Canon 5D mk2 audio hiss: is setting ext mic's output to +20db the best solution?

Discussion in 'Digital Video' started by atlanticza, Dec 15, 2011.

  1. atlanticza macrumors 6502a


    Jul 18, 2008
    Cape Town
    Audio hiss appears to be a problem, but I came across a 'solution' which claimed that if one has an external mic like a Rode Videomic Pro attached to a Canon 5D mk 2, simply set it to +20 db, then turn down the manual gain on the camera to about 20 to 25%. (The pre-amp on the mic is far more efficient than the camera's, apparently.)

    Has anyone had experience of this, or could perhaps offer a better solution?
  2. careypo macrumors member

    Oct 15, 2011
    Most people that shoot with DSLR use external shotgun microphones. There too much noise with the onboard mics.
  3. handsome pete macrumors 68000

    Aug 15, 2008
    I believe he's talking about shooting with external mics already, not the on-board mic.

    I can't help with an answer though. When using DSLRs I've always recorded sound separately and synced in post.
  4. Steve-F macrumors member

    Jun 17, 2009
    I've used my Canon 60D with the Rode Video Mic Pro fairly successfully. Yes I followed advice from others to ramp up the microphones gain and turn down the cameras audio input. I've also used a Sony tie clip mic with no gain and had good results.
    The main issue is no monitoring of audio when recording so most resort to an external recorder.
    Might be worth exploring the Magic Lantern software hack to release some of the extra audio features.

  5. floh macrumors 6502

    Nov 28, 2011
    Stuttgart, Germany
    As you have already noticed, your hissing problem most probably stems from the preamp of the camera. All microphones need to be pre-amplified before the signal is recorded. And the amplifiers vary greatly in performance. Since DSLRs are mainly made for photography, the mics are crappy, but also the preams for external signals will not be best of their class.

    If you have an external microphone that has an amplifier integrated and produces less noise, crank it up as high as you can. You additionally gain from having a stronger signal earlier in the sound line (meaning there will be less loss from your cable etc.). If you don't have such a mic (I don't and I've hardly ever seen it), you can go with one of two options if the hissing is bugging you:

    1. You could get an external recorder (e.g. the Zoom H4n), which will most likely have a grounded connector (XLR) and better preamps. You will need to sync the audio in post.

    2. You can buy an actual mic-preamp. Those are usually expensive, because you only buy them for high-end stuff. But even a cheap mixing console will most likely have better preamps than your DSLR camera.

    Hope that helps.
  6. atlanticza thread starter macrumors 6502a


    Jul 18, 2008
    Cape Town
    Many thanks for the input. I'm using the Rode Videomic Pro as the external mic, and after some testing, I've found that the best balance (and minimum hiss) is when I set the Rode's output to 0db and the camera's manual audio level to about 75% peak. Results are very good.
  7. Photoshopper macrumors regular


    Mar 24, 2010
    Floh is correct in describing the issue as being the crummy preamps in a dslr.

    One moderately-priced solution is using a preamp like the JuicedLink DS214 to provide clean gain to the camera, and throttling down the camera's gain to the absolute minimum.

    I use one with a Rode svm on my 5DII, and while it's not really a professional solution, it's way ahead of doing it with just the camera and a mic.

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