Vocal Gain Staging

On stage and in the studio, a clean vocal signal is often the determining factor in deciding if things sound great, just ok, or downright bad.

Achieving a clean vocal signal seems straight forward enough, but it turns out it’s easier than you might think to get tripped up. We’ll go over some basic guidelines for getting a reliable, clean vocal signal every time – whether you’re in a noisy bar or a home studio.

What is gain staging?

Let’s keep it simple. A “gain stage” is any point in the signal chain where you have an opportunity to change the level – turn it down or turn it up. “Gain staging” simply means managing these stages in a way which yields a signal that is loud enough, but not so loud that it distorts.

Why it’s so important to keep this process in mind is because it’s easy to lose track and distort somewhere in the chain but not at the end - which creates a noisy signal, even when it’s not distorting the master. This type of noise can also build up, giving you a signal that’s just inexplicably bad all around.

Minimize gain stages

With this in mind, the first tip is this: reduce the number of gain stages as much as possible.

The fewer links in the chain, the fewer places you can add noise. Even when you get it right, each new component in an analog chain has its own noise floor (ambient noise created by the gear). So, it’s prudent to minimize the number of gain stages.

Microphone

The first link in the chain is obviously the mic. First, get the mic as close to the source as possible. This allows the gain to be lower in general, which reduces the extra noise from the stage and the room and decreases the noise floor.

Next, if the mic has a pad, don’t use it unless it’s absolutely necessary. Engaging the pad introduces extra noise into the system and requires you to boost the preamp gain, which adds further noise. If the vocalist is just too loud, then you may need the pad to avoid distortion, but if not, leave it off.

The same is not true for the high pass filter. For most vocalists, there’s little to no sound information below about 100Hz anyway, so it can be quite useful, especially in a live setting, to use the filter and remove rumbling, handling, and low frequency stage noise.

Preamp

All microphones put out a level far too low to use. So, the pre-amplifier is the one gain stage you absolutely have to have, in order to boost the mic’s signal. On a mixer, the preamp stage is the tiny knob usually marked “gain.” Here’s the pro’s way of setting the preamp level:

Set the fader level to unity (meaning it’s neither boosting or cutting). Next have the vocalist sing through the loudest part they’re likely to sing. Bring up the gain knob until the loudest peaks are barely turning the meters red, then back off 12-15dB. This will give you some headroom.

The preamp stage may also have a pad and a high pass filter. The advice is the same here as with the mic, although there’s not much reason to cut the lows again if you’ve done that on the mic.

After that, leave the preamp section alone. Adjust the mix levels using the fader.

EQ

First off, if you don’t have to use the EQ section, don’t. If there’s a bypass button, bypass the EQ (it should also be in bypass when you set your initial preamp gain). If you need to make some corrections, cut offending frequencies instead of boosting desired frequencies whenever humanly possible. When you do boost, be careful you don’t boost so much as to introduce distortion.

Compressors and Effects

Remember that compressors and other outboard gear add another stage and more noise. If you can remove these from the chain, great. If you need a little compression, there’s no crime there, just make sure to listen for added distortion – don’t crank the input up too hard, but make sure the input is giving you a nice strong signal – just under zero if your compressor has a VU meter. This way you’re not adding too much make up gain, which adds noise.

When it comes to effects like reverb, it’s far better to put these on a buss and use an aux send to give them signal. Putting reverbs in line makes overload and distortion really likely, not to mention giving you little control over the dry vocal – and in most live scenarios, uses up an entire effects box which you may need for other instruments as well.

Everybody Else

Finally, in a live situation, your ability to achieve a clean vocal signal without having to drive every stage too hard is directly influenced by the loudness of the band. If you can turn down the guitar amps especially, you’ll find a lot more room to wiggle when it comes to vocals. To really get things tightened up, start reigning in your stage sound from the ground up – with the drums.

 

A full discussion on gain staging can easily get complicated, and there are a lot of ways to make it harder than it needs to be. In the end, gain staging is mainly about maintaining balance throughout the chain, and making decisions that consider the whole picture – not just cranking knobs until you hear something. If you do that, your vocal chains will consistently sound great.

Also in Audio Info & Education