How to Use a Preamp in a Professional Recording Studio

Preamps are an essential part of professional audio recording. The preamp boosts the minuscule signal created by a microphone to a level you can actually use. Preamps are in many audio consoles and external processing equipment. Knowing how to use a preamp properly will make your life as a recording engineer easier and make your creations sound the best they can.

Difficulty: Moderately Challenging

Instructions

1. Set your input. The first thing you need to determine is whether you're using a mic or line input. A mic input will typically be an XLR cable plugged into a microphone. The mic signal needs a huge amount of boost to get to a workable level, so make sure you are on mic input if you're using a microphone. A line input is a signal coming from something like a keyboard. This signal is already loud so it doesn't need boosting. A preamp is still useful on a line input, though, because it can add color and character to the sound.

2. Adjust your gain. The gain is the main factor for the signal level. Increase the gain until you get a good level on the preamp, and then check the level on the recording source, such as a computer (DAW) or a tape machine. There is probably a meter or LEDs on the preamp that will give you an idea of the output level.

3. Fine-tune if you can. Many preamps have a gain with fixed increments and another knob or controller called fine gain or trim. Use this to dial in the level to precisely where you want it.

4. Use a filter or built-in EQ if needed. Many preamps feature some form of equalization. Sometimes you will find a filter that cuts out low frequencies. You may also have a low cut and high cut, which allows you to cut low frequencies and high frequencies in a specific range. High-end preamps sometimes have a parametric EQ built in.

Tips & Warnings

• Be sure to engage phantom power on the preamp if you are using a microphone that needs power.
• Learn how the preamps sound. You can push some preamps to high levels to get good present sound while other preamps may distort at the same level. Don't be afraid to push your preamp a little, but know your limits.