About the Author: Micah Blouin is the Education Market Manager for PreSonus Audio Electronics. An active performer and clinician, he holds degrees from Louisiana State University in Music and Business.
You are a marching band director and need more “oomph” on the front sideline. The middle school needs a public address system for assemblies but also needs to amplify the jazz band concert. Mixing live sound can seem intimidating, but you can do this. Here are some simple tips to help you choose the right mixer for your program’s needs.
What Is a Mixer?
As the name implies, an audio mixer is an electronic device used to collect all the inputs from microphones, electronic musical instruments, and so on; adjust their volumes independently; and sum them, sending the aggregate mixes to various outputs.
Each mixer input is directed to a path called a “channel.” Each channel has input gain (level) control and can be routed within the mixer and to various outputs. You also get a control for each channel’s output level; on most mixers, this control is a slider called a “fader” that you slide up to make the sound louder and down to make it softer.
While a mixer might look complicated, and some offer a lot of features, mixers are mostly a simple combination of controls repeated multiple times (for each channel).
How Many Channels?
First decide how many input devices you need to mix. For a simple public address system, I recommend you have eight channels, as you may need to amplify multiple microphones at once.
For a jazz band or show choir with individual microphones, I recommend a 16- or 24-channel mixer. For a marching band, you can expect to use two microphones (hence, two mixer channels) per vibraphone or marimba; one channel for each additional monophonic input signal; and two channels for each additional stereo signal.
How Do Digital Mixers Differ from Analog?
With analog audio electronics, a microphone converts sound into a continuously varying electrical representation (analog). An analog mixer combines and modifies these electrical signals. A digital mixer is a specialized computer in which the analog signals are described as a series of (usually binary) numbers that can be translated back into sound. So an analog mixer works with electrical signals and a digital mixer crunches numbers.
Digital mixers usually are much more flexible and offer more processing than analog mixers. Analog mixers are generally less expensive, and they’re relatively easy to use because each control serves one clearly marked, dedicated function, so you always know what every control does.
Here Are Some Features of Popular Digital Mixers:
- Extensive onboard processing, such as equalization, compression, and reverb
- The ability to record to a computer or built-in recording device
- The ability to remote control the mixer with a laptop, tablet, or smartphone
What Are Hybrid Mixers?
The hybrid mixer operates mostly like an analog mixer but offers some digital features. For instance, a hybrid mixer may include Bluetooth input, which is useful for sending audio from a tablet, a smartphone, or a Bluetooth-equipped, teacher-worn headset.
Some hybrid mixers have an onboard recording device that can record to an SD card. Hybrid mixers may also be able to record multitrack, so you can record each channel individually and mix it later with software.
Should You Go Digital or Analog?
If you are directing a marching band, you will definitely benefit from the technology in today’s digital mixers. With iPad control, you can mix from the field, the press box, or anywhere else within the range of a router.
If you’re simply looking for a mixer through which you can amplify two vocal mics in your general music class, a digital mixer might be more than you need.
Don’t let mixers intimidate you. Most mixing functions are simpler than they appear, and plenty of resources are available to help you learn to use them.