Microphones: A Definitive Guide To Really Good Ones*
The 3rd Breathtaking Edition of the "Getting Audio Into Clubhouse Series"
*This article will be in no way definitive. This article is written so that my wife and co-host Dr.Carlene MacMillan will perhaps start to appreciate why our Clubhouse show audio sounds so good. We hope it is useful to a general audience and audiophiles alike.
This article begins with a thank you to fellow creative Brian Penny, who both encouraged me to go to the NAMM audio equipment show and more or less made it happen. Fist-bump! Plus his creator economy commentary is generally spot on.
Our first reviews featured the the iRig2, made by IK Multimedia. With this tool, we now have the “highway to the danger zone” that is an Audio Cable capable of bringing any audio—even really good sounding audio—into Clubhouse and other social audio apps.
Today we talk microphones (With a focus on their use in social audio)!
In order to talk about microphones, it’s important to talk about the sound we are capturing:
For our purposes “Low frequency” sound is anything below 200 hz, low mid range Lives between 200–600hz, mid range is 600-2,000 hz, upper mid range 2 kHz to about 6kHz and high end anything above that.
Human hearing is between 20hz and 20,0000 hz, and that is the range reproduced by compact disc audio for example. On any given day the upper range of a persons hearing it is likely to be less than 20,000 Hz particularly as they get older, and can actually change over the course of the day given the fatigue your ears experience from hearing louder noises (or longer “listening sessions.“)
Sounds are fabulous! The human voice in conversation can be so pleasing!
But what shall we ever plug into the 1/4” jack on our iRig 2 to blow the minds of our followers? A professional microphone to capture the human voice of course! But, being a fancy professional microphone, it will need to be amplified. Keep this fact in mind, as it is important when we think about our microphone choices
There are at least four different types of commonly used microphone designs, and I will review the basics, along with some typical (and excellent) examples, in the following articles.
Dynamic microphones
Ribbon microphones
Small diaphragm condenser microphones (this is what is in your phone, by the way)
Large diaphragm condenser microphones
The first two do not require power The second two do.
And Now, Onward to Microphones:
The oldest microphone technology is known as the dynamic microphone: these require no power from their cable, and will ignore power if it is present.
A Brief Note on Power:
The power that runs down microphone cables at 48 V is referred to as "phantom power" — microphones that don't need it will ignore it. The one exception is the older generation of ribbon microphones, which will blow up if phantom power is applied. Don't do that. Don't ever do that. You'll make every audio engineer ever roll over in their grave.
Modern microphones do not explode when phantom power is applied.
How Dynamic Microphones Work:
These dynamic microphones have a diaphragm move when air vibrates, and this moves a magnet in an electric coil, and thanks for the science of Michael Faraday's law of induction, a current is generated when the magnetic field changes rapidly thanks to the vibration of the associated membrane in the air.
Since dynamic microphones have no active electronics, they require more signal amplification, which we call “gain” in audio land. Powered microphones like the condensers described below require less.
There is no “free lunch” when it comes to electronics, either you make something louder at the source, or you have to make it louder with an amplifier later, and all amplifiers introduce and increase noise. Expensive ones introduce little noise on average. Cheap ones are noisy.
Proximity Boost:
Anyone who has ever been behind a microphone knows that if you get closer to it, your voice is going to get louder. There is also going to be an increased amount of bass (low frequency content in the range below 200 hz) present in the signal. This proximity boost in both volume and bass frequencies is often desirable, but sometimes can be a bit much. Low frequency sound can carry a lot of energy, but can make things sound pretty woolly pretty fast. Many microphones and preamplifiers have a “low cut“ filter built-in, which allows us to roll off frequencies that would contribute mud to the sonic landscape. These low cut filters are, I promise you, your friend. Most of them are fixed at a frequency like 80hz. The really snazzy ones are variable frequency so you can choose where to roll off.
The reason I include this in the dynamic microphone section is these are particularly an issue with dynamic microphones, but are a still an issue across almost all microphone design. Some Omnidirectional microphones, like the earthworks line, do not have a meaningful proximity boost.
Ask Your Doctor If a Dynamic Mic Is Right for You
The first thing to do is to listen to what your voice sounds like when being captured by a microphone. Different voices sound better or worse through different microphones. This is why there is not just one best microphone for us all.
However, there are some features of dynamic mics that makes them better in certain use cases. First among them is that they tend to be quite durable. I have dropped my SM58 microphones more times than I can count, and so have more artists than you can imagine. Almost all of those microphones still work afterwards. This is not something that can be said for other pieces of technology.
Dynamic microphones also tend to pick up less background noise because they are not as sensitive as other microphones. So if you are recording in a less optimal environment, these can be more forgiving because they won’t pick up every bit of background noise.
The less good your acoustic environment, the more likely a dynamic mic will be a friendly choice. More to the point, dynamic microphones tend to be less expensive, and thus you can afford to get one and try it out without having to worry about rent.
Most dynamic microphones don’t have extremely “extended” high frequency range, which is to say they don’t pick up much beyond 12 or 15,000 Hz. This is bad if you’re recording an orchestra, but for capturing the human voice for the purpose of something like social audio, where the bandwith is limited by the compression on the software anyway, this is not a problem. I might argue it is a feature!
The other important point to consider is that when it comes to audio, the price-to-quality ratio is one of vastly diminishing returns. $1000 for a microphone maybe 10% better than a $100 microphone, but a $10,000 microphone will be maybe 1% better than $1000 microphone. And a $30,000 microphone will be 0.5% better than the $10,000 microphone. Therefore, a wildly expensive microphone will give you less chance to be a great fit for any particular speaker or singer than a small selection of more reasonably priced options.
Dynamic Microphones:
The Classic “Budget” Mic: Shure SM58 ($99)
This is the most utilized vocal microphone in professional audio, particularly in the live setting. It does not suck. It will never suck. It will always sound relatively good. It's never going to completely remove your socks, but it will never let you down. It is the Rick Astley of vocal microphones. Reliable, but not to be confused with the best. I have literally had to substitute a SM 58 for a Neumann microphone on a Steinway grand piano during a mission critical recording when one of my mics died. Do you know what? The piano sounded fine.
One of the "pro tips" regarding the SM58 microphone, so named because it was introduced in 1958 and hasn't been particularly changed or updated since then, is that if you have an especially high quality preamplifier, you can actually rip the transformer out of the handle of the microphone and wire the capsule directly to the output. This reduces the output gain by about 20 db but sounds much more “open.” The other workaround for this is substituting that transformer with one manufactured by TAB-funkenwerk (or if you're a sane individual having that done preemptively by the folks at Zen Pro audio or Crimson). This upgrade makes it sound hell of a lot like its big brother, the SM7b, described next.
The Shure SM7b ($399)
Much of what you hear of one particular frontier psychiatrist is captured through the SM7b on the regular. You’ll also spot in many of the videos by top YouTubers.
Other contenders in the world of “broadcast quality” dynamic mics include the electro voice RE20.
The SM7b picks up little background noise, is flattering on the voice, doesn’t get too bass heavy, and with the included thicker pop filter situation in place, has really nice control of excessive plosive sounds.
Paired with a really high end microphone preamplifier and you have the sound of the vocals on many pop records. (Iron Age Audioworks was my 2021 NAMM favorite new pre!)
