Microphone converts the sound wave from the sound source into an electrical signal impedance
is the ac resistance of these audio electrical signal voltages and it is measured in ohms
there are two main impedances namely output impedance and input impedance output impedance
is determined by the microphone and the input impedance is determined by the inline audio
device such as a pre-amp camera phone tablet etc. in order for the electrical signal from
microphone to properly travel the microphone's output impedance must bridge the input impedance
of the pre-amp device input impedance is also called load impedance all the electronic devices
that generate an ac voltage have an output impedance the output impedance should be at
least four times higher than the input impedance microphone output impedance is not a constant
value and it changes with the frequency however for simplicity it is denoted by a single value
which is its nominal output impedance value output impedance is classified as follows
low impedance mics less than 600 ohms medium impedance mics 600 ohms to 10,000 ohms high
impedance mics are greater than 10,000 ohms the higher the impedance the cheaper it is
to manufacture the microphone high impedance microphones should not be used with a long
run audio cables the output impedance creates a low pass filter in the cable the longer
the cable the worse the audio quality you will get for a high output impedance microphone
consumer karaoke microphone is a good example of a high impedance microphone some cameras
support an output impedance of up to 600 ohms so it is very important to check the input
impedance of the inline device if you have got a medium to high output impedance the
audio quality of the microphone is related to the pre-amp input voltage the relationship
between the microphone output voltage pre-amp input voltage input impedance and output impedance
is as follows voltage at the pre-amp input is equals to input impedance of preamp times
voltage at the microphone output divided by the sum of input impedance of preamp and microphone
output impedance to better understand output impedance let's enter some actual values into
the impedance voltage equation comical track shot shotgun microphone has got an output
impedance of 600 ohms canon cameras have got an input impedance of 2200 ohms for a condenser
mic now let's apply a very low microphone output voltage of just one milli volts this
gives us a pre amp input of just 0.8 millivolts the ream voltage can never be higher than
mike's output voltage the lower the output impedance the closer the rear amp voltage
is to the output voltage therefore to achieve as high as possible re-amp voltage we need
as low as possible output impedance from the microphone I hope this video helped you to
better understand the output impedance if you have any questions please let me know
in the comments to learn more about microphones please watch my other videos to my site and
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