I think my Macbook's Input port is broken

Discussion in 'MacBook Pro' started by Enigmur, Nov 6, 2007.

  1. Enigmur macrumors newbie

    Oct 25, 2007
    When using Garageband, if I select the direct audio input, i get a fuzz - even when the instrument isn't connected. If I use amp modeling with any sort of gain, it really fuzzes.

    Here is a link to an mp3 i exported from Garageband - it is just a recording of the sound created if the input is switched to the built in input - no guitar attached, with amp simulation on.


    I have been recording with my guitar straight into the Mac.

    The noise is always there, even if i record my guitar clean then change the amp simulation, it amplifies the fuzz sound.

    If there is no way to fix this, I'll have to send it back for repair as it is absolutely vital i have audio input.

    Any ideas?
  2. Enigmur thread starter macrumors newbie

    Oct 25, 2007
    Doesn’t anyone have any ideas?

    If I got the buzz only when the guitar was plugged in, I wouldn’t be worried. It’s the fact that it’s picking up buzz and hum with nothing in the port.

    I might have to ring Apple about it.
  3. sycho macrumors 6502a


    Oct 7, 2006
  4. amusiccale macrumors 6502

    Jun 5, 2007
    as a long time recorder of music on sub-standard equipment--you will want to make sure your input levels are matched--balanced and unbalanced, high and low impedance. Plugging a guitar straight into a 1/8" port is a bootleg operation at best: pick up(borrow?) a cheap behringer mixer and run the headphone or line level out (please remember LINE LEVEL if it's a powered mixer--do not run the full wattage into your mac) from there into the computer and see what happens. Also, check the guitar on a good amp. If it's single coil, there can be a constant buzz. If the circuit that you're plugged into isn't grounded correctly, that could also cause a buzz. You may also have a ground loop.
  5. Enigmur thread starter macrumors newbie

    Oct 25, 2007
    I realise using Line-In is bollocks, but I’m trying to figure out whether or not it is broken – or if it just sucks and when gain is applied in garageband it picks up god knows what.

    I’m going to be using Protools next year and will purchase the m-Box with it.

    It still buzzes and hums when the recording volume is turned right down, so I don’t think its because I have some level turned up too high – though it sounds like it gets a bit of feed back, and the hum is like when you have a guitar way too close to an amp.

    Can you get some sort of cheap adapter which converts an instrument cable to USB? Or do they all contain some kind of preamp and cost a bit.
  6. Enigmur thread starter macrumors newbie

    Oct 25, 2007
    Cheers for the reply,

    I’m aware that a guitar will introduce buzz and interference – but my main concern is that I’m picking up the buzz without anything plugged into the Line-In.
    If I set Garageband to record from the Line-In, then turn the recording level up – I can faintly hear the sound. If I turn on amp modelling and select anything with gain, it is really loud.

    The sound is still there at the same volume if I plug the guitar into the mac – you can still hear the guitar in the recording fine, it sounds fine – but there is that horrible buzz in the background.
    I noticed it the first time I tried recording and figured I may have had a setting wrong, or my guitar was just being noisey – but seeing as it does it without anything connected, I figure it must be the port that is the problem.

    I have always recorded with a guitar straight into the Line in – or guitar to an effects processor, then into Line-In.

    I bet if I did use a mixer or anything into it – the sound would still be there because it HAS to be coming from the Line-In port. I’ll try a few more things tonight, like running the sound output to my stereo instead of the Mac speakers, and I’ll try playing around with recording at really low levels then raising them on the track after its recorded.
    But at this stage it certainly seems like it’s a fault on the audio controller or the port itself.

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