What Is A Dynamic Microphone
A closer look at the most commonly used microphone type
Within the world of microphones, each variety has benefits and drawbacks depending on the application. Condenser microphones often work best in a studio setting on account of their sensitivity to a wide range of musical frequencies, however they require a power source and are often more fragile than other mics so aren’t best suited to a life on the road. Dynamic mics, on the other hand, are usually more ruggedly built, heavier and better equipped to cope with capturing much louder noises like guitar amplifier cabinets. There is no ‘best’ microphone type, it all comes down to how you’re going to use it.
It’s worth examining in a bit more detail the characteristics of dynamic microphones, considering how prevalent they are. Whereas the condenser mic is generally made with the recording of specific sounds in mind, dynamic microphones are the more all-round solution for many a situation. Consider the mics used in public address systems, at speaking events, at press conferences. We’d wager 99% of the mics you see used in these situations would be dynamic, but why is that? What is a dynamic microphone? Let’s look at some of the technical foundations, as well as comparing and contrasting some of the individual characteristics and what it is that makes them so versatile.
The science bit
Ok, first a disclaimer. We’re not scientists or engineers, so we’ll try and explain things in a pigeon way which even our non-science brains would understand. Basically, a dynamic microphone works because of electromagnetic induction. The microphone’s capsule consists of a piece of wire coiled around a magnet, with a diaphragm sitting at the top. The diaphragm vibrates as it picks up sound waves, which in turn causes the coil to move which, in turn, creates an electrical signal from the magnet. This signal then passes through the microphone to create a signal, which is converted into a sound when it reaches its destination, i.e. an amplifier or recording device.
Benefits of going dynamic
Compared to a condenser microphone, a dynamic can come across as its rough-and-ready, uncultured cousin. Unlike a condenser, which are slightly more fragile and often never see beyond the four walls of the studio, dynamics are usually pretty robust. This extra weight and rigidity makes them ideal for taking out on the road, where they could be dropped, smashed into, had pints poured onto them etc. Ok, maybe that last one would be a bit much but still.
They’re also easier to integrate into small setups, on account of them not requiring their own power source. Condenser microphones work by having a small electrical current charging up its capacitor, and this charge requires it to have its own power. You may have seen the term ‘phantom power’ used in a studio – this is the practice of supplying a condenser mic with the small amount of juice it needs to operate. Dynamics don’t have this requirement, and can be plugged directly into an amplification source, or a recording setup.
Another benefit is that dynamic mics are happy enough having high volumes of sound pumped into them. It could be a wall of 4×12 guitar amplifier cabinets, or it could be drum kit; either way, a dynamic can cope with extreme volumes better than other microphone types. Conversely, for capturing more delicate sounds, or instruments with higher frequency outputs like cymbals or string instruments, it would make better sense to use something more sensitive like a condenser.
Drawbacks of a dynamic
While yes, it is perhaps the most versatile microphone and is well-suited to a number of different applications, there are certain unique characteristics which are worth considering. First of which is the cardioid pickup pattern, which means the mic is best at picking up a signal from one specific direction, as opposed an omni-directional pickup which picks up the entire sound in its vicinity. This has a noticeable side-effect with dynamic mics, whereby recorded sounds – particularly vocals – can appear bass heavy. For this reason, many mics with this particular pickup pattern come with a built-in EQ shelf to compensate for the boosted lower frequencies.
There’s also a slightly different frequency range which a dynamic can pick up, compared with other microphone types. Frequencies above a certain level, i.e. just under 20 KHz, aren’t usually recognised by the mic, meaning instruments which sit at the higher register (e.g. certain harmonics from acoustic guitars) are captured as accurately as they would be using a condenser microphone. It’s horses for courses though; for basic recording and demo production, you’ll unlikely miss those extreme high frequencies, but for recording that once-in-a-lifetime take, it may be better to consider a different type of mic.
It’s easy to assume the humble dynamic mic is a hardworking but limited tool with which you’d happily travel the world, but wouldn’t trust to get those ultra high quality studio recordings. And, to a point, you’d be right. But realistically, the market for said ultra high quality recording is limited largely to pro and semi-pro musicians, and the prices at the higher end of the condenser market would make your eyes water. But for reliable, every day use you’d be hard pushed to find a more versatile, trustworthy tool than a good quality dynamic microphone. One such example, the most obvious, indeed the most used microphone in the world, is the famous Shure SM57. If you’ve been under a rock for the past 50 years and don’t know what these can do, then you owe it to yourself to check one out. Put simply, they are the industry standard dynamic microphone, and should be one of the first investments of any budding record producer or sound engineer. Never has a piece of gear so clearly defined its own class so comprehensively. Even on the biggest selling records in history you’ll often find a bog-standard SM57 tasked with recording everything from guitar amps to synths, and from vocals to foley. They’re not expensive, relatively speaking, and you can bank on them lasting for years to come.
We hope the above article went some way to describing what is a dynamic microphone. If you have any more questions, our in-store product specialists would be happy to help.