Bidirectional – Definition & Detailed Explanation – Microphones and Audio Hardware Glossary

What is Bidirectional Microphone?

A bidirectional microphone, also known as a figure-eight microphone, is a type of microphone that picks up sound from two opposite directions. This means that the microphone is sensitive to sound coming from the front and back of the microphone, while rejecting sound from the sides. Bidirectional microphones are commonly used in recording studios, radio broadcasting, and other audio applications where a focused pickup pattern is desired.

How does a Bidirectional Microphone work?

Bidirectional microphones use a specific pickup pattern called a figure-eight pattern. This pattern resembles the shape of the number eight, with equal sensitivity to sound coming from the front and back of the microphone, and minimal sensitivity to sound from the sides. This allows bidirectional microphones to capture sound sources in front of and behind the microphone while rejecting unwanted noise from the sides.

To achieve this pickup pattern, bidirectional microphones typically use two sets of diaphragms that are positioned back-to-back. When sound waves hit the diaphragms, they vibrate and convert the sound into electrical signals. These signals are then amplified and sent to a recording device or sound system.

When to use a Bidirectional Microphone?

Bidirectional microphones are ideal for recording situations where you want to capture sound from two specific directions while minimizing background noise. They are commonly used for recording interviews, duets, or sound sources that are directly in front and behind the microphone. Bidirectional microphones are also useful for recording in noisy environments where you need to isolate the sound source from surrounding noise.

What are the advantages of using a Bidirectional Microphone?

One of the main advantages of using a bidirectional microphone is its focused pickup pattern, which allows you to capture sound from specific directions while rejecting unwanted noise. This can result in cleaner recordings with better clarity and detail. Bidirectional microphones are also versatile and can be used in a variety of recording situations, making them a valuable tool for audio professionals.

Another advantage of bidirectional microphones is their ability to create a natural sound when recording multiple sound sources. By placing the microphone between two sound sources, you can capture a balanced blend of both sources without the need for multiple microphones.

What are the disadvantages of using a Bidirectional Microphone?

One of the main disadvantages of using a bidirectional microphone is its limited pickup pattern. While the figure-eight pattern is ideal for capturing sound from two specific directions, it may not be suitable for recording sound sources that are off-axis or moving around. This can result in missed or distorted sound in recordings.

Another disadvantage of bidirectional microphones is their sensitivity to handling noise and vibrations. Since bidirectional microphones are designed to pick up sound from two directions, they can also pick up unwanted noise from handling or movement of the microphone. This can be a challenge when recording in live settings or situations where the microphone needs to be moved frequently.

How to choose the right Bidirectional Microphone for your needs?

When choosing a bidirectional microphone, there are several factors to consider to ensure you select the right microphone for your specific needs. Here are some tips to help you choose the best bidirectional microphone:

1. Consider the sound source: Think about the type of sound sources you will be recording and where they will be positioned in relation to the microphone. If you need to capture sound from two specific directions, a bidirectional microphone may be the best choice.

2. Check the frequency response: Look for a bidirectional microphone with a flat frequency response to ensure accurate and natural sound reproduction. This will help you capture the full range of frequencies in your recordings.

3. Consider the polar pattern: In addition to the figure-eight pattern, some bidirectional microphones offer switchable polar patterns, such as cardioid or omnidirectional. This can give you more flexibility in different recording situations.

4. Check the build quality: Choose a bidirectional microphone with a durable construction to withstand handling and use in various environments. Look for features such as shock mounts or wind protection to reduce unwanted noise.

5. Consider your budget: Bidirectional microphones come in a range of prices, so consider your budget and choose a microphone that offers the best value for your needs.

By considering these factors and doing some research on different bidirectional microphones, you can find the right microphone to enhance your recordings and achieve professional sound quality.