Dynamic microphones aren’t just a poor man’s substitute for a higher-end mic. In fact, many dynamic microphones are legendary in their own right, and they’ve been used on countless hit records for guitar cabinets, drums, and even lead vocals. Dynamic mics are renowned for their rugged construction, and they can handle everything from cranked guitar amplifiers to screaming metal vocalists without breaking a sweat. Beyond that, the sound of a high-quality dynamic microphone might simply be the exact sound you’re searching for. While the large-diaphragm condenser mic is arguably the centerpiece of most professional studios, you’ll find nary a high-end facility without a massive cache of dynamic microphones at its disposal — they’re simply too useful to ignore.
Anatomy of a Dynamic Microphone
Dynamic microphones work via electromagnetic induction. They employ a magnet that surrounds a small, moveable induction coil positioned inside that magnetic field, hence the dynamic mic’s common alternative name, “moving-coil microphone.” The diaphragm — a lightweight membrane that vibrates back and forth when sound waves hit it — is attached to the moving coil. As the diaphragm moves, these vibrations are transferred to the coil, causing it to move, as well. This results in an electric current at the microphone’s output. A step-up transformer is then used to increase the low-level signal to a mic-level signal.
Basically, a dynamic microphone operates just like a loudspeaker but in reverse.
Characteristics of a Dynamic Mic
Typically, dynamic microphones aren’t as sensitive and don’t deliver the same level of detail as a condenser mic. That said, if you’re working in a space with subpar acoustics, this could be a good thing. Beyond that, dynamic mics can withstand high-SPL sources, such as cranked guitar amps and snare drums, that would overpower a condenser microphone with less headroom. They’re also extremely robust and resistant to moisture, and they don’t require external power.
Beyond that, since most dynamic microphones feature a cardioid, supercardioid, or hypercardioid design, they possess a high degree of sonic isolation. A cardioid polar pattern is most sensitive to sound entering from the front. The sides offer moderate rejection, and the rear offers significant rejection. Supercardioid and hypercardioid mics offer more directionality than a standard cardioid but with less rear rejection.
Cardioid mics are great for recording vocals and other close-miked sources, while supercardioid and hypercardioid polar patterns are ideal for safeguarding against bleed from competing sound sources, such as hi-hats bleeding into a snare-drum mic.
To top it off, cardioid, supercardioid, and hypercardioid polar patterns offer excellent gain before feedback, which is a huge plus for live sound applications. Is there any wonder that dynamic mics like the Shure SM58 and Sennheiser e 825-S are used by vocalists on concert stages worldwide?
The Best Tool for the Job
There’s a common misconception that dynamic mics are inferior to condenser mics and that dynamic microphones have no place in pro-level studio applications. Not so! Dynamic mics are used in the studio — even in world-class studios — all the time for countless applications: drums, guitars, percussion, vocals, etc. What’s more, there are plenty of times when the humble dynamic mic is simply the best tool for the job at hand.
For example, the Sennheiser e 906 is an industry-standard guitar-cab mic. The AKG D112 is guaranteed to make your kick drum thump. The Shure SM57 is used so often for recording that most studios keep an entire stockpile of them in their mic locker. And why not? The SM57 is practically bulletproof, and it sounds great on anything! Want to learn more about the SM57? Check out this article.
Of course, there’s the now-legendary Shure SM7B, a top-shelf studio vocal mic if there ever was one. The SM7B sounds so good, in fact, that Quincy Jones and Bruce Swedien opted to use it on Michael Jackson’s lead vocals for his chart-busting Thriller album. Simply put, the SM7B is a $400 dynamic broadcast mic with a multi-platinum sound.
Another storied dynamic mic is the Electro-Voice RE20 microphone that’s been used on studio vocals, drums, and woodwinds for decades.
In-line Microphone Preamps
When dynamic microphones are used in studio applications, many engineers like to employ an in-line preamp, such as the Cloudlifter CL-1, between the mic and their console or microphone preamplifier. In-line preamps give you added gain, enabling you to get the best possible sound out of a dynamic mic, which is a low-output device by design. Deploying an in-line preamp will completely transform even the humblest of dynamic mics, yielding you clean, transparent recordings with less self-noise.
Conclusion
No matter what type of dynamic microphone you’re searching for, Sweetwater has your back. Give your Sweetwater Sales Engineer a call at (800) 222-4700, and we’ll set you up with the perfect dynamic microphone for your application and budget.