Recording Vocals Part II: Compression and Preamp Settings

Alright, we’re back and ready to keep things moving where we left off. So, recording vocals, pretty annoying right? With all of the little things that can mess up a take – from moving around to just being nervous – can all make for a bad track and some embarrassing moments if it happens to be in front of a lot of prying eyes. But the thing is, most songs use vocals, so might as well get used to it. Seriously though, recording the vocal track for a song can sometimes feel like a daunting task for newer home studio producers who – unless have had previous experience or education – are pretty much shooting in the dark. Even those with a bit of experience might be performing a carnal sin of vocal recording and not even know it – but they sure will notice the affects of them once mixing becomes a huge pain. Anyways, yesterday we brought you guys part one of our Recording Vocals feature where we introduced readers to some of the things they should keep in mind during the entire process as well as broke down some of the essential components that add up to a balanced and clean vocal track. Hit the link to check it out.


 Before we get started...

With recording, we are essentially dealing with two phases – the actual recording phase and post processing phase (pretty much anything you do with the track that isn’t the actual recording part of it, such as EQ, mixing and all of that other important stuff). Now, in order to make sure that your post-processing portion of the job isn’t filled with unfixable problems and huge headaches, you have to make sure that the recording take of the vocals is the best it can possibly be by making sure you follow a few guidelines that we touched on during Part I, such as using the right mic for the singer, making sure the singer uses proper technique while singing as well as a few common mistakes and how to avoid them.

Alright, so now that you know what mic you’ll be using and your singer knows the basic dos and don’ts of proper vocal recording technique, now we can mess around with preamps and compression settings! We need to set up a proper preamp trim level for the track which is essentially how much gain (volume) is going to be given to the mic signal. This setting is calibrated in decibels that range normally from 0 to 60 db. Pretty much all microphones are going to differ a bit on how much gain will be needed but they usually require somewhere between 15-40 db of boost. And don’t forget that if you will be using a condenser mic you will need to have the phantom power engaged. To figure out exactly how much is needed for your particular mic, have the vocalist practice singing the song you’re recording for a bit and make sure the loudest peaks don’t get anywhere near 0dbFS which can be seen by taking a look at your sequencer.

In case you’re wondering, dbFS is short for decibels relative to full scale where 0dbFS is assigned to the maximum possible digital level and anything below that is measured as a negative (such as -6dbFS). To give you an example, let’s say you have a vocal track that peaks at -6 dbFS. It is essential 6 db below the full scale, or peak, of your track. Pretty much, you don’t want to go anywhere near this 0dbFs mark as that will spell an unfixable preamp overload.  Also, make sure you give yourself some cushion, and probably more than just -6dbFS. I’d start at about -17dbFS but you can tweak it a bit until it suits your needs but you can’t actually be certain if it’s the right setting until you look at the waveform of the track.

And just in case you’re using a physical analog mixer, it uses a different scale from dbFs, which is measure in dbVU. You can set that to 0dbvu since it is essentially -17dbFS which will give you ample room to work with.

Make sure the levels on the vocal track don’t go anywhere near the peak but also, if the waveform looks so small to the point where you can barely see it on the screen, it’s probably too low. You’re theoretically aiming for a mid point – get the average sound level as loud as it can without getting anywhere near the peak. Again, don’t forget to leave yourself some cushion in case your singer happens to belt out the best take of their life but a little louder than expected.



Compression is a Terrible Thing to Waste

Ah, the compressor; helping us tone down those loud peaks and bring up those quiet lows but without the meticulousness nature of EQ. The problem though, if you don’t know what you’re doing, compressors can add noise to your track or completely flatten the dynamics of the performance. Now, when it comes to compression, you can either set it in while recording or later on during the post processing phase. I can tell you right now the choice is pretty much up to you as both should give you the same end result as long as you have the settings right but for the sake of knowing, most producers tend to prefer adding compression during the mixing stage since any compression done while live recording cannot be undone.

Also, producers always prefer a raw, unadulterated track to work with rather than one that has already been touched with something that can’t be undone. Also, waiting until the post processing stage means that you can try out several different hardware and software compressors until you’re happy with a certain one, but just be aware that you do have the option and some people actually do prefer recording with compressors live. Such people usually already know what they are going for as far as settings are concerned or simply have a vocalist who like the sound of their voice with compressors and therefore will have more confidence while performing. Regardless of what route you take, you can set up the compressor the same way.


Using Gates

Since compressors pretty much make quiet sounds louder and louder sounds quieter, how to we keep some of those noises in the background from being boosted up too? Gates!  Also known as noise gates and what these guys do is mute sounds that fall below a threshold of your choosing and when set right, they can take care of certain unwanted low sounds such as background movement, turning the pages on a lyric book and even some minor electrical buzz. Gates have two main components – the noise floor threshold and the rate.  The noise floor threshold is what takes care of sound that falls below a certain point which can be set from -50db to -10db. Most tend to have it at around -30db, but be aware that having this threshold too high (which means its cutting parts of the lower volume levels that you actually want, such as the soft part of the vocals) you risk brining in some unnatural effects such words getting cut off too abruptly or sounding choppy. The rate setting can help with this as it is responsible for bringing in a fade out effect before the gate pops into effect, giving gate cut a much more natural sound and can help prevent the tail end of words from ending abruptly. Setting this to about 1 to 1 ½ seconds should be enough.



Finding the Right Compression Settings

Not to be confused with the threshold setting for the noise gate, this threshold is the all important setting on the compressor that tells it when to kick in. Let’s say for example that we have it set on -10 db, it basically means that the compressor will leave the entire signal under -10 db alone. Once it does cross this threshold though, it the signal will be compressed at the ratio you have set. Most people tend to use a 2:1 ratio which is pretty safe and should work as a good starting point. What this 2:1 ratio means is that for every 2 db of actual sound energy, the compressor will only raise it by 1 db. If it were 10:1, it would treat every 10 db as 1 (which I don’t suggest using unless you want a vocal track as flat as a pancake). You can make this concept easier to grasp by simply looking at the first number as db in and the number to the right as db out. Bring in 2 and you get back 1 (on a 2:1 ratio setting). Starting to make sense?

Alright, now the next setting we need to deal with is attack and release. This can be a bit tricky as it definitely depends on what works for the song but not so hard that you can’t easily find the right settings by pure trial and error. You can start off by finding the fastest attack setting and just enough release so that you don’t hear a boost as the words trail off. It will start to sound a bit unnatural if the attack is set too high. Again, the settings on attack and release depend on everything that we mentioned before so experimenting with settings until you find what sounds best is the way to go without having someone actually figuring them out for you. And finally, the output setting, also referred to as the “make-up gain.”  Basically, you want to set this so that your track never goes past that 0dbFS mark we talked about at the beginning of the article but be aware that this can sometimes lower the overall signal of the track so you might need to boost it slightly during the post processing.

Well, that’s it for the recording phase of all this, now you can go out and record! But there is still PLENTY more to do in the post processing phase – plenty more – such as more compression if you want. Also, keep in mind that since you technically can add compression later, you might not want to go crazy on it the first time around. 2:1 is a good ratio since it is enough of a compression to take care of harmful peaks but not so much that it begins to make the track sound unnatural. In the end though, the best way to let this all sink in is to go out there and try it yourself! Remember, since there is no such thing as the perfect settings that work for every single thing ever, this article is merely a guide to point you in the right direction so never be afraid of a little trial and error – it’s still by far the best way to learn!

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