I got 2 emails this week asking about how to make songs loud. One email a week from my mum is a rarity, so I thought this deserved a little thread. I think a lot of this might come from the mastering thread Mr Chainsaw saw started (
http://www.songwriterforum.co.uk/recording/mastering-what-is-it-and-why-should-i-care/)
Many people dont want to pay for mastering or aren't interested in all the other stuff (such as having a master CD, vinyl or whatever printed), but they would like their mixes to be as loud as the songs in itunes.
Note: This could get technical. I'll give a quick how-to summary at the end
Getting loud mixes begins with getting the levels right when recording. This is gain staging. In any analogue hardware you are using (such as your preamp), you need to have it at around 0 VU on the meter on the hardware. This is where it performs best - to explain, I have to get technical for a minute:
In order to calculate the correct ratings for the components you are going to use in an analogue circuit and to give the correct output impedance, you need to know the input levels. Of course, when recording, the input levels will vary as it is the pressure of the sound hitting, e.g. the microphone capsule that determines the size of the voltage created. So, the hardware is designed for a 'nominal' level of usually +4dBu, which corresponds to 0 VU, which is what the units of most hardware meters are - hence 'VU meters'
. So, if your needle is peaking 0VU then you are fine.
Now, here is a stupid confusing part. dBu (and also dBV) which is the 'analogue' recording level is different to what the meters in your DAW show - thats dBFs - the digital recording level. Stupid right? It gets even more stupid: dBFs is not standardized. Loosely, 0 VU corresponds to around -18dBFS. Thats a big difference! Also, the meters in your DAW and on your preamp will respond differently. In a DAW, the time taken for a meter to respond can be less than 1ms. So it responds to the instantaneous peaks, or transients, of the audio. In your hardware, the meters may take up to 300ms to respond (if they are the old style ones with the needle). They then are not measuring the transients, but an average level. Imagine a drum hit. The initial attack might be VERY loud, but it will very quickly die away. Your analogue and digital meters would look quite different when responding to it.
So what does this mean for recording? Well, in order to make sure that when everything is mixed together (cause you know, if you take 1 track and add another track, you are gonna end up with something that is louder than just one of the tracks on their own) you dont get clipping/distortion, you have to make sure you leave ample headroom. Everyone has different ideals when it comes to the level in the DAW, but if you are not peaking over around -10 to -8, everything is good (if you are recording in 24 bit, you can probably increase that, but thats a whole story in itself). This may mean that you have to turn down the input channel on your soundcard or in the DAW.
So, ok, everything is recorded well and now we have to mix.
A general rule I hear bandied round a lot is 'if you set the most powerful instrument e.g. the drum kit or the bass drum' to between -18 and -20dBFs and mix to that, everything will be fine at the end'.
What this translates to is - mix everything so that the master channel is a fair few db below 0. Give some room to allow it to be turned up by the limiter at the end. It's also generally better to turn individual channels down rather than turning them up.
You will probably find at this point, after all the mixing, that your mix is quite quiet. This is normal and good! It's not clipping, distorting, you have set your preamps so that they give maximum signal to noise ratio - in short, everything has been put in place so that you can turn the whole thing up without any nasty artefacts!
Basically, all there is left to do is to put a limiter on the master channel. A limiter is like an ultra compressor. Whereas a compressor will just kind of 'turn down' any audio going over a specific volume, a limiter will prevent it from going over that volume at all. So what you would do, is set the output of the limiter to 0.0 (or perhaps 0.1 to ensure absolutely no clipping) and then turn up the input until it is loud. You will see that as you go up to loud, the actual 'limiting' part will kick - suppressing any peaks that would otherwise exceed 0. If you push it to far, this usually results in it sounding unpleasant. If you haven't set out your levels in a sensible manner beforehand, then you will find you hit this unpleasant point much sooner than you would like.
You can try experimenting with 2 limiters, or putting a compressor before the limiter aswell. Often spreading the work out between a number of processors can maximize the transparency - each processor has to do a little less so you are less likely to push any individual one over its limit. Or, it might just be that you like the colouration of a particular compressor etc..
And there you have, the basics of getting the mix loud!
Summary:
- Loudness begins with correct gain staging during recording and mixing. It's essential to get the best performance out of your hardware and leave enough headroom in the DAW in order to be able to increase the volume later with no artefacts:
1. Have your hardware (often just the preamp) peaking at 0 VU (+4 dbU). This ensures maximum signal to noise ratio while not causing the preamp to distort.
2. Have your input channel in the DAW peaking between -18 to -10 dbFS (note that the values in digital meters are different to those of analogue) . This is leaving plenty of headroom for mixing.
When mixing:
1. Set the most powerful instrument (usually the kick) to be around -18 dbFS and mix everything else relative to this. This should ensure that you still have headroom left when you have mixed in all the other elements. If not, turn down the kick further.
2. Try to turn things down instead of turning them up. It will help prevent you from running into problems the more instruments you add
3. In the end, you should have a minimum of a few db's of headroom on the master channel.
'Turning up the volume':
1. Put a limiter on the master channel, with the output volume set to 0.0. Increase the input volume
2. Find the best balance on the input volume between the loudness you want and the amount of limiting (reduction of the peaks) that is occurring. More limiting = more audible artefacts
3. If you still cant get it loud enough without inducing artefacts, try using more than 1 limiter and spread the work out across them.
A couple of notes:
- If you are after REALLY loud music, it is very hard to do this well with just plugins. This is where expensive hardware gear and/or the expertise of a mastering engineer will help.
- The more limiting you apply, the more you reduce the dynamic range of your music. It can be a taste thing, but generally music with no dynamic range doesnt sound great and can cause listening fatigue.
- This isn't mastering. Loudness is just a part of what a mastering engineer will do (and a pro will do it on much more sophisticated equipment than plugins)
