Ribbon mics are unique recording devices that originated in the 1920s. Used for a wide range of audio-related purposes, they continue to be a popular choice amongst musicians and audio engineers today.
How much gain do ribbon microphones need?
Ribbon microphones need at least 65dB of gain to work. Unlike standard dynamic microphones, ribbon mics require a more significant amount of gain to operate. This is because they are low-output devices. Other factors that impact the amount of gain that a ribbon mic needs, is whether the microphone is of the passive or active variety.
Both versions deliver the same, classic ribbon sound quality and detail, but their gain requirements vary. Active ribbon microphones require less gain than passive models and therefore can be used with your average audio interface rather than a specific high-gain preamp.
I’ll explore this and more in this detailed guide.
Ribbon Mics And Gain
Although ribbon mics are closely related to dynamic microphones, they have been categorized as a different device altogether. The reason for this is that they produce a much lower output than your average dynamic, or condenser mic.
A staple of professional recording studios since the 1920s, ribbon microphones have stood the test of time.
They’re highly versatile, and can be used for a wide range of recording purposes like vocals, acoustic instruments, amplified guitars, and perhaps most commonly, drum overheads.
If you’ve ever used a standard dynamic microphone for recording, you’ll know that all is required to capture the audio is to simply plug the mic into the preamp input on your audio interface, set the levels, and hit record.
Condenser microphones are also pretty simple to use. They require +48v phantom power, which is included on almost all interface preamps and mixers. You turn on the switch and the additional voltage is supplied to the microphone.
For more information on what a ribbon microphone is check out my article on this subject here.
Ribbon microphones must be connected to a device called a preamp before they enter the audio interface’s input. This preamp must be capable of supplying the ribbon mic with adequate gain, otherwise, it won’t perform to its fullest potential.
Ribbon preamps offer a significantly higher maximum gain than a standard preamp device. They are designed specifically to accommodate the low-output nature of ribbon mics. A standard preamp is likely to produce around 60dB of gain, while a ribbon preamp needs to exceed that amount, reaching at least 65dB and ideally upwards of 80dB.
The table below shows the optimal gain of popular microphones:
|Mic Type||Balanced/Unbalanced||Optimal Gain|
|Ribbon mic (passive)||Unbalanced||65-80 dB|
Ribbon Mic Preamps
As music production and audio recording have become more accessible, preamps have enjoyed a massive spike in popularity. These recording devices essentially prepare the audio signal before it reaches the audio interface or mixing desk.
You can get preamps for all kinds of specific purposes. There are preamps designed especially for snare drums, bass guitars, vocals, and every other recording application you can think of.
Your average multi-purposed preamp will offer a maximum gain of around 60-70dB. This amount is sufficient for the majority of recording devices, microphones, line-level instruments, and so on.
However, passive ribbon mics have very low outputs compared to the aforementioned devices.
If you use them with a standard preamp, it’s likely to produce noise issues because the preamp will struggle to supply the mic with adequate gain. This could ruin the precise, warm tone of the ribbon mic recording.
Since the gain of most preamps peaks at around 60-70dB, the ribbon mic will force the preamp to max out its gain. Although this may allow the ribbon mic to record audio, the overall quality will suffer and there is likely to be an abundance of unwanted hiss and buzz depleting the signal quality.
That’s where specifically designed ribbon mic preamps enter the picture.
These devices are often capable of producing upwards of 80dB of maximum gain, which is enough to power the vast majority of passive ribbon mics.
The result of having enough gain at your disposal for the ribbon mic’s requirements will be instantly noticeable in the quality of the recordings it produces. There will be no unwanted noise caused by the preamp struggling to supply enough gain for the ribbon mic to operate.
Indeed, there are some exceptional cases where using a passive ribbon mic with a standard preamp will work just fine.
Nevertheless, it’s better to not risk the sound quality of your recordings and to ensure that the mic is getting ample gain to operate to the best of its ability.
