Showing posts with label Microphone. Show all posts
Showing posts with label Microphone. Show all posts

Sunday, 18 September 2022

Parabolic Microphone

Parabolic Microphone

A parabolic microphone is mounted inside a sound-reflecting dish. The reflecting dish of a parabolic microphone focuses on the sound waves passing straight into the reflector. Besides, the reflecting dish of a parabolic microphone has a cross-section on the device. In addition, sounds entering from other angles impinge directly on the device. But these are not focused on by the reflector.

Thus, the device has become highly directional. In addition, it becomes more sensitive to sound sources. It makes the device worthwhile to record localized sources of relatively faint sounds like bird calls, conversations, etc.

What is a parabolic microphone?

A parabolic microphone is an electronic element that converts sound pressure into an electric signal. As we mount the device inside a parabolic dish, it is called a "parabolic microphone."

The dish collects the incoming pressure due to its shape. After that, it will focus the pressure on a single point. Then, the device converts this into an electrical signal. In this case, you can find the sound amplified. The reason is that the sound energy from a large area is focused on a single point. Besides, you can amplify the electrical signal from the mic.

What do you know about its history?

In 1888, Heinrich Hertz, a German physicist, made the world's first parabolic reflector antenna. However, people have known its principle since classical antiquity. You can find detailed knowledge in the famed mathematician Dicoles's book On Burning Mirrors. This physicist proved that parabolas focus a parallel beam in a specific direction.

People have been following the same principle through the ages. Even, Acoustic Mirrors used this principle to identify enemy aircraft before the advent of radar.

Why Use a Parabolic Mic?

It can give a mechanical amplification of about six times for the collector dish. As this dish comes in a unique shape, it can collect the incoming pressures of sound waves. After that, it helps to focus these onto a point: a mic. Generally, the mic has an omnidirectional pattern. Besides, sometimes, it has a cardioid pickup pattern placed within the dish. But remember that it relies on the dish size.

The amplification level is consistent over the whole area of the parabolic dish. In addition, this device can pick up ambient noise from the mic's rear side. But you can hear non-amplified sounds from the dish's amplification. It comes from the back side of the mic. In this regard, you should know that the peripheral sounds are not amplified. Therefore, the dish blocks it. As a result, the device gets a direction.

In addition, this mic can offer only directional sound. Besides, it can pick up the sound at great distances, like hundreds of feet. Moreover, these can amplify low sound pressure levels from a distance and reduce ambient sounds simultaneously.

How to use the parabolic microphone?

The device uses a reflector for the unique geometrical properties of the parabola. Hence, you must know about a parabola, an open curve appearing as a V with a rounded point. It represents the two arms of the curve which go on forever ( according to the mathematical definition). In this case, the axis is a straight line that passes it through when a vertical line is drawn through the center of a V.

In the specific position, you can see the mic placed. Sound waves which enter the parabolic microphone dish are parallel to the axis. Thus, these are focused on the mic and are amplified.


There are different applications of the device. We have given here a few of them.

  • You can use it for nature sound recording, like recording bird calls, and field audio for sports broadcasting. 
  • Besides, it is suitable for eavesdropping on espionage and law enforcement conversations. 
  • People used these devices in World War II and other wars worldwide. Japanese mainly use it.
  • It is perfect for sporting events, surveillance, sound library collections, search & rescue, wedding shoots, and videography.

How does parabolic microphone work?

The collector comes in a unique design shape. Therefore, if something comes towards the dish parallel to the dish's center line, it will make it focus on a point. Understanding a parabola's mathematical formula helps you learn this specific shape concept. It is the reason behind the naming of the dish.

In this case, the energy you want to focus on within the dish does not matter. The reason is that the dish can focus light, sound energy, or electromagnetic energy. Besides, the dish works same as a satellite dish that collects electromagnetic signals from satellites in space.

How important is the shape of the dish?

Remember that the dish shape is cruial. You won't get the best performance if manufacturers don't make the dish in the exact shape. In this case, try to match the perfect geometric shape of the parabola.

A few brands can withstand only a few thousandths of an inch. However, it is possible to pick up the sound from a dish. It doesn't matter if the dish is made poorly. Hence, you can find the sound garbled and distorted.

Moreover, the sound energy ends up scattered when the shape is not perfect. As a result, it cannot focus on a point reducing the amplification.


These dishes are available in several parks, museums, and science centers. Besides, you find any dish enabling a whisper to be heard across a long distance while standing at the focus point. We know them as "Whisper Dishes." These are all you come to learn from our article. 

Frequently Asked Questions:

These are able to amplify the audio signal by concentrating all sonic energy. It first collects the large dish at a focal point. The unique geometry of the paraboloid shape has made the concentration.

  • Q. What is it used for?

People use them on the sidelines of televised football games. Besides, ornithologists use them to record bird calls.

  • Q. Can it hear through walls?

Glass and walls block sound waves. So, it is impossible to hear sound for parabolic microphone through walls.