Welcome to the second part of our microphone guide.

In the previous guide, we looked at moving-coil dynamic microphones. This time we are looking at another microphone type which also works through electromagnetic induction but behaves very differently in practice: the ribbon microphone.

Ribbon microphones are known for their smooth sound, natural high-frequency response and distinctive figure-of-eight polar pattern. They can be extremely useful when a recording needs detail without sounding overly bright or aggressive.

Let’s start by looking at where they come from and how they actually work.

Before we start: microphone type and polar pattern are still not the same thing

As in the previous guide, the microphone type describes the transducer principle: how the microphone converts sound energy into an electrical signal. The polar pattern describes the direction, or directions, from which the microphone picks up sound.

Ribbon microphones are often associated with a figure-of-eight polar pattern because of the way the ribbon element is exposed to sound from both the front and back. However, not every ribbon microphone is necessarily a figure-of-eight.

So, again, keep these two questions separate: ‘How does the microphone convert sound into electricity?’ and ‘From which direction does it pick up sound?’.

A little history

Ribbon microphones became practical during the 1920s and 1930s and were quickly picked up in broadcasting and recording circles. The BBC-Marconi Type A ribbon microphone became one of the most recognisable microphones of British broadcasting and was widely used by the BBC from the 1930s onwards. One of the major pioneers was RCA (Radio Corporation of America), whose ribbon microphones became widely used in American radio and recording studios.
Models such as the RCA 44 and RCA 77 are iconic and the microphones remained associated with broadcast speech, orchestral recording and vocal work for decades.
In Europe, ribbon microphones were developed by manufacturers such as Beyerdynamic and later Coles. Ribbon microphones became especially valued for their smooth and natural sound at a time when recording systems could easily become harsh in the upper frequencies. Although condenser microphones later became more dominant in many studios, ribbon microphones never disappeared. In recent decades they have experienced a major revival and are now common in both traditional and modern recording setups.

How does a ribbon microphone work?

A ribbon microphone works through electromagnetic induction, just like a moving-coil dynamic microphone. The difference is that there is no separate diaphragm and voice coil. Instead, the microphone contains a very thin strip of conductive metal (the ribbon) suspended inside a magnetic field.

When sound reaches the microphone, changes in air pressure make the ribbon move backwards and forwards. Because the ribbon itself is electrically conductive, its movement through the magnetic field induces a small electrical voltage.

So the basic process is:

sound wave → ribbon moves in magnetic field → electrical voltage is generated

The ribbon therefore acts as both the moving diaphragm and the electrical conductor. This keeps the moving mass inside the transducer extremely low. 

What does this construction mean when recording?

The ribbon element is extremely light and can respond easily to changes in air pressure. This allows ribbon microphones to reproduce transients naturally while maintaining a smooth frequency response.

Unlike many condenser microphones, ribbon microphones are usually not designed to emphasise the upper frequencies. Hence they are often described as sounding warm, smooth or natural, and can be particularly useful on sources which would sound harsh or overly bright with other microphones.

The trade-off is that traditional passive ribbon microphones usually produce a comparatively low output and may require a considerable amount of clean preamplifier gain. Although many modern ribbon microphones are considerably more robust than older designs the ribbon element itself is physically delicate.

Advantages and disadvantages

Ribbon microphones can therefore be extremely forgiving on bright sources but they also require more thought about room placement and gain structure.

Where would we use a ribbon microphone?

Ribbon microphones are common in recording situations where a smooth and natural sound is preferred.

Typical applications include:

• guitar amplifiers

• brass instruments

• strings

• drum overheads

• room microphones

• vocals

• piano

• orchestral recording

• percussion

• woodwind

• broadcast and spoken voice

They are particularly popular on electric guitar amplifiers because they can retain detail while reducing the harshness which can sometimes appear in the upper midrange. Just remember, that strong blasts of air should be avoided because they can stretch or damage the ribbon.

Ribbon microphones are also commonly paired with another microphone type. For example, a ribbon combined with a moving-coil microphone on a guitar amplifier can provide a useful blend of attack, body and smoothness.

Why are ribbon microphones often figure-of-eight?

In a traditional ribbon microphone, both sides of the ribbon are exposed to the surrounding air.

Sound arriving from the front pushes the ribbon in one direction. Sound arriving from the rear pushes it in the opposite direction. Sound arriving from the side reaches both sides of the ribbon at almost the same time and therefore creates very little net movement.

This produces the characteristic figure-of-eight polar pattern with strong sensitivity at the front and rear and deep rejection at the sides. The latter can be extremely useful when positioning microphones because the side nulls can be aimed towards unwanted sound sources.

A famous exception is the Beyerdynamic M160. Unlike most traditional ribbon microphones, it uses a hypercardioid polar pattern rather than figure-of-eight.

 This makes the M160 a useful reminder that the ribbon transducer principle does not automatically determine the polar pattern.

Distance matters

Ribbon microphones often have a pronounced proximity effect because many traditional ribbon microphones come with a figure-of-eight polar pattern. Moving the microphone closer to the source can increase the low-frequency response considerably.

This can make a voice, guitar amplifier or brass instrument sound fuller and more powerful.

Moving farther away usually reduces this effect and allows more room sound to become part of the recording. Distance therefore has a major influence on both the tonal balance and the amount of ambience captured.

A note about phantom power

Traditional passive ribbon microphones do not require phantom power. Although some modern passive ribbons are designed to tolerate it, older and more delicate ribbon microphones can be damaged if phantom power is applied under faulty or unbalanced conditions.

For this reason, phantom power should be treated with care around ribbon microphones.

Active ribbon microphones are different. They contain active electronics and may require 48V phantom power.

If unsure, check the manufacturer’s specifications before switching on phantom power.

Some well-known ribbon microphones

Microphone	Typical use
	Historic broadcast, vocals and orchestral recording
	Broadcast, vocals, speech and studio recording
	Drum overheads, brass, strings and orchestral recording
	Guitar amplifiers, brass and instruments
	Guitar amplifiers, drums and instruments
	Vocals, guitar amplifiers, rooms and instruments

I hope this introduction to ribbon microphones was useful. If there are any questions, drop me an email.

In the next episode, we will look at condenser microphones: how they work, why they are generally more sensitive and why they are so common in studio recording.