The three main qualities to look for in a ribbon mic preamp are:
- High gain (75dB+)
- Low noise
- High impedance
Ribbon Microphone Safety Measures
Ribbon mics have a reputation for being particularly fragile and delicate, and rightly so.
Whereas dynamic and condenser microphones are quite roadworthy and unlikely to be damaged by general usage, you need to take extra care when using a ribbon mic.
Thankfully, supplying the microphone with too little or too much gain will not damage it. All that this will do is negatively impact the overall quality of the recordings.
However, inside the microphone, there is an extremely thin ribbon material that is positioned in a magnetic gap. This material is integral, and if it is damaged the microphone will be rendered completely useless.
To give you an idea of just how to think that ribbon material is, on most vintage ribbon mics it is somewhere between 0.5-4 microns, which is 50 to 100 times thinner than a single human hair!
It’s important then, to protect this thin ribbon from damage.
- One of the most common ways that damage occurs is through using the ribbon mic with phantom power.
Many people confuse ribbon mics for condensers, due to their similar, bulky, vintage design.
If a ribbon microphone is subjected to the additional +48 volts of phantom power, this can completely fry the ribbon and wreak havoc on the inner components of the microphone.
Consequently, it’s important to always make sure that your preamp and audio interface aren’t supplying phantom power to the input that the ribbon microphone is connected to.
Active vs. Passive Ribbon Microphones
Active ribbon mics are a more recent invention than their passive equivalents and were designed to alleviate many of the potential worries I’ve outlined in this article.
Whereas passive ribbon mics ideally need around 80dB of gain to work effectively, active ribbon mics don’t need nearly as much. The advantage of this is that it makes active ribbon mics compatible with a wider range of preamps and audio interfaces.
Instead of needing to pair your ribbon mic with a specifically designed, high-gain, low-noise, high-impedance preamp, you can use almost any device with an active ribbon microphone.
Active ribbon mics, including the legendary AEA N8, N22, or A440 are much more flexible than their passive equivalents. The reduction in their need for gain means that there’s less chance of the recordings being tarnished by noise issues because the preamp won’t need to struggle to supply optimal power.
You might be wondering, why doesn’t everyone just use active ribbon mics so that less gain is required?
Although this may seem like a more convenient and logical option, passive ribbon mics are considered by many to be superior in other areas.
Vintage analog recording equipment is still regarded as the gold standard, even with all of the impressive advancements in digital recording gear. Passive ribbon mics were first introduced over a century ago, and they are capable of recording audio in a way that no other microphone can replicate.
Passive ribbon microphones tend to record with more clarity and warmth than their modern active counterparts. Indeed, tone and sound quality are two subjective topics that can’t be directly measured, but this is the general opinion amongst musicians and professional recording engineers.
So essentially, if your ribbon microphone is of the active variety you don’t need to overthink the amount of gain that it is being supplied with.
Provided the preamp and audio interface that you are using are of a decent standard, you should be able to plug in and get to work right away.
If your ribbon microphone is passive, you’ll need to follow the instructions outlined in this guide.
As a minimum, you should pair it with a ribbon preamp that is capable of providing it with 65dB of gain. Ideally, you should choose one that offers upwards of 80dB of gain to get the best results!
Check out this popular YouTube video on recording vocals with a ribbon microphone.
How does a ribbon mic work?
Inside the microphone, there is a thin metal ribbon that is suspended between two poles of a magnet. The ribbon vibrates, which creates a voltage that changes depending on the air pressure of the sound source.
What polar pattern do ribbon mics have?
Ribbon microphones are naturally bidirectional. This means that they have a figure-8 polar pattern, and are capable of recording audio equally from both sides of the microphone’s capsule.
Can you use ribbon mics for stereo recording?
One of the most useful things about ribbon microphones is that they are naturally capable of capturing stereo audio. The figure-8 polar pattern offers off-axis rejection, which makes this possible.