Microphones Product Guide
So, are you a DJ? No? Then maybe an amateur singer, a teacher, a reporter, a teenager with an upcoming talent show or even a wedding singer? All these people and more use microphones to get their message out to large crowds, television audiences or personal purposes. Because of the limitations the human voice has with loudness, and the boundaries air has in directing sound, microphones were created. A microphone's primary purpose is to pick up sounds that are fed into it from a certain direction, depending on which microphone you're using. People use microphones on many occasions like parties, conferences, weddings, school, talent shows, outdoor events, and musical performances. Learn the basics in the differences in microphones and shop for all types of microphones right here at JR.com from manufacturers like Sennheiser, Audio Technica, Sony, Motorola, Koss and more. Humans talk "into" microphones ('mics' for short). A microphone takes the air pressure coming from our voices, and changes that into patterns of electric current. This electric current is then amplified and sent to a loudspeaker or headphone. There are large mics and little tiny mics that clip onto clothing. There are mics that pick up sound best when you're directly in front of it, and others that work best collecting sound waves from all over a room. There are corded and there are wireless microphones. Basically, there's a microphones for everyone out there!
Most handheld microphones come with an on/off switch and can work with either an AC adapter or batteries. Some even come with a number of accessories like clips, cases, shock mounts, adapters and cables too.
Microphones connect to all sorts of devices too, and their output can be heard in a number of various places. Normally microphones connect to some kind of amplifier or sound stabilizer with equalizers. They can also be directly connected to camcorders and tape recorders and even minisystems for karaoke.
Types of Microphones
Microphones may be used basically anywhere. However, many microphones work better in certain environments than others. When it comes to the differences in microphones, you have to keep two things in mind. In terms of how they are made: whether you're getting a "dynamic" or "condenser" microphone, and how they pick-up sound.
Dynamic vs. Condenser
The terms "dynamic" and "condenser", refer to the actual make-up of each microphone. Each is engineered a little differently than the other. Dynamic microphones are known to be more ruggedly designed and use magnetics. Condenser microphones are known to be smaller and more sensitive than dynamic microphones and are powered by electricity. Handheld microphones are usually dynamic, and small lavaliere mics (the ones that are small enough to clip onto clothing) are condenser mics. The microphones found in most camcorders and tape recorders are all condenser mics too.
Most microphones are labeled and named according to the way they pick up sound or to their "pick-up patterns". There are omnidirectional, unidirectional, cardiod, supercardiod, and shotgun pick-up arrangements. Here are the differences and ideal environments and uses for each.
Directional microphones are designed pick up sound from the front of the device, and rejects any sounds that comes from any other direction. Bi-directional microphones (which are also a type of "directional" microphone) pick up sounds from both directly in front of and behind where the microphone is situated. Noise that comes in from the sides of the microphones is immediately canceled by the internal circuitry of the device. These types of microphones are best for speakers, singers and interviewers.
Cardioids are a type of directional microphone. Their name refers to their pick-up pattern, which is a mushroom type pattern directly in front of the device. This pattern is popular for sound reinforcement or recording concerts where audience noise is a possible problem. Sounds from the back are not completely rejected, but are reduced to about 10-30 dB. Hyper Cardioids and Super Cardioids all follow the same pattern with a slight variation on the width and length of the shape of the mushroom pattern. Shotgun microphones, which are usually used with a long stick and pick up sounds at a greater length directly in front of and slightly behind the mic, are also a form of directional microphones.
These types of microphones are the simplest in design, style, and function. Omnidirectional microphones pick up sound from just about every direction equally. Most of the microphones built into camcorders and tape recorders are omnidirectional. They'll work about as well pointed away from the subject as pointed toward it. This type of microphone may work best in places where you need a group recording, perhaps a classroom where you want every sound to be recorded.
Lavalieres are the smallest type of microphone available today. When they were first made, lavalieres were microphones hung around a person's neck or body. Now lavaliere microphones have gotten even smaller and are made to clip on ties and blouses or on anything.
