iMac Audio issues...that damn annoying buzz

Discussion in 'iMac' started by RebelScum, Oct 23, 2007.

  1. RebelScum macrumors 6502

    Joined:
    Aug 15, 2007
    Location:
    Toronto
    #1
    Ther's probably a quick fix for this, but here goes:

    I have my iMac 2.8 wired to my home theatre stereo unit (some mid-range Sony receiver). Watching movies via Front Row is a bit frustrating, tho, because of the annoying audio. There is a loud buzzing sound coming from my speakers. I WAS having the same issues with iTunes, until I doscovered a preamp built into the iTunes equalizer, which I simply turned up...problem solved. Is there any kind of equalizer for either apps (like quicktime) or for the OS I can install? Any other suggestions on how to fix this?
     
  2. Sesshi macrumors G3

    Sesshi

    Joined:
    Jun 3, 2006
    Location:
    One Nation Under Gordon
    #2
    The built-in sound on all Macs (and most PC's) is still very mediocre. I believe most Macs have the worse of the current integrated sound chipsets - Realtek middle-of-the-road stuff. Hook it up to even a halfway crappy home audio system and you'll realise it's limitations.

    Have not bothered to find out what the iMac uses as I don't have Boot Camp on here. The best bet is a decent-quality external soundcard.
     
  3. RebelScum thread starter macrumors 6502

    Joined:
    Aug 15, 2007
    Location:
    Toronto
    #3
    Ya, the sound is very mediocre, which is a shame, because they have that great digital optical port.

    Here's something weird tho...whenever I boot into wXP, my sound leves are much higher, and when I boot bacnk into OSX, they drop right down again. It's almost like there's some kind of "limiter" in OSX that cripples the sound hardware. Is it just me? Both volume levels are the same.
     
  4. psonice macrumors 6502a

    Joined:
    Jul 22, 2005
    #4
    If you can use the digital out rather than the analogue, it should be perfectly clear. Having said that, I've used the analogue out with a pair of high-end sennheiser headphones, and noticed no buzzing noise (I've found all the macs I've used so far WAY better than the average PC for clean audio out btw). It's worth checking your cable, and making sure that it's not too close to mains cables etc.
     
  5. RebelScum thread starter macrumors 6502

    Joined:
    Aug 15, 2007
    Location:
    Toronto
    #5
    Using digital, and just replaced cables. I'm gunna try an external USB card and see how that works.
     
  6. ruffles macrumors newbie

    Joined:
    Mar 9, 2008
    #6
    Video Crosstalk

    Hi guys,

    I thought I should reply to this thread as I have experienced the same issue. First thing i suggest trying is unpluging the video cable from the mac. If the buzzing stops then the audio and video cables are two close together or are of bad quality. Composite video signals often cause problems with audio signals because of the high frequency. This can happen with any PC/Device.

    Hope this works,

    Russell
     
  7. Killyp macrumors 68040

    Killyp

    Joined:
    Jun 14, 2006
    #7
    There should be no buzz if you're using a digital connection. If there is, then the issue is with your amplifier, not the iMac.

    I'd avoid the iTunes equalizer, turn it off completely. Just turning up the preamp is going to make it distort terribly (like turning an amplifier up way too loud).

    If you use the optical output from your iMac, and run this into your Sony receiver, there should be no buzz at all.
     
  8. SaSaSushi macrumors 68040

    SaSaSushi

    Joined:
    Aug 8, 2007
    Location:
    Takamatsu, Japan
    #8
    I've been using the optical cable to a Sony home theater system on both my current 24" alu iMac and the 20" Core Duo iMac that preceded it. I've never had any problem with distortion. I definitely agree distortion, if you have it, is a problem on the amp end. With S/PDIF out its nothing but digital data passing through that cable which your amp then decodes. Signal distortion is a non-issue.

    I also don't think the Realtek chipset is bad at all. ;)
     
  9. Rickeo macrumors newbie

    Joined:
    Mar 4, 2008
    #9
    You are going to want to avoid you're iMacs internal DAC like the plague. Run optical out to you're AVR. If you're iMac uses the SigmaTel Digital card like mine does, its D to A conversion is awful. And as mentioned above, turn off the preamp/EQ in iTunes, aswell as the Sound Enhancer. They accomplish nothing except making you're music sound horrible.
     

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