Frequency Response, Impedance, Sensitivity

Discussion in 'General Electronics Chat' started by Lightfire, Dec 15, 2011.

  1. Lightfire

    Thread Starter Well-Known Member

    Oct 5, 2010

    I want to know what are

    • Frequency Response
    • Impedance
    • Sensitivity
    These are the microphones that I wish to buy but having difficulties choosing but these are all affordable.:cool:

    Candidate Number One

    • Frequency Response: 30~15,000Hz
    • 2.2k Ohms
    • Sensitivity: -52dB 5dB (at 1kHz, 0.28V)
    Candidate Number Two

    • 50-13000Hz
    • 600 Ohms
    • -58dB ± 4dB at 1KHz

    Candidate Number Three

    • 80-12000Hz
    • 600 ohms
    • -58dB ± 4dB at 1KHz

    Candidate Number Four

    • 20-2000Hz
    • 600 ohms
    • -58dB ± 4dB at 1KHz

    I also want to know what does these signs means

    • Φ I found it in Plug section of microphone's specifications (Φ3.5mm stereo plug)
    • ±

    Thank you.

  2. Wendy


    Mar 24, 2008
    Frequency Response - The range that can be heard, if not by humans, then by electronics.

    Impedance - The conductivity of a microphone. Generally you need the device being fed from the mic the same as the mic impedance for best power transfer, but it is not necessary.

    Sensitivity - the quietest sound the mic will still pick up.

    Plus/Minus - also +/- . Use by many power supplies, two batteries with the ground between them are a plus and minus power supply.
  3. tommydyhr

    Active Member

    Feb 3, 2009
    And the Φ corresponds to the diameter.

    In this case it would be the diameter of the stereo-plug.
  4. Wendy


    Mar 24, 2008
    That I didn't know.
  5. tommydyhr

    Active Member

    Feb 3, 2009
    It's worth noting that the Φ (greek capital Phi) isn't how you'd usually represent diamater. A much more common letter for representing a diameter would be "ø" - not as in the scandinavian letter, but as a "circle with a stroke"-symbol.

    Capital Phi, when working with electronics, usually symbolizes phase angle or work function.
  6. Audioguru

    New Member

    Dec 20, 2007
    The frequency response ratings are absolutely useless because it does not say how much the response varies (plus and minus 3dB or less is very good) but these mics might vary plus and minus 20dB or more.

    A half-decent mic has a datasheet with a frequency response curve. I attach the response curve of a Shure SM-57 dynamic mic with a rated frequency response of 40hz to 15kHz but the graph shows that it is plus and minus 3dB from 120Hz to 5kHz.

    I also attach the response curve of an electret mic with an excellent flat frequency response.