Royer R121 studio ribbon microphone.
A lot of people ask: do I need a ribbon mic? If you’re asking that question, you’ve probably got at least one microphone already: perhaps a large-diaphragm capacitor mic or a dynamic mic such as an SM57. You’ve heard about this special type of mic called a ribbon mic and you’re wondering if getting one is going to make a big difference to your recordings.
Do You Need A Ribbon Mic?
Well, I think that for a lot of people, a ribbon mic does offer something usefully different from a typical capacitor or moving-coil mic. You can also get good ribbon mics quite affordably, so yes, they can often be a good choice if you’re looking to expand your options. However, I think the reasons for that aren’t always well understood.
The mics that we’re most familiar with tend to be uni-directional. That is, you point them at something, and they pick up sound very well from the front, less well from the sides, and quite badly from the back. That’s called a cardioid or heart-shaped polar pattern. That’s a very useful way for a mic to behave, and it seems very natural, but actually it isn’t.
...a ribbon mic does offer something usefully different from a typical capacitor or moving-coil mic.
There are only two fundamental ways for a microphone to behave. One is for it to pick up sound equally from all directions. That’s called an omnidirectional polar pattern. The other is to pick up sound equally from the front and back, but reject sound coming from the sides. That’s called a figure-8 polar pattern. If you want to create the unidirectional pattern that we’re familiar with, you have to adapt one of these fundamental patterns. That requires some very complicated acoustic engineering, and it’s all a bit of a compromise.
Figure-8
What’s distinctive about ribbon microphones is that they are fundamentally figure-8 mics. They pick up sound from the front and back and they reject sound from the sides — and the key point here is that they do the rejecting part really, really well.
So if you have two sound sources in a room and you want your mic to capture one of them and ignore the other, a figure-8 mic will do that much better than a uni-directional one, if you get it in the right place. The classic example is when you’re recording someone who sings and plays acoustic guitar. If you use a figure-8 mic positioned something like this, you can capture the guitar whilst picking up hardly any vocal.
Another example is that if you are in a room with a low ceiling, you generally want to avoid picking up reflections off that ceiling. Use a ribbon mic and keep it upright, and it’ll hear the source and whatever is behind it, but not what’s bouncing off the floor and ceiling. So, on the one hand, you do need to be careful about what’s behind the mic, but on the other hand, a ribbon mic has much greater power to ignore things that you don’t want to hear than conventional mics do. Also, it you ever want to try out the Mid-Sides stereo miking technique, you will need a mic that has a figure-8 pattern for the Sides mic, and ribbon mics are perfect for that.
Ribbon Mic Sound?
People also say that ribbon mics have a distinctive sound, and that can be true, and it’s partly linked to the figure-8 polar pattern. You’ll probably have noticed that if you use a directional mic very close up, you capture a lot more bass. If you speak really close to the mic, you’ll get that Hollywood trailer voice with tons of bottom end on it. That phenomenon is called the proximity effect and it’s even more pronounced in a ribbon mic. As soon as you move a ribbon mic within two or three feet of the source, you begin to get this bass rise, and that’s part of the reason why they’re perceived as sounding warm.
Rode NTR ribbon microphone.Another reason is that, historically, ribbon mics did often have a limited high-frequency response compared with capacitor mics. However, that doesn’t have to be the case, and a lot of modern designs have very extended high-frequency response. The image shown here is a Rode NT-R, for example, and it’s flat to something like 22kHz. But a lot of people still believe that ribbon mics sound smoother than capacitor mics, or that they ‘take EQ well’, and there is some truth in that.
A capacitor mic element is constructed a little bit like a drum, with a circular membrane tensioned across a ring. Like a drum, that resonates, and because it’s small and light, the resonant frequencies are mostly in the 10-20 kHz range. So high-frequency sound can set off these resonances that we musicians hear sometimes as a desirable sparkle or excitement and sometimes as harshness or artificial brightness.
Ribbon Mic Element
The element in a ribbon mic is a piece of very thin metal foil suspended in a magnetic field. That also has a resonant frequency, but this is at the other end of the frequency spectrum, and is deliberately set to be below the frequency range that we can hear — perhaps 10 or 20 Hz. So the top end doesn’t have any of these resonances that are characteristic of capacitor mics, and thus sounds smoother.
What About Any Down Sides?
So ribbon mics are really useful, and they are usefully different from other types of mic. What are the down sides?
- Well, there’s a perception that they are very fragile. I think people actually make too much out of that. If you treat a ribbon mic the same care you’d treat any other mic costing hundreds of pounds then you’ll be fine. The main thing to avoid is air blasts that would stretch or break the ribbon, so don’t use them outside, don’t put them inside a kick drum, and use a pop shield if you sing close up into them.
- There’s also a perception that ribbon mics have very weak output and need a lot of gain from the preamp. Again, that’s largely historic. Modern ribbons use rare-earth magnets that are much stronger than the ones available in the 50s, and and the level should be at least comparable to what you get from a moving-coil dynamic mic. If that’s not enough then you can get active ribbon mics. These have a phantom-powered buffer or preamp circuit in them and put out the same sort of level as a typical capacitor mic. Again the Rode NT-R is a good example.
Which Ribbon Mic Should You Get?
Well, the ribbon mic is inherently quite a simple device, so you can get a perfectly functional one relatively affordably. However, the thing to watch out for with cheap ribbon mics is quality control.
The all-important ribbon element needs to be made out of very thin foil and it needs to be tensioned and positioned very accurately within the magnet gap. On super-cheap ribbon mics that isn’t the case, they use foil that’s too thick and it won’t be properly tensioned. So although you don’t have to spend thousands, it is worth buying from a reputable brand — I wouldn’t recommend getting some sort of no-name Chinese knock-off. And if you do spend thousands, you can get a very nice mic indeed!