How to Buy Microphones on eBay

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How to Buy Microphones on eBay

Purchasing microphones on eBay is an easy and convenient, the ideal way to comparison shop for myriad makes and models from the comfort of one’s own computer. Before shopping for microphones on eBay, it may prove helpful to understand a little bit about microphones, as well as what types of features to look for that suit the user.

Essentially, a microphone converts audio signals into electrical signals. First patented by Thomas Edison in 1877, he designed and built a carbon microphone that worked by passing a voltage between two conducting plates. Between these plates were fine carbon granules, and the rear of these plates was fixed, while the front was left open to the sound. The sound waves caused the carbon granules to move slightly, thereby altering the resistance between the plates. This difference in resistance was then amplified by the voltage applied across them.

Though these early carbon microphones were relatively low quality, they were very robust, and produced a sufficiently high output to readily be used by early valve amplifiers nearly fifty years later, in the early 1920s. Believe it or not, these were still in use in many telephone systems right up until the 1980s.

Since then, the design has largely been surpassed by newer, higher fidelity types, and it is these types that purchasers should learn more about. Whether the user is looking for a microphone suitable for fun nights with karaoke, or one for, say, more private chats with a loved one via the Internet, it easy it is to buy a microphone that delivers on eBay.

Microphone Types

There are many different kinds of microphones, employing many different ways to convert sounds into electricity. Each different microphone type typically has a specific use, and while the information provided here is not exhaustive, it should help point any buyer in the right direction.

Condenser Microphones

The condenser microphone has been around for many years, and is generally considered to be very high quality; many of the well-known brands produce top quality models that offer a superior output, suitable for the exacting demands of a modern recording or broadcast studio. In operation, sound waves act like a diaphragm, moving it minimally. This movement varies its capacitance slightly, and is then converted into an electronic signal by a pre-amplifier. The word ‘condenser’ is actually the old-fashioned word for a capacitor.

Whereas cheaper microphones of different constructions will have frequencies where they are much louder and others where they are much quieter, condenser microphones give an output signal that is essentially consistent despite frequencies. This eliminates the booming bass and scratchy high frequencies associated with inferior quality microphones. In fact, many professional sound engineers specifically use condenser microphones for singers’ vocals, as they produce a clean and clear signal within the human vocal range.

On a practical note, most condenser microphones need an additional power supply battery of roughly nine volts. This is often incorporated as a small battery within the microphone casing or, alternatively, a small inline box situated along the length of the output wire.

Electret Condenser Microphone

A variation of the condenser microphone is the electret microphone, invented by Bell Laboratories in 1964. This works similarly to a condenser microphone, but without the need for an external battery. Instead, the two capacitive plates are ‘pre-polarised’ in much the same way as a magnet is magnetised before use.

Electret microphones do not suffer from electrical interference in the way that dynamic microphones can and, because they are so cheap to produce and have a relatively good frequency response, electrets have found their way into myriad uses, from computer headsets to cell phones to PDAs.

Crystal Microphones

Crystal or ‘piezo-electric’ microphones work on the ‘piezoelectric’ principle. When certain materials are subject to pressure, they produce a voltage. Crystal microphones were commonly sold with valve home recording equipment in the 1950s and ’60s because their high output impedance matched the high input impedance of valve pre-amplifiers well. Because of this high impedance, they suffer from poor noise figures, both from the microphone itself and its connecting leads. These days, they are mainly used in electronic drum kits to trigger sound samples, or in situations where the recording of sound may be difficult, such as underwater under extreme pressure.

Dynamic Microphones

These are far and away the most popular type of microphones in use today by karaoke artists and pub singers. While not producing quite as high quality output as a condenser microphone, the dynamic microphone is used the world over as the microphone of choice. Many of the larger, high-end manufacturers that supply the professional market also make dynamic versions suitable for pub and small venue use.

A dynamic microphone works in exactly the opposite way to a loudspeaker. Instead of passing current through a coil in a magnetic field, thereby moving a diaphragm attached to the coil, a dynamic microphone works by the movement of a diaphragm due to sound waves. This diaphragm is physically connected to a coil which is itself in a magnetic field. Because the coil is moving in a magnetic field, an electrical signal appears across the coil. This is called magnetic induction.

