Today we are going to introduce a device that most people rarely touch (except in recording studios and movies), it is a ribbon microphone. Although many guitar players rarely touch it, it is an indispensable equipment in recording. Next we will explain why, but first...
About the history of ribbon microphones
The microphone has not been unfamiliar since the advent of the telephone. The first microphone was carbon mics. When the sound wave vibrates, the pressure generated by the sound of different intensities will be different, which will cause the contact resistance between the carbon particles to change and generate a current signal. Although a person who went to space and the moon once used this kind of microphone, it is undeniable that the frequency response of carbon microphones is poor. Therefore, until around 1970, its use was limited to the use of telephones.
However, a long time has not passed, and there has been a competitor for carbon microphones. Crystal mics, just like its name, are indeed applied to crystals. It continuously pushes the crystal in a way to generate electricity. But it is worth noting that although the recording effect of the crystal microphone surpasses the carbon microphone, we still would not use it on the stage or in the recording studio, because it still cannot capture the beautiful sound quality.
Electric microphones, also known as dynamic microphones (Dynamic mics) are undoubtedly one of our standard equipment when recording. Its capture sound quality is good, the coverage is comprehensive, the operation is relatively simple, and it does not need to spend a lot of money to make. Electric microphones and audio have the opposite focus. For electric microphones, the most important structure is a circular coil as a conductor, glued to the diaphragm that receives sound waves, and suspended in the magnetic gap of the magnetic circuit system. When the coil vibrates under the action of sound waves, it will move back and forth and thus generate electromotive force, which becomes the analog signal of the sound source. Therefore, most electric microphones have good recording effects and are cost-effective.
How many people have heard of Walter Schottky? He is known to the world mainly for inventing the diode named after himself. However, he and his partner Erwin Gerlach invented the ribbon microphone in the early 1920s. His invention is now an indispensable device in the recording industry, and his diode design is more widely used in high-quality electrical appliances. At the end of the twentieth century, the application of the lotus socket (RCA) promoted the commercial development of ribbon microphones. And now, many high-quality and even collectible ribbon microphones are still in use. So how does it work? Aluminum ribbon microphones usually put an aluminum ribbon metal film-very thin, about 0.015 mm. When the film is vibrated by sound, it will receive a signal due to electromagnetic induction and generate an electrical signal.
Working principle of ribbon microphone
Although it is possible to replace the ribbon in the microphone by yourself, I do not recommend this because it is very likely to break into two pieces in your hand. But if you really want to improve the sound quality of the microphone by replacing the aluminum band, you must do it carefully.
The electrical signal transmitted by the ribbon microphone is different from that of the dynamic microphone, but from a technical perspective, the ribbon microphone is one of the dynamic microphones. There are many obvious differences between old ribbon microphones and modern designs. The old design has a lower acoustic impedance (impedance), in most cases 0.2 ohms. This value is too low, so that we need to increase it in actual use, this time we will use a transformer (transformer).
Transformers are sometimes confusing. In a guitar amp, people can easily distinguish the gap between an ordinary transformer and a sophisticated transformer; the same is true in the use of a microphone. If you are not confident that you can successfully replace the aluminum ribbon in the microphone, then you can consider using a higher-quality transformer to improve the effect of the microphone. If you want to maintain a low degree of distortion, the transformer you choose may be very expensive.
Condenser microphones (hereinafter referred to as condenser microphones) require a polarized power supply, but ribbon microphones do not. If an old-fashioned ribbon microphone is connected to a preamp designed specifically for electric microphones, it will automatically connect to a polarized power supply and cause irreversible damage, and this must be kept in mind! Most preamplifiers have a button that can select the polarized power switch, so watch carefully when using it.
Use points: Many ribbon microphones will be severely damaged when they encounter phantom power. Always remember to check whether the power switch is turned off before recording and mixing. Some ribbon microphones in recent years have added settings that can prevent such mistakes, but you must read the manual carefully to confirm.
When it comes to preventing such mistakes, there is another important difference between the old and recent ribbon microphones, which is their durability. There are some old-fashioned ones that may have excellent recording effects, but are not strong and fall-resistant. But what is confusing is that they can tolerate extremely high sound pressure levels (SPL). The ribbon microphone can work in a high sound pressure level environment, but when facing a loud singer, you need to consider preparing a blowout cover. In fact, we should equip the microphone with a blowout cover all the time, especially when moving the microphone. In any case, do not shout into the ribbon microphone or blow into it, this must be remembered.