How to use a low impedance mic with Garageband?

Discussion in 'Digital Audio' started by Sequence, Oct 13, 2006.

  1. Sequence macrumors member

    Jun 11, 2006
    Hi everyone, I recently bought a new microphone (Sony F-V420) to do some Garageband recording, etc. When I plug it in my Macbook input port, the sound is very low, like if the microphone had no power or something. I've heard that because this is a pro level mic, it has a very low impedance. What would be the best way to fix this?
    1- Something like Griffin iMic? (Would it work?)
    2- A basic pre-amp
    3- ???

    I'm looking for something very cheap that won't reduce too much the quality of the mic signal...

  2. WildCowboy Administrator/Editor


    Staff Member

    Jan 20, 2005
    #2're going to need some sort of pre-amp to get your signal up. The iMic is a common choice.
  3. Sequence thread starter macrumors member

    Jun 11, 2006
    So, the iMic is kind of a preamp? I see no control on the thing... It output the signal to the required line-out impedance?
    Thanks for your reply.
  4. WildCowboy Administrator/Editor


    Staff Member

    Jan 20, 2005
    I'm no expert, and I haven't used an iMic, so you may get better answers from someone who's actually used it. But I assume the iMic automatically outputs at either line-level or mic-level using the selectable switch.
  5. CanadaRAM macrumors G5


    Oct 11, 2004
    On the Left Coast - Victoria BC Canada
    Introduction to Impedance

    Impedance is not the same as signal level The MacBook has a high impedence input, which is suitable for a low impedance microphone (the input impedence should be higher than the source impedance) BUT - the Mac requires signals at a higher voltage than the Sony mic is outputting.

    The Sony F-V240 is not what I would class as a pro, or semi-pro level microphone. It is a basic dynamic mic, it is a step up from entry level, however, it may suit what you need. It is a 600 ohm impedance mic, which puts it at the upper end of the "low impedance" range or the lower end of the "medium impedance" range.

    So a preamplifier is needed. The iMic may do the trick.

    If you want more flexibility and higher audio quality, and are willing to spend over $100, then consider getting a USB digital audio interface from Edirol, M-Audio, Alesis or many others, which will include one or more microphone preamps. Search on this forum for many threads and many recommendations. I lean toward one of the new USB or Firewire equipped analog mixers from Alesis and others (I think Phonic has one, Behringer does, but I don;t like Behringer much). These give you the ability to mix and control several microphones and line inputs, without having to continually unplug and replug, plus they are usable away from the computer as well for small gigs or analog recording.

  6. quigleybc macrumors 68030


    Jun 17, 2005
    Beautiful Vancouver British Columbia, Canada
    Good to see you spreading the knowledge again CanadaRam, haven't seen you round these parts lately.

  7. Sequence thread starter macrumors member

    Jun 11, 2006
    Thanks for your reply CanadaRAM, I just learned a lot reading your post.

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