Contrary to what most of us believe when getting started, recording actually involves as much art as science. It takes time to master the skills and techniques that produce the best results. There are certainly different microphones to be used for recording, and there are key advantages as well as disadvantages to each one.
Dynamic mics are a great benefit to recording instruments and, in some cases, vocals, but it’s crucial to understand the various components that go into determining which one is optimal at any given time.
What Is a Dynamic Mic?
Most people, when they think about a microphone, are probably envisioning what a dynamic mic is. Most stage microphones for vocals and instruments are dynamic mics.
A dynamic mic utilizes a thin copper wire coiled up and a razor-thin diaphragm, often made of mylar, stretched over the wire. The copper wire is suspended among a magnetic field and as the coil shifts up and down in response to sound, and as the diaphragm vibrates, it creates an electrical current that is then transmitted down the line to speakers or a recording track.
When to Use Dynamic Mics
Dynamic mics are commonly used in a wide range of settings. They are the most common choice for live performances. They are used to pick up the sound of a percussion section (like a drum kit), to supplement guitar and bass amps and move that sound through the main PA system, for vocals, and a host of other purposes.
In a recording environment, dynamic microphones are commonly used to mic up drum kits, guitar speakers, and even brass and woodwind instruments. Rarely will dynamic mics be used to record lead or even harmonizing vocal tracks in a studio setting, but there are times when people prefer these mics for voice over condenser mics.
Why Use Dynamic Mics at All?
Condenser microphones are incredibly powerful and sensitive. The clarity that can be produced using condenser mics is simply unmatched by most dynamic mics due to the construction and materials used (not to mention the source of power needed for high-end condenser mics).
That doesn’t mean condenser mics are optimal in all recording situations, settings, or environments. In fact, dynamic mics are most commonly used for studio recording outside of vocal and acoustic guitar tracks.
The reason for this has to do with noise. Because condenser mics are so powerful and sensitive, they will generally pick up almost every sound that enters its sphere. Even in a closed, soundproof recording room, using a condenser mic to record an electric guitar means it will pick up the whirring of the fan inside the amp, the strumming of the strings, a tapping of the player’s foot, and more.
Dynamic mics are less sensitive than condenser microphones for sure. They are also unidirectional, which means where the microphone is aimed is where its focus is. Positioning a dynamic mic over a snare drum means, when it’s positioned properly, it will pick up that particular drum primarily. Due to the nature of percussive sounds, though, there will be what’s called ‘bleed’ or ‘bleed through’ on those recordings. In other words, the dynamic mic is still going to pick up other heads and cymbals, but its primary focus will be on the snare, in this example.
Dynamic Mics Have a Lower Frequency Response
This is a fancy way of saying dynamic microphones are not going to pick up the high-end frequencies nearly as well as condenser mics will. That can be problematic for vocals and some other tracks, but in most cases, it’s actually a benefit.
Electric guitar amps, bass setups, drums, and even some brass and woodwind instruments will naturally produce ringing or echo from within the speaker box (guitar), drum shell, or even the saxophone or other brass instruments itself. A condenser mic, because it’s so sensitive, will be picking up all of that extra ‘noise.’
A dynamic mic won’t. That produces less harshness in the recording, whatever instrument is being recorded at that time.
Limitations of Dynamic Mics
One key complaint that some recording artists have about dynamic mics is that they don’t have nearly the same power as condenser mics. They are weaker, in essence. This isn’t often a problem for instruments that can produce high volume sound, but for softer, quieter tones and instruments, like a flute or oboe, for example, a preamp may be necessary to give it a boost.
De-Essing Becomes Less Necessary
For individuals recording webinars, podcasts, or other home-based projects, a condenser mic can be optimal, but it will also maximize a problem known as ‘essing,’ or emphasizing the S’s and T’s of spoken or sung voice. De-essing can sometimes be done after recording, usually with plug-ins to the recording software, but it’s often limited in its scope.
Dynamic mics limit the amount of de-essing that may be necessary after the recording is complete. These S’s and T’s are captured along the higher end frequencies, so dynamic mics because they don’t pick up those same frequencies as well as condenser mics, won’t pose the same challenges.
Cost Advantages of Using Dynamic Mics
In days of old, condenser mics were incredibly expensive, especially those that would most commonly be found in professional recording studios. Today, thanks to innovation and the decreased cost of producing these mics, they are more comparable to other mics.
Still, dynamic microphones are commonly far less expensive, quality to quality, than condenser mics. That means a small home studio could purchase several decent quality dynamic microphones for the cost of one condenser mic.
Depending on the specific needs of the individual, one or two dynamic mics may be all that’s needed. However, if drums will be recorded, it is optimal to have at least one dynamic mic for every drum head and two for overhead. Some personal home studios may mic up the kick (with a special dynamic mic designed to absorb the thrust of air generated by a kick drum), snare, one mic for two overhead toms, and one to capture the remaining toms (including the floor tom). It would also be advisable to use another dynamic mic for the high-hat. All other cymbals can be picked up by two overheads if microphones are in limited supply.
The positioning of Dynamic Mics for Recording
For drums, dynamic mics should be positioned as close to each respective head as possible without coming in contact with it. Utilizing special mounting kits designed specifically for drums would be ideal. The mic for the kick drum, if it contains a hole in the outside skin, should be positioned just at the entry point, but not too far in.
For guitar and bass amps, the dynamic mic should be positioned not in the center of the speaker, but along the skin, toward the outside edge of the actual speaker. For brass and woodwind instruments, the mic should be positioned several inches outside the main horn or exit point of sound, and not so far away that external noise could impact quality.
If recording voice or vocals with a dynamic mic because of background noise issues, use a popper stopper and encourage the individual to position his or her mouth no more than a few inches from the center of the mic.
Dynamic mics are certainly going to be optimal for recording many instruments, but unless there’s a serious background noise concern or issue, these mics will never offer the level of clarity and quality for voice or vocal recording that condenser mics can.