With recent advances in coil, diaphragm, and magnet technology, modern moving-coil, dynamic microphones are extremely robust, and are often used on stage by artists and performers around the world.

Ribbon Microphones

Ribbon microphones work in essentially the same way as a dynamic microphone, in that a ribbon or corrugated, conducting material is held in a magnetic field. When the ribbon vibrates due to sound, as small voltage is produced in the ribbon. It is this voltage that is then amplified to produce the electrical signals. Ribbon microphones are generally used by recording studios as they produce a very high quality output. In the 1930s, ’40s, and ’50s, ribbon microphones were commonly used by radio stations. They are generally rectangular in construction and are easily recognisable.

Classically, ribbon microphones, by their very construction and design, were very fragile, and suffered from the effects of vibration, particularly from the wind when used outdoors, however, recent advances in technology and their construction means that modern ribbon microphones are no longer classed as purely recording or broadcast studio microphones.

Microphone Type

Use

Condenser

High-end studio, professional

Electret Condenser

Mass market, ubiquitous

Crystal

Generally archaic, except in drum machines

Dynamic

Karaoke and pub / club singers; most popular

Ribbon

Ultimate high-end studio

Microphone Output Plugs

Microphones feature a variety of different plugs, each one suited to a particular type of use of the microphone.

Balanced or unbalanced

High-end microphones tend to run as ‘balanced’. This requires there be two signal wires surrounded by a single earthed sheath that cuts down unwanted hum and other noise. Most mixing desks have ‘balanced input’ sockets to allow for this. When running a balanced microphone system, the lead running between the microphone body and the mixing desk will be a 3-pin XLR-type lead. The female end will plug into the body of the microphone itself, while the male end will plug into the desk.

Lower cost microphones tend to be unbalanced, and their hum and noise pickup are higher than balanced microphones. In an unbalanced microphone lead, a 3-pin XLR socket manually clicks into the male socket in the body of the microphone, while the other end normally terminates in a 1/4-inch mono jack plug that plugs into the amplifier or other piece of sound equipment.

With the increasing popularity of highly portable recording equipment, and of course, the now common use of microphones with computers and PDAs, many microphones now come with a standard 3.5 mm plug.

Buying a Microphone on eBay

Buying a microphone on eBay can be simple and fun. Whether you fancy yourself a karaoke crooner, a pub singer extraordinaire, or you simply want to chat more easily with friends and relatives via the Internet, there are thousands of microphones to choose from on eBay.

If you’re looking for a microphone to plug into your computer, or a microphone for your laptop or PDA, be sure to check the kind of plug fitted to the microphone you are interested in. Some microphones are supplied with an adapter, and their advert will say this. If the microphone you choose has the wrong type of plug on the end, then there are many adapters available to choose from on eBay.

If you’re looking for a karaoke or other public performance-type microphone, there are many wireless microphones now available at very reasonable prices. Of course, having a wireless system means that you may roam amongst your adoring fans without worrying about lengths of wire trailing behind you. It also means that come the end of the night, you’re not having to coil up hundreds of meters of tangled, often drink – soaked cabling.

Conclusion

Choosing the right microphone from the hundreds, if not thousands, on offer may seem daunting at first, but with careful use of eBay’s filtering system, the purchaser can very easily find the perfect microphone for the job.

Whether the user wants a high-end condenser microphone for possible recording or broadcast studio purposes, or just a microphone for plugging into their computer to allow easy chatting to a friend or relative via the Internet, there are many choices available to suit every budget and style.

Knowing a microphone’s construction, its uses, and its limitations will help the user purchase the right microphone for the right situation. Once a microphone type has been chosen, the purchaser should then pay attention to whether the microphone is new or second-hand. Careful attention should also be paid as to the type of plug it terminates with, and choose an adapter as necessary.

From its humble beginnings in Edison’s laboratory over a century ago, the microphone has become ubiquitous in today’s computer-driven, always-connected society.

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