Audio line in isn't mic in...right?

Discussion in 'Mac Pro' started by AlmightyG5, Jan 27, 2006.

  1. AlmightyG5 macrumors 6502

    Joined:
    Jul 7, 2005
    #1
    I have one of those headphone/mic combo unit. It has two plugs...one for the phones and one for the mic. I tried plugging the mic-in into the audio-input on my iMac and it's doesn't respond in the sound preferences. Is it suppose to? or you don't use line-in for mics? If not, my mac has nothing for my mic?
     
  2. macmanmatty macrumors regular

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    Jul 10, 2005
    Location:
    I have calculated my velocity so precisely that a
    #2
    It should work my line can respond to any sound coming through it mics, cd players, cassette players, even head phones can work as a very bad mic through my line in on my pmac. It should work on yours
     
  3. howesey macrumors 6502a

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    Dec 3, 2005
    #3
    The input is line level, you'll need a preamp to get the mic level to line level.
     
  4. lbodnar macrumors regular

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    Jan 5, 2004
    Location:
    UK
    #4
    It's not only about levels. These tiny mics that are everywhere now - are electret technology capsules that have one tiny amplification stage inside them and need a power supplied to them on the same wire as they send signal back. Just a few volts will do (e.g. 2xAA batteries.) Audio signal then gets separated from this DC power in a recording device - just one cap will do :)

    So even if you crank up the amplification levels they will still be dead without that power supply.

    Obviously, microphone preamplifier will have this phantom power if it was designed to work with these microphones (I guess they all now are.)

    Alternatively, big good old electrodynamic microphones with moving coil inside can be used, however their output is still low and they need frequency compensation for decent use anyway (not enough lows.)

    Boring? Yes I am!
     
  5. Mac_Freak macrumors 6502a

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    Apr 22, 2005
    #5
    Try opening an app in your utilities folder called Audio MIDI Setup and there under the "Audio Devices" tab, change the Audio Input to "Line In"
     
  6. wangahrah macrumors newbie

    Joined:
    Feb 22, 2001
    #6
    I don't know about the G5 imacs, but I ended up buying an iMic which you can plug the mic in/line out too and then it runs through USB. Works perfectly on my powermac G4 with the unpowered line in.
     
  7. guitar-picker macrumors newbie

    guitar-picker

    Joined:
    Jan 29, 2006
    Location:
    Syracuse NY
    #7
    What does 'line level' mean?

    Wish someone could define what "Line Level" means. I've got a pre-amp between my guitar and the Line In plug on my Powerbook, but even with the pre-amp turned to max volume, the guitar volume at Max, and the input level turned all the way up in the powerbook sound control panel, the audio signal from my guitar barely registers on the Mac.

    Also, when I record guitar, and plug headphones into the Powerbook Headphone jack, I can't hear my guitar. I'm wondering if the Powerbook is only capable of either sound input via the Sound In jack, OR sound output via the headphone jack, but not both simultaneously...
    :confused:
     
  8. frankblundt macrumors 65816

    frankblundt

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    Sep 19, 2005
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    South of the border
    #8
    i think you need to be running a recording app with a monitor setting to be able to hear back what you're putting in (incidentally, using iMic and SpinDoctor i can't monitor and record simultaneously either without it garbling, but i think this probably has more to do with the USB bus on my g3 getting overwhelmed).
    I had similar problems with signal level at line-level - ie the line-out signal from the back of an amp - into the mic jack, trying both the tape and vcr line out. I ended up getting the iMic which has a switch for line-level (amplified) or direct input (guitar/mic) and delivers a much better signal level for both. It may be your pre-amp is just lifting the signal to direct input levels and needs a further kick (from an amp or another pre-amp like iMic) to lift it to the line-level the mac sound input expects.
     
  9. DrNeroCF macrumors 6502

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    Sep 2, 2004
    #9
    It'll be really low. I use my video camera and a bunch of cables to get my mic up to level on my Powerbook... pretty pathetic... ya...
     
  10. mikemodena macrumors 6502a

    mikemodena

    Joined:
    May 30, 2005
    Location:
    Connecticut
    #10
    I went to CompUSA today looking for an iMic, but with it being CompUSA, they had 3 in stock.. but couldn't find them in the store. I just ended up buying a Logitech USB headset to use with Skype.
     
  11. kiwi-in-uk macrumors 6502a

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    Sep 22, 2004
    Location:
    AU
    #11
    All these posts are interesting, but leave me a bit confused. I want to get a combo headphone/mic so I can do some product support using Skype.

    Are all combo headsets ok to use through the PB audio ports? Or would I need something like iMic? Or would I have to use a USB headset?
     
  12. frankblundt macrumors 65816

    frankblundt

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  13. kiwi-in-uk macrumors 6502a

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    Sep 22, 2004
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    AU
    #13
    Ah - that's great - thanks. Bluetooth sounds the ticket.
     
  14. howesey macrumors 6502a

    Joined:
    Dec 3, 2005
    #14
    Ok, ok, a preamp that has phantom power would be useful. Just remember, to use 48v phantom power, you need to use a balanced connection.

    guitar-picker, you may also need a direct injection box with your guitar, or if your amp has a DI out, use that to go into the preamp. DI boxes do several things - they match impedence, provide a ground and also balanced connections.

    Line level and mic level. Line level has a level of +4dBu (IIRC 1.228VRMS), whereas a mic has levels of around -60 to -70dBu (different between mics). To say 3dB is an increase of 2x the power, I'm sure you can see the difference in levels.
     

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