You have this great voice actor, Mike Green, who you want to record for a radio commercial, audiobook, podcast, or audio drama. You just don’t know what microphone to use.
In the modern audio world, the word “microphone” is abbreviated “mic” but pronounced “mike” just like your talent. Also, the word “mic” is used as a verb meaning to record with a microphone as in “how should I mic Mike?” Thus the pun in the title of this post.
Oh so many . . .
If you search online for microphones you will see a huge number available in all price ranges from less than $100 to over $10,000. How to decide?
Realize that the microphone is part of a chain of tools that made up the recording process. This chain includes:
– the recording space
– the microphone
– the microphone pre-amplifier
– the analog to digital converter (assuming we want a digital recording)
– the mixing console (if more than one mic or recording channel is used)
– accessory gear used to do tasks like reduce exaggerated “s” sounds, prevent “pops” on certain hard consonants, reduce dynamic range, etc.
– the recording system used
– the editing system used
In other posts we will deal with each of these categories but in this post we will focus on the microphone. Understand that choice of microphone will be influenced by other gear in the chain, as well as by your budget.
This post considers microphones for the spoken voice. So if you are reading this hoping to figure out what mic to use to record your kick drum, or your church choir, or a piano then you are in the wrong place. The Audio Penguin, Eric Somers, is also a classical music tonmeister and thus uses some microphones for classical concerts that would not be the best choice for spoken voice. This post will focus on the mic needs of the spoken voice.
One can find whole books about microphones. The field can be quite technical. The Audio Penguin is going to provide a brief overview and suggestions based on the experience of the Penguin and The Sandbook Studio. If you want ten different opinions, then just talk to ten engineers. If you have experience or thoughts that are different, feel free to express them as a comment to this post. This is a moderated blog so all we ask is that your comments be courteous and focused on ideas. No spurious personal insults.
A microphone changes varying air pressure – sound waves – into varying electrical pressure: the audio signal that is sent to a recorder, console, speakers, etc. The part of the mic that does this is called the “transducer.” There are three basic kinds of transducers found in professional mics and I will summarize them here and briefly highlight the advantages and disadvantages of each.
The Dynamic Transducer (also called the Moving Coil transducer)
In this transducer the diaphragm (the thin flat membrane the sound waves strike as they hit the mic) is connected to a coil of wire that surrounds a permanent magnet. As the coil moves in the magnetic field a small electrical signal (the audio signal) is produced and sent to the microphone preamplifier. (All mics produce a weak signal and thus need a preamplifier, either separately or built into a console or recorder.)
The main advantages of the dynamic mic are that they are generally reasonably priced, work well indoor and outdoors (as they are not affected by high humidity), and they can take high sound pressures (such as a voice shouting or singing close up). Small diaphragm models are often used on stage or by news reporters outdoors.
Generally the “reach” of these mics is limited, meaning that one needs to talk close to the mic for best performance (3-8 inches). By talking close some low level background sounds are limited, making the mic good when one need to record voice in an environment with extraneous ambient sounds.
Although small inexpensive models are often used on stage and in the field when reporting news, many radio stations use larger dynamic models in broadcast booths for radio personalities and news interviews. Two very common mics are the Shure SM7 and the Electro-Voice RE-20 shown below. These are more expensive than the small handheld models but are still usually only $300-400 (prices may change after I write this, so check online).
The Capacitor Transducer (also called the Condenser Transducer).
“Condenser” is simply an old fashioned word for “capacitor” so it amazes me that so many mic manufacturers still call their capacitor mics “condenser” mics. I think about that every time I drive my motorcar to the aerodrome to take a flight on an aeroplane while listening to music on my wireless. The Audio Penguin will refer to these mics as “capacitor mics’ but be warned they might be called “condenser” mics in the store or online catalog.
This is the most common transducer for high end mics used in studio recordings, and even in many radio stations. The prices can vary from about $100 for Chinese made models (even for companies in the US and Europe) to about $12,000 for extremely rare models. Fortunately the highest end models go beyond what is probably needed for voice based production.
One person who promotes workshops on audiobook narration told me that no publisher or talent he ever worked with asked about the kind of equipment that would be used for audiobook recording. That, however, is not my experience. I know of a narrator who refuses to talk into anything other than a Neumann U87, probably the most ubiquitous microphone of the narration industry. As I write this the price of the mic at BH Photo Video in NYC is about $3200. It is such a standard that the high purchase price still makes it a good investment. I have even had the agent for a voice artist ask about the equipment I was using.
But one can do well for a lot less money. There are many Chinese made capacitor mics that offer respectable performance for all but the highest end production with prices in the $150-$350 range. These are sold by such companies as Audio Technica, MXL, Rode and many others.
Be aware that all capacitor mics have some electronics located near the capsule. Solid state models can be powered by so-called “phantom power” which simply sends DC electricity up the same cable that carries the resulting audio signal. Most all audio computer interfaces, modern mixers and standalone recorders can provide this.
Some capacitor mics use a small tube, rather than transistors, in the head electronics and they are sold with a separate power supply. Some people feel the tube electronics produces a warmer sound, especially on loud passages. Tubes don’t travel as well as solid state gear so I tend to stick with solid state, but many people are tube mic enthusiasts. Those models usually cost a bit more than the solid state versions.
Capacitor mics used for voice recording usually have large diaphragms (about 1 inch) and are located so that one talks into it on the side. These are called “side address” mics and are very common. There are capacitor mics with the diaphragms in front (see the images of the dynamic mics above). Some of these “front address” mics have small diaphragms and are more intended for micing instruments. But they can be used for voice as well.
