For anyone looking for a robust and reliable microphone of better-than-average quality, dynamic microphones, among the various types of microphone that are available, have always been a popular choice. This is especially true of musicians looking for a dependable microphone to use onstage.
About Dynamic Microphones
All microphones are transducers that convert sound vibrations to electrical signals of exactly the same pattern. Several different methods are employed that achieve the same end result. Dynamic microphones achieve it by having a moving coil that vibrates within a magnetic field in response to sound waves entering the microphone. Following the principle of electromagnetic induction, vibrations within the magnetic field induce a tiny electric current that varies in intensity exactly according to the vibration patterns of the coil. Unlike some other microphones types, dynamic microphones don't require any power source to function. The standard connection to other equipment is via the microphone's interference-shielded audio cable but USB Dynamic microphones are also available that connect directly to any USB port on a computer. Wireless dynamic microphones, which transmit their output by short-range radio signal to a waiting receiver, are also available.
Dynamic Microphone Quality
Among the various microphone types, condenser microphones are widely acknowledged to lead the field in terms of quality. Dynamic microphones aren't far behind, however, and there are many excellent-quality microphones used by amateurs and professionals alike. Condenser microphones may have the edge on quality, but dynamic microphones have other qualities that make them first choice for many musicians.
This is where dynamic microphones make their mark. They can withstand a lot of abuse, which makes them ideal for stage work. They are also resistant to moisture, which is an excellent characteristic, especially in outdoor situations. They are a popular choice of singers in rock bands, who know they can depend on them to perform well and survive the wildest excesses of a live rock and roll stage performance.
Most microphone manufacturers include specifications that show how well a particular model performs. Although presented in technical language, a basic understanding of the terms and diagrams can be useful in assessing a particular model's capabilities.
The frequency response of a microphone is a measure of how sensitive it is to sounds at various frequencies, from low-pitched bass tones to high-pitched treble tones. Unlike robustness and reliability, frequency response isn't a major selling point of dynamic microphones as other microphone types, such as condenser microphones, are ahead in that regard. Nevertheless, good-quality dynamic microphones have a frequency response that is easily good enough for live performance work. A good frequency response is one that extends to the far reaches of the audio spectrum, or at least the part of the audio spectrum that is audible. Human hearing extends from as low as 20 Hz (vibration cycles per second) to as high as 20,000 Hz. The best dynamic microphones can approach that, but as their frequency response graphs show, there is a sharp fall-off in sensitivity as it approaches those extremes. A flat-line graph of frequency response indicates an even response at all frequencies between the fall-off points. A graph that is uneven means that the microphone is more sensitive to a particular band of frequencies (bass mid-range or treble) than to others. That can be useful for selecting a microphone that's needed for a situation where, for example, it's being used to pick up sounds from an acoustic bass. A microphone with a pronounced sensitivity to low frequencies would be the best choice for that situation, and the frequency response graph shows clearly how suitable any particular model would be.
Dynamic Microphone Pick-up Patterns
Dynamic microphones, like many other types, can be designed to be more sensitive to sounds in certain directions relative to the position of the microphone. This may be shown on specification sheets as diagrams that indicate how sensitive the microphone is to sounds approaching in every direction. Pick-up patterns are commonly described as follows:
Sensitive to Sounds
|Circular||Equally sensitive to sounds in all directions|
Cardioid and Super-cardioid
|Most sensitive to sounds directly ahead|
|Bidirectional||Figure of 8||Most sensitive to sounds in front and behind|
Another factor that makes dynamic microphones the microphone of choice in live performance situations is their low feedback susceptibility. Feedback is a problem where the microphone's output signal, amplified and reproduced as sound from speakers in the normal way, re-enters the microphone only to be further amplified and output again and again. This 'runaway' cycle, called feedback, results in the familiar squealing sound often heard at live events and is a constant problem in live performance work. If the microphone's volume is is turned up too high, feedback occurs. Dynamic microphones have the edge over other microphone types in this regard. They can be used at higher volume levels without triggering the dreaded feedback cycle. Unidirectional dynamic microphones suitably positioned to be less sensitive to sounds from nearby loudspeakers, can avoid feedback problems even more effectively.
Buying a Used Dynamic Microphone
Robustness and dependability are among a dynamic microphone's major selling points, and this is even more true of used dynamic microphones. A used dynamic microphone, even one that has seen lots of action, is unlikely to suffer from any loss of quality. It may have long since lost its looks but, unless it has been physically damaged, it can be expected to deliver the same quality of sound as it did when it was new. The advantage, of course, is the price, which will be significantly lower than the retail price.
Where to Buy Dynamic Microphones
As a popular choice of microphone, dynamic microphones are available to buy from a variety of retail outlets. Apart from independent music and audio equipment shops, dynamic microphones can be found in the relevant audio sections of supermarkets and department stores. The greatest choice of dynamic microphones, both in quality and price, however, can be found online. From private sales of used dynamic microphones to the most recently-released models, there is no shortage of them.
How to Find Dynamic Microphones on eBay
Finding dynamic microphones on eBay is easy. Go to All Categories and then select Musical Instruments. By choosing a relevant category, such as Pro Audio Equipment and then applying filters, a user can see a list of dynamic microphones that suit their requirements. The filters, which are in the form of check-boxes located on the left-hand side of every listings page, can group the results in many convenient ways, such as by condition (new or used), available locally or within a specified distance, offered with free delivery, priced within a certain price range and much more. Given the sheer volume of dynamic microphones that are available on eBay at any time, they are an essential part of the search process for anyone looking for the best possible results.
While an on-page search for "dynamic microphones" will certainly return an impressively long list of dynamic microphones, searchers won't be quite so impressed by having to skip dozens of listings that are unsuitable for many reasons. That's why eBay provide categories and filtering options that enable any searcher to see listings that are relevant. For example, anyone looking for a used dynamic microphone probably doesn't want to see results containing brand new dynamic microphones that are out of their price league.
Dynamic microphones have been around a long time, which is testimony to the success of their 'moving coil' design. They have always been popular and are just as popular now as ever. New technologies are constantly emerging, some with better specifications, yet the dynamic microphone retains its reputation as a dependable and durable microphone of decent quality. Choosing the best model is simply a matter of selecting the one that is best suited to its intended use at an affordable price.