Apogee Duet Basic Questions

Discussion in 'Digital Audio' started by iangriffiths, May 6, 2009.

  1. iangriffiths macrumors newbie

    Joined:
    May 6, 2009
    #1
    I've recently bought a Duet but i'm confused on a few matters.

    - The lights on the front frequently light up all the way until red when i play various songs in my iTunes, as if to indicated clipping. is this normal, are the tunes clipping or does the Duet just do that?

    -After the 'clipping' happens, the red lights remain on, even when music isnt being played - is this normal too?

    - Finally, when i start up my mac, the Duet makes a nasty clicking noise a few times...not sure if this is a dodgy one or i'm being paranoid? it's literally 48 hours from the shop.

    Any help would be much appreciated.
     
  2. Benguitar Guest

    Benguitar

    Joined:
    Jan 30, 2009
    #2

    Hi, I own a Duet as well.

    Yes, it is normal when you turn your computer on when the Duet is plugged in that you will get those "clicks". Mine does that as well, and I haven't had any problems with it, my guess is that clicking noise is just like the "chime" on a Macintosh for when it starts up.

    About the red lights and clipping, that drove me crazy for a while but then I tried calibrating my Apogee Maestro and I was able to lower the decibels and eliminate the clipping but still get the volume I wanted.

    Here is a screen shot of how I have my Duet set on my Apogee Maestro Mixer, basically turn down the decibels from the software to -4dB and leave the to hardware at 0dB.

    edit- I also lower the volume control within iTunes just so I don't risk blowing out my sound card in my Macintosh.
     

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  3. joe.cavers macrumors regular

    Joined:
    Sep 16, 2008
    #3
    I don't own a Duet, but I know its common advice to keep your iTunes volume around 75% or so if you're driving another device (in this case the Duet). Otherwise you overload the input, causing the clipping.

    JC

    P.S. That's only from memory, don't quote me on it, I could be wrong!
     
  4. iangriffiths thread starter macrumors newbie

    Joined:
    May 6, 2009
    #4
    Thanks for your help! That seems to have worked.
     
  5. joe.cavers macrumors regular

    Joined:
    Sep 16, 2008
    #5
    Awesome glad to have helped :) From what I remember the only volume you should ever max is the final one in the chain (i.e. the speakers). I have my Tannoy monitors maxed, but then have my Mbox volume variable and my itunes at about 75%, this seems to work for me!

    JC
     
  6. Luap macrumors 65816

    Luap

    Joined:
    Jul 5, 2004
    #6
    You see the clipping leds come on because the clip circuit leds on the Duet are extremely sensitive and will essentially show you intersample peaks/distortion caused by use of compressed music formats like MP3 or AAC etc..
    You can test this quite easily. Play a lossless or uncompressed music file. The clip leds likely will not come on at all. Now play the same track in a lossy format, like MP3 or whatever, and you'll get what you see now, the clip leds coming on a lot. Yet as far as audible levels are concerned, the 2 files appear absolutely identical.

    The distortion the clipping leds indicate in this case is nearly always inaudible (because the peaks are incredibly short in duration), so there isn't really much need to adjust levels in iTunes. Or even in Maestro. And if you do, you are unlikely to have to drop it by more than 1db or so. If you are that bothered by the clipping issue, then you'd want to not being using compressed music formats in the first place. Thats the ideal solution!
    And of course for more professional work, you'd never use compressed music file formats anyway.

    Outside of iTunes (like when recording) you'd want to be sure the red clipping leds never illuminate.

    While im here.. The clicking you hear from the Duet itself is nothing to be concerned about. Its the internal relays engaging/disengaging.
    Also, if I remember rightly, in the Maestro/Duet settings you can set how long the clip leds stay illuminated for after being triggered.
     
  7. MowingDevil macrumors 68000

    MowingDevil

    Joined:
    Jul 30, 2008
    Location:
    Vancouver, BC & Sydney, NSW
    #7
    Agreed, the start up clicking is 100% normal. If it doesn't click then you should be concerned.
     
  8. aznhobo macrumors newbie

    Joined:
    Aug 14, 2010
    #8
    so if i see the red lights come on, is it bad for any of my hardware? because i might just be lazy and let it run like that
     
  9. MowingDevil macrumors 68000

    MowingDevil

    Joined:
    Jul 30, 2008
    Location:
    Vancouver, BC & Sydney, NSW
    #9
    I don't think its necessarily bad for the hardware, it only means you've peaked or hit 0 db & above...with clipping you're bound to get digital distortion which is undesirable.
     
  10. Killyp macrumors 68040

    Killyp

    Joined:
    Jun 14, 2006
    #10
    Run iTunes at 100% - otherwise the iTunes volume control is interfering with the signal. When it's at 100%, it's not adding or subtracting anything from the signal. If the clip light comes on when playing music, then it means there's clipping on the recording.

    The sort of clipping you want to avoid is where the output of your iTunes is actually HIGHER than it should be (higher than 100% basically). Disable the iTunes EQ (any boosting in the iTunes EQ result in distortion/clipping, just like on an iPod/iPhone), and disable the 'Sound Enhancer' (which does just the opposite), and keep the sound check off. Then iTunes will be passing the waveform straight through CoreAudio into the interface.

    The pops & crackles you're hearing are the digital -> analogue converters firing up, and/or the word clock syncing...
     

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