Is there a middle ground between the low end, mostly Chinese or Russian made, mics and the high end models like the Neumann U87 that cost over $3000? The answer is yes. One popular solution is the AKG C414 mic which sells for just under $1000. Also, some companies, especially Michael Joly Engineering, take cheaper Chinese and Russian mics and modify them by substituting low cost electronic components (put in to keep the price low) with higher quality parts and sometimes even by modifying the headbasket (or shape of the mic). The Michael Joly Engineering mics compare favorably with very high end mics and, with the cost of the mic plus modification, will cost only a few hundred dollars For example he sells near clones (in sound) of the Neumann U87, by modifying Rode and MXL mics. He even has a side-by-side sound comparison between the U87 and his modified mics on his website: http://www.oktavamod.com/. I own five mics he has modified and am happy with the results.
For most people getting into voice production, the capacitor mic will usually be the most satisfactory choice. But not always.
The Ribbon Transducer (also sometimes called a “Velocity Mic”)
The ribbon transducer used to be extremely common in radio and recording studios in the 1940s, 1950s, and 1960s. Then its popularity faded as the capacitor mic took over. But in the mid 1990s this transducer was re-discovered and now there are dozens of ribbon mics being made in prices ranging from under $200 to about $8000.
The reason many people like the ribbon sound is it tends to be warm. In music it can keep a piano from sounding tinny or a violin screechy. For voice it can smooth out highs, especially in female voices. Because of the way it is built (see the following section on polar patterns) it has lots of “proximity effect.” That means when one talks fairly close to the mic the low frequencies are enhanced. Perfect for a voice like my own which tends to be thin and nasal.
BUT, it comes with some serious negatives:
Most ribbon mics are EXTREMELY fragile. Don’t ever blow into one to see if it is on. That will ruin the ribbon. (Ribbons can be replaced but it is a delicate and often expensive proposition.) They are not suited for use outdoors and don’t travel all that well because they are so fragile. Not a mic you would just throw into a road case with some cables. When traveling with a ribbon a very padded container is to be desired. Even dropping a ribbon mic can damage the ribbon.
But fragility is not the only negative. The output signal is very low. That means one needs to feed the signal into a very high end microphone preamplifier or, as an alternative, use an in-line amplifier to boost the signal before going into a standard preamplifier.
This is kind of a specialist mic. I wouldn’t buy one as the only mic for your studio. I own three ribbon mics (really four since one is a stereo mic with two ribbon capsules set at an angle to each other). They are wonderful when you need them but the vast number of recordings I make, both voice and classical music, are done with capacitor mics.
Polar pattern just indicates the directions a mic is sensitive to relative to the front of the mic diaphragm. The most common pattern by far is the CARDIOID pattern which picks up sound from the front of the diaphragm but tends to reduce pickup of sounds from the sides, and especially the rear. Probably 80-90% of all mics sold for professional recording, voice or music, use this pattern.
The OMNIDIRECTIONAL pattern picks up sound from all around. It is good if you have a group of performers who need to be picked up on one mic. Also, this pattern tends to be free of proximity effect – the tendency of directional mics to emphasize bass frequencies when it is close to the sound source. Great for a male speaker who already has a deep voice that you don’t want to exaggerate.
The BI-DIRECTIONAL or FIGURE-OF-EIGHT pattern is the native pattern of virtually all ribbon mics. It picks up from the front and back, but less so from the sides. Great for interviewing someone with a single mono mic. It has the MOST proximity effect, so is good for beefing up a thin male voice.
The HYPER-CARDIOID mic is even more directional than a plain cardioid. These mics are usually long and thin front-address mics often known as “shotgun” mics because of their shape. Even though they are long and thin they are NOT the sonic equivalent to a zoom lens in photography. To get good voice pickup the person speaking should be able to reach out (or up or down) and touch the mic. Although these mics are mainly used on small booms for audio pickup for film and TV, some voice artists like them because they are not as “in your face” as mics that one be close to when speaking.
For good voice pickup with a cardioid dynamic mic, often the speaker should be 3-9 inches from the mic. We noted the “reach” of that transducer is not as great as other mics. For a cardioid capacitor mic (side address) the optimum distance might be 6-12 inches. (These distances vary by mic model and by the acoustic space being used.) But for a hyper-cardioid mic, usually a long front address mic with a small diaphragm, the optimum distance can be 12-30 inches. One model popular with voice artists who don’t want to work to close to the mic is the Sennheiser MKH 416 (pictured below). Other brands work well too. I personally use a Beyerdynamic shotgun mic which, despite the name of the company, is a capacitor mic of very high quality. But I mostly use it to record dialogue for films.
There are many accessories one can get for a good microphone, too many to discuss in any detail in this already-long post. But there are two that should be considered for voice recording.
A WINDSCREEN helps prevent pops from “plosives” in speech (“p” and “b” sounds) and also protects the mic from any spit a speaker might eject. These can be simply acoustically transparent foam coverings to more sophisticated discs and other protection. But very useful. I might discuss these more in a later post.
If a mic is on a floor or table stand that might pick up vibrations (such as from footsteps or machines that share the floor, then a SHOCK MOUNT is useful. It helps isolate a mic from stand vibrations. But more on these topics later.
Now go tell “Mike” you have found the perfect mic to record him!