Microphones Part 3 - Impedance
In our final microphone blog for this season, we are going to look at MICROPHONE IMPEDANCE.
One of the most misunderstood areas of microphone selection is the microphone's impedance rating. In my experience and travels, I have learned that very few church media workers understand what imedance is or why an impedance rating is important. Today's lesson is intended to help you understand how it effect you and why it is important.
Impedance is an electronics term which measures the amount of opposition a device has to an AC current (such as an audio signal). Technically speaking, it is the combined effect of capacitance, inductance, and resistance on a signal.
Impedance is measured in ohms, shown with the Greek Omega symbol Ω or the letter Z. A microphone with the specification 600Ω has an impedance of 600 ohms.
All microphones have a specification referring to their impedance. I have usually found this somewhere on the mic itself, but you may have to look into your manual. If the microphone is WIRED, you can easily tell the difference because HIGH IMPEDANCE MICS have a 1/4" jack and mics with an XLR connector are LOW IMPEDANCE.
There are three general classifications for microphone impedance. Different manufacturers use slightly different guidelines but the classifications are roughly:
Low Impedance (less than 600Ω)
Medium Impedance (600Ω - 10,000Ω)
High Impedance (greater than 10,000Ω)
High impedance microphones are usually quite cheap. Their main disadvantage is that they do not perform well over long distance cables - after about 5 or 10 metres they begin producing poor quality audio (in particular a loss of high frequencies). In any case these mics are not a good choice for serious work. In fact, although not completely reliable, one of the clues to a microphone's overall quality is the impedance rating.
Low impedance is generally your preferred choice.
Remember, however, that a low impedance microphone should generally be connected to an input with the same or higher impedance on the sound board. If a microphone is connected to an input with lower impedance, there will be a loss of signal strength. There are converters, however, that can adjust your impedance level, HOWEVER, I really suggest purchasing a better quality mic than getting a cheap one and trying to convert it.
In some cases you can use a line matching transformer, which will convert a signal to a different impedance for matching to other components.
One of the most misunderstood areas of microphone selection is the microphone's impedance rating. In my experience and travels, I have learned that very few church media workers understand what imedance is or why an impedance rating is important. Today's lesson is intended to help you understand how it effect you and why it is important.
Impedance is an electronics term which measures the amount of opposition a device has to an AC current (such as an audio signal). Technically speaking, it is the combined effect of capacitance, inductance, and resistance on a signal.
Impedance is measured in ohms, shown with the Greek Omega symbol Ω or the letter Z. A microphone with the specification 600Ω has an impedance of 600 ohms.
All microphones have a specification referring to their impedance. I have usually found this somewhere on the mic itself, but you may have to look into your manual. If the microphone is WIRED, you can easily tell the difference because HIGH IMPEDANCE MICS have a 1/4" jack and mics with an XLR connector are LOW IMPEDANCE.
There are three general classifications for microphone impedance. Different manufacturers use slightly different guidelines but the classifications are roughly:
Low Impedance (less than 600Ω)
Medium Impedance (600Ω - 10,000Ω)
High Impedance (greater than 10,000Ω)
High impedance microphones are usually quite cheap. Their main disadvantage is that they do not perform well over long distance cables - after about 5 or 10 metres they begin producing poor quality audio (in particular a loss of high frequencies). In any case these mics are not a good choice for serious work. In fact, although not completely reliable, one of the clues to a microphone's overall quality is the impedance rating.
Low impedance is generally your preferred choice.
Remember, however, that a low impedance microphone should generally be connected to an input with the same or higher impedance on the sound board. If a microphone is connected to an input with lower impedance, there will be a loss of signal strength. There are converters, however, that can adjust your impedance level, HOWEVER, I really suggest purchasing a better quality mic than getting a cheap one and trying to convert it.
In some cases you can use a line matching transformer, which will convert a signal to a different impedance for matching to other components.
posted by onevoice at 6:47 AM
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