Lavaliere microphones leave the talker's hands free to gesture, hold notes, or demonstrate something. Because of their small size, they tend to disappear on camera and people wearing them tend to forget they are on. Using a lavaliere helps to also keep the distance from the microphone to the talker's mouth fairly constant, lessening the need for mixer adjustment once levels have been set.
Another form of hands-free microphone is the headset microphone. Although they cannot truly be categorized as Lavalieres, they are used to make the speaker or singer talk (or sing) into a microphone without having to hold the device. Many modern day young singers use this form of microphone when on stage in concerts.
There are three types of wireless microphones available: handheld, lavaliere, and headset microphones. Wireless microphones have two major components: the microphone and the transmitter, both of which are battery powered. The transmitter is small enough to fit into the microphone handle in handheld units, or into a small pocket-sized case for clip-on microphones. Since the microphone and transmitter are battery powered, the user is free to move around. A receiver that is wired to a speaker picks up the audio that is transmitted.
Lavaliere mics are wired to miniature body-pack transmitters, which fit into a pocket or clip onto a belt. You can normally travel about a hundred feet (sometimes more with professional microphones) away from a transmitter and still be able to talk into a wireless microphone and be heard clearly. Wireless headset microphones are fairly new. They strap around the head and allow for the same freedom and performance as lavalieres. Many modern day music artists wear these while performing in concerts. Because of their dance movements a headset in this case works better than a wireless lavaliere or handset microphone.
No two mics are exactly the same, and a main determining factor of how well a device receives and transmits sound is its frequency response. The frequency response of a microphone is a measure of the consistency with which it converts incoming sounds into electric signals to be transmitted. A good microphone would have a consistent frequency response level no matter what it picked up or from where.
The human voice is generally incapable of producing frequencies below 100Hz. However, if microphones will be used in musical performances, many instruments have the ability to play at very high and extremely low frequencies. These unique sounds will only be picked up with a microphone with a frequency response that at least covers the human hearing spectrum, which is from 20-20,000Hz.
Some microphones have varying frequency response rates depending on how a sound enters the device, which is not always bad. However, this may help to produce feedback (see "feedback" section below).
A microphone's sensitivity is determined by how well it can pick up even the quietest of sounds. It is a measure of how much electrical output is produced by a given sound. If a faint beep is sounded in front of two microphones and one puts out a stronger signal (higher voltage), that microphone is said to have higher sensitivity. However, a microphone with high sensitivity doesn't mean the microphone is "better" than another with a low sensitivity. Sensitivity is measured in decibels or (dB). The higher the dB rating, the more sensitive the microphone.
Impedance and Ohms
There's a rating called Ohms and it relates to the resistance (impedance) of signal flow from your microphone to your receiver or amplifier. For microphones, low impedance is less than 600 ohms, medium impedance is 600-10,000 ohms, and high impedance is greater than 10,000 ohms. The impedance factor has nothing to do with sound quality but has something to do with the work that the speaker and receiver must do together to deliver sound. A receiver rated at the same ohms range as a microphone is the best match. If you use microphone with an Ohm rating lower than your amplifier is rated for, it is possible that there may be some signal loss.
The most basic microphones have a either a 1/4" phone plug or a 3.5mm mini plug. Many higher end model microphones come with an optional XLR connector, one that is use with much professional DJ equipment. Most mics connect to devices like mixers, amplifiers, and cassette decks via a 1/4" phone plug. Lavalieres tend to connect either through a 3.5mm mini plug or an XLR connection. Hooking up the microphone also depends on what connection your input device has available. Many adapters are available turning 3.5mm mini plugs into 1/4" phone plugs and vice versa.
Microphones never work alone, in fact, there are many accessories that are sometimes necessary when using microphones. Mixers are usually desired to alter sound levels when needed. There are also smaller accessories like windscreens to eliminate popping noises, shock mounts to help reduce noise transferred to a mic through its mounting hardware, microphone stands, power supplies and more.
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