Sound mixing and audio equipment technology have come a long way since Édouard-Léon Scott de Martinville made the first sound recording on his phonautograph. These days, every professional setup has a mixing board and preamp, whether you’re in the studio or performing live. But do you really need both?
You do need both a preamp and a mixer. However, most mixers have a built-in preamp already. Using an additional stand-alone preamp is optional if you need to alter the color of the sound, boost the signal more than your mix desk allows, and use more gain than the built-in preamp can give.
The more complex your audio needs are, the more likely you are to need a stand-alone preamp. You’ll also need to check your components to make sure your mixer’s built-in preamp can accomplish what you need. This quick guide will help you get started.
What Is a Preamp?
In the simplest terms, preamps boost low-level frequencies without adding too much noise or distortion. When you’re working with audio, you need to bring every signal you’re using up to the same base level, also known as line level. Preamps let you do that, no matter what your input device is.
Every microphone needs some kind of preamp. In order to use the signal from a mic for literally anything else, the sound wave needs to be boosted a little. Preamp stands for “pre-amplification.” Think of a preamp as preparing a sound wave before you amplify it, whether you’re putting that sound through a speaker or into a recording device.
Most sound engineering devices have some kind of preamp built-in, including everyday objects like headphones or computers. Preamps give you a cleaner, less distorted sound than you would get if you went straight to amplification.
Some preamps can alter the tone of the sound, depending on how they’re made. Older preamps that use tubes add warmth to the audio, whereas preamps with circuits have brighter tones. This difference is important to consider when choosing your equipment.
If you’re looking for a great single-channel microphone preamplifier to get started, we recommend the Grace Design m101 (link to Amazon).
What Is a Mixer?
Mixing consoles are a more complicated piece of audio tech. A mixer lets you manipulate multiple sounds—i.e., mix them—before sending them through a single output. Mixers are useful for live performances and recordings to balance different elements, where each gets its own channel on the mixer.
While mixers aren’t necessary when you only have one channel, they are still useful. You can use a mixer to adjust gain levels and reverberation so that your sound is the best quality for the space you’re in.
There are numerous kinds of mixing consoles, depending on what your goals are. Recording studios have enormous mixing consoles because they have to record many channels simultaneously (one for each instrument and microphone) while also sending feedback to headphones in the studio so that performers can hear themselves.
On the other hand, a simple acoustic concert or an event where speakers use only one microphone would need a much simpler mixer with far fewer channels.
A great all-round USB mixer with a built-in audio interface is the Behringer QX1204USB. It has multiple channels, XENYX Mic Preamps, and professional quality controls at an affordable price point.
How complex your mixing console is determines what you can do with the sound signals you get before you send them back out, either to a recording device or a speaker. Some mixers let you add effects or distortions. All mixers, however, function basically the same way, letting you turn channels up or down to adjust the gain and input from each channel.
Can You Use a Preamp Without a Mixer?
In the most basic setups, you can use a preamp without a mixer but not the other way around. You can plug your input devices (microphones, pickups, etc.) directly into a preamp and then an audio interface without mixing. When you’re only using one audio input, and therefore only one channel, a mixer might not be necessary at all.
When Do You Need Both a Preamp and a Mixer?
On the other hand, if you’re using a mixer, you’ll need a preamp. For sound to be usable in a mixer, you have to bring it up to line level, which requires a preamp.
However, all mixers have preamps built-in now, so you may not need a separate one depending on your goals and how good the preamp in your mixer is.
Certain microphones, like ribbon mics, need more decibels of gain than a standard built-in preamp can give you. Any input device that’s lower or quieter could benefit from a separate preamp.
In short, having an external preamp will improve your sound quality, but not having one isn’t necessarily a problem.
The other scenario where a preamp is absolutely necessary is if you’re trying to add a very specific audio characteristic to your sounds. The preamp that’s part of your mixing console is likely designed to be as close to the original sound as possible. It’s not possible to avoid all distortion and added noise, but an external preamp lets you choose what kind of distortion or color you want. The standard preamp in the mixer will minimize any distortion and color.
Can You Use a Mixer as a Preamp?
In many scenarios, your mixer will work as a preamp. The built-in preamps are sufficient for amateur use and some professional use. However, if you want anything other than a clean, bright sound, you’ll need to use an external preamp.
Modern mixers use circuitry preamps and won’t give you the same tones as older transducer tubes or transistor devices. In order to recreate or mimic those audio colors, you’ll need to use an external preamp before you feed your audio signals into your mixer.
Just as a more sophisticated mixer gives you more options in how you master a piece of audio, adding an external preamp gives you the ability to make more sophisticated sound choices. Having an external preamp will give you more features before the signal even reaches the mixer.
The type of sound engineering you’re doing will inform your preamp and mixer needs. The setup for an audiobook or a podcast will look different from a live stadium concert or a concert hall. You’ll also need to consider whether you need playback, recording, amplification, or a combination of some or all of those components.
When you’re just starting out, using a good mixer will give you the tools to learn the trade. As you learn more, you will better know which situations call for which tools. Furthermore, you’ll learn what your own preferences are to get the best control of your sound.
The more complex your audio needs are, the more likely it is that you’ll need both a preamp and a mixer. Even though mixers almost always have built-in preamps now, using an external preamp will give you more sound options for the final output.
Whether you’re making a recording or performing live, having a mixer and a preamp will give you higher sound quality. If you’re just starting out with sound engineering or don’t need anything fancy, a mixing console alone should be fine. But if you want a polished, professional output, you’ll want to invest in a preamp.