800ms. Any longer and it's going to sound funny.

Knee: This isn't on every compressor, but this basically controls how "hard" the compression activates. When the sound hits the threshold, does it limit it very sharply right off the bat, or does it ease into it? Here's a diagram of what this looks like:

-10dB is the threshold, for that image.

So what are practical uses of compression and limiting?

Let's say you have a recording of a guitar. Throughout the recording, you have quieter parts at -28db, and louder parts at -8db. That is a 20dB dynamic range, which is pretty big. So, you set your compressor to a threshold of -16dB, a ratio of 3:1, and gain of +10dB.

So now, all the parts louder than -16dB are being reduced to around -16dB. Your loudest peak before was -8, and the ratio is 3:1. 8/3 = 2.6dB, so your loudest peak after the compression will be -13.4dB or so. So, the quieter parts are still -28dB, but now the louder parts are -13.4dB instead of -8. That means that the dynamic range is now 14.6dB instead of 20.

But wait, didn't this REDUCE the overall loudness? AHA! That's where the GAIN comes in. We set the gain to +10dB, meaning that the quietest parts are now -18dB, and the loudest ones are -3.4dB. This is pretty loud in the grand scheme of things, but not uncommon for a commercial track. Now, think about it - if you had just pumped up the volume by 10dB before, the peak level would have been +2dB, which is clipping. If you had done that then thrown a limiter on it, you'd still have a big dynamic range. So, compression is very useful.

Of course, in an actual song situation you usually aren't constantly measuring the quietest and loudest parts of your song, so you won't have exact numbers. If you DID, you wouldn't even need a limiter because you'd know exactly how to set your compressor so that nothing would clip. Because this is not the case, it's ALWAYS good to put a limiter set to about -0.2dB or so at the very end of your mastering chain to make sure that some really loud spikes didn't get through the compressor. Some limiters also offer an input drive or saturation function that will boost the volume before limiting it, creating a slightly distorted but often pleasant sound.

Finally, there are multiband compressors/limiters. Why would you use these? Think about the following situation.. you have this kickass bassline and kick part. Man, it rules. You gotta keep the volume jacked up so people can hear it. Then you also have a cool vocal line that's sort of floating above everything else. If you're just using a normal compressor, because you have the bass parts boosted, they're going to trigger the compression of the entire waveform. So when the bass part gets dropped a few dB because it's going over the limit, the vocals might not even be close to that threshold yet. Oops. A multiband compressor gets around this problem by separating the audio into THREE bands (low/mid/high), with individual compressor controls for each. This way, you can compress just the bass but not the vocals, or vice versa. Or anything else, really!

I hope that answered your question.

By the way, this should also explain why compressor plugin presets are not useful. How COULD they be? The nature of compression is such that you have to tailor it to individual tracks. The only time you should be using presets is if you've designed (or come upon) a preset that works really well for a certain type of sound, and you know how to recreate that sound well. This is the situation with me. I have a preset I created for my compressor and limiter that works extremely well for nearly all the original electronic songs I do. However, I can do this because, well, I've written enough original electronic songs that I tend to use the same production techniques in all of them. Thus the approach to mastering is going to be the same.

Edit: Here's an MP3 example of compression in action. The first loop (played for 2 bars) is uncompressed. The next one has a threshold of -15dB, 4:1 ratio, and a little bit of gain. Same peaks as the first one, but you can hear it sounds a bit louder overall. The third one is pretty extreme, with something like a -30dB threshold and 10:1 ratio with lots of gain. Again, not TECHNICALLY louder than the first too but it certainly sounds that way.

http://www.zirconstudios.com/Compression.mp3

[Tyler Heath]

coincidentally, I was just talking about this subject today and had resolved myself to find out more. the tips are awesome, zirc.

I'm not sure if this thread is as good as any to ask this, but does FL have a multiband compressor somewhere that I don't know about? and, if not (of course this would follow) is there a decent free one that you'd like to recommend?

[zircon]

FLStudio 6 comes with a multiband compressor. It's pretty good, though I personally don't use multiband compression because I'd rather just solve volume issues at the production stage (just my opinion though).

If you don't want to upgrade to FLStudio 6 for some reason, pick up the C3 Multiband Compressor, available on KVR.

[Strike911]

Zircon, I cannot thank you enough. I really appreciate your reply. It answered every single question I had. Thank you.

[the_nihilist]

Good mastering compressor settings to start with:

Threshold -6.0

Ratio 2:1

Attack around 200ish ms

And release about the same

Listen for audio that sounds squashed, and adjust to taste. Depending on your preferences, you might want to end up using a compressor that can color things a bit, I find that this can really "glue" a track together.

Then just run that into your limiter. The output ceiling should be around -0.3 to avoid clipping. Again, listen for stuff sounding squashed, and try to avoid it.

[Mark7]

There is nothing wrong with soft sounding tunes. Making it louder will only make the sound worse, never better.

So don't use any limiters/compressors or whatever. Those will only destroy the orignal dynamics. As you may notice the louder the songs are, the crappier they sound.

[Yoozer]

There is nothing wrong with soft sounding tunes. Making it louder will only make the sound worse, never better.

Actually, softer tunes would have a lower SNR .

So don't use any limiters/compressors or whatever. Those will only destroy the orignal dynamics.

A mixer also destroys original dynamics; there's always something going on in the summing chain.

The original goal of a compressor was to make sure you didn't have to ride the faders manually. Since its existance it's also been used as an effect.

Not using compressor/limiters is making the mastering process rather hard, as it's a vital tool to put emphasis or to play down parts -after- they've been mixed down.

As you may notice the louder the songs are, the crappier they sound.

Surely you mean totally overdoing the loudness stuff; nothing wrong with properly mastered albums that simply don't clip.

[Splunkle]

There is nothing wrong with soft sounding tunes. Making it louder will only make the sound worse, never better.

So don't use any limiters/compressors or whatever. Those will only destroy the orignal dynamics. As you may notice the louder the songs are, the crappier they sound.

I find that uncompressed stuff often sounds awesome - if you can crank your speakers up. When I listen to classical, I always crank the knob all the way up, because otherwise I can't hear the quiet bits, and it makes sure the loud bits are loud.

But not everyone has that option. Scenario: You live in an apartment. Walls are thin, and the people in surrounding appartments really don't like noise. Solution: Turn down your speakers.

Scenario 2: You have pez speakers, but awesome headphones. As such, you prefer to use your headphones. The problem is, headphones at loud levels tend to damage your hearing, especially if they are used all the time. Soultion: Turn the headphones down.

The problem now is, if you are listening to an uncompressed song, you can't hear the quiet bits. But if the song is compressed well, that isn't a problem. Sure, you lose some dynamic range, but hey, huge dynamic range isn't very important in a lot of genres.

Conclusion: Compression is cool.

[zircon]

Well, even classical music requires a degree of compression and limiting. You'd be nuts not to have some sort of safeguard against the volume spikes associated with crescendos and loud passages.

[Splunkle]

Heh. I should have thought of that. As Zirc said, killing volume spikes is a good thing. But still, the amount of compression or limiting in a classical song will be almost nothing in comparisson to the latest pop hit.

Also, I would like to add a qualifier to my previous post: Over-compression is sounds like canned badness. Don't overcompress.

So really, the conclusion should read like this:

Compression, in appropriate amounts, is cool.