Tips & Tricks: Gain StagingDecember 15, 2008
How do you get microphones, instruments, and other gear all to play nicely in your recording or PA system? We break down the basics of managing gain to help you get the most out of your system.
Regardless of which microphone you are using, which audio sources you are recording, or what signal level you are sending into your recording software, sometimes it can be tricky to get the levels you want or enough of certain signals.
Getting the levels right.
The basic principle here is to figure out the dynamic range of your source (singer, snare drum, turntable, sampler, etc.), and then maximize that source’s gain level without distorting or clipping. From there, you can mix the levels of different sources using the faders or volume knobs on each channel. This way, you get the lowest-noise performance and the highest level of flexibility in your mixer or recording system. This is called gain staging.
Before we go any further, let’s define some of the terms we’re using:
- Sound source refers to any device that creates sound. The sound sources a recording or sound-reinforcement engineer deals with are human voices, acoustic and electric instruments, and other electronic sound equipment.
- Signal is the electrical equivalent of sound. Sound is generally created when a sound source vibrates air, and a sound signal is that vibration (sound wave) converted into electrical current.
- Gain is the ability of an amplifier to increase the power or amplitude of a signal.
- Dynamics refers to sound pressure level: how loud or quiet a sound is.
- Preamplifier (preamp) refers to an electronic amplifier that prepares an electronic signal for further amplification or processing. Most commonly, a preamplifier is used in music for amplifying a low-level sound source (microphone, turntable, or pickup) up to line level. Many mixers and some low-level sound sources such as turntables and pickups can contain built-in preamps.
- Line level refers to the operating level of a signal that is easily manipulated by other devices such as mixing consoles, effects, and recording systems. In professional audio, this level is referred to as +4 dBu.
- Noise refers to unwanted system sound (usually hiss and hum) created by electrical components’ operation.
Dynamic microphones (for example Shure SM57 and SM58, Electro Voice RE20, Sennheiser MD 421) are designed to be able to capture very loud sound sources without distorting. These mics can be placed at close proximity to a guitar amp or kick drum with the mixer set to unity gain (applying no additional gain). You can shout into these microphones without generating a signal that would clip (overload) the mic preamplifier.
Condenser microphones (for example Shure SM81, Sennheiser e614, Neumann U 87) are designed to capture extremely detailed sound, so they are more delicate than dynamic microphones.
Both dynamic and condenser microphone have low levels of output, so they require you to pre-amplify them so that you can more easily work with them. Similarly, if you are working with an instrument pickup or a turntable, you will likely need to booth their output levels for best use.
Some great tools for accomplishing this level boost are the Alesis iO series. The iO|14 and iO|26 each have lower noise than many of the legendary mixing consoles and provide up to 50db of gain. This means that these interfaces can apply more clean gain to a signal than many other devices.
Here are some tips for approaching gain in different situations.
Accurately capture the performance with a good signal level, but without clipping (reaching 0dB).
When recording/overdubbing over pre-recorded material, provide the performer with a headphone mix of the pre-recorded material that is loud enough to allow them to perform their take well.
Apply volume adjustments, effects, EQ, compression, and limiting to shape the sound of individual tracks so that they fit well with the other tracks.
Balance the tracks in relation to one another to get the best possible complete picture.
Apply adjustments to the final mix (stereo or surround sound) including EQ, compression, and limiting to maximize the recording’s overall volume and ability to play well on a variety of sound systems.
If a complete album is being mastered, each song is also balanced for volume and overall tone in relation to the other songs.
We hope this is a good introduction to gain staging and management. It can be a tricky concept to master and the best way to improve your understanding and skills is practice. So get out there and start tracking, mixing and, mastering!