Magic Lantern feature Settings: how to get the best audio in-camera

on November 4, 2014

Audio has been one of the weakest features on DSLRs.  The on-camera audio is really awful, and wiring in a quality pre-amp and mic gives acceptable results at best.  Still, using single system audio will shorten your turnaround time considerably.  (If you are using a Canon 600D, this menu doesn’t appear in your Magic Lantern.  Fortunately for you, your camera has built in manual audio control.)

Analog Gain

This allows you to control how much gain goes into BOTH your channels at the same time.  You want to adjust this so that you have a recording level that is between  -24 and -12 db.  The higher you can go, cleaner your sound, but you also risk clipping if someone shouts or there is a loud truck passing by.  If you keep it very low, you won’t have to worry about clipping, but you will have to bring up your volume levels in post to make sure you can hear your talent, and doing that will also bring up any background noise that was in the shot as well.  You best bet is to get the talent as close to the mic as possible and set your levels so that they don’t clip, even if they were to shout or scream.

L-digitalGain and R-digital Gain

This is to digitally control how much gain is going into each channel  It’s a nice feature to have, and can be handy if you have multiple people on different lav mics that are feeding into the same source.

This is a very rudimentary feature set.  If you have to adjust gain- you are much better off doing it through your pre-amp or recording device that has dedicated hardware to give you a cleaner sound.

Input source.

This lets you determine where you want your recording sound to come from:

Int mic– the on board camera mic

L: Int R: ext– This is if you want to use an external recorder and also use a mic running into your camera

External Stereo – for using mics that are plugged in from an outside source.

L:int R:balanced – this will use the internal mic to record on the left channel, and use the LEFT AND RIGHT channels from your recorder as a single channel in the mix.

Auto int/ext : the camera detects when a mic is plugged in and does the thinking for you.  This is a good default to set.

Wind Filter

This is a digital high pass filter.  Use this if you are shooting outside and you just CANNOT get clean audio and you have exhausted all your other options. (Have you tried blocking the wind?  Deadcat? Putting a sock over your boom mic?)

Mic Power

This is the power to your internal mic and some of your external mics.  This is best left ON if you plan on recording scratch audio with your on board mic to match up with “good” audio later.


Automatic Gain Control

This is a digital algorithm that your camera uses to try to even out the sound levels.  It’s messy and not very good.  Just turn it OFF and adjust your audio with the ANALOG GAIN.

Headphone Monitoring

This lets you monitor your audio through headphones using and A/V cable.

(Magic Lantern notes that you should DISABLE THIS if you are monitoring using an SD monitor)

Note- this is NOT just a headphone cable that you plug into your camera.  You need a special cable like this one from Sescom, or use your original Canon cable hooked up to an RCA – 3.5mm jack)

Output Volume

This is just for you to adjust how loud the sound is coming in through your headphones.  It’s just for your listening enjoyment and has no actual bearing on how loud the camera ia recording the audio.

It’s best not to overthink the audio from your DSLR.  Even at its best, it is passable.  If you are just doing run ’n gun, and you plan on playing some music behind your final edit, it is totally passable- without question.  If you are doing any kind of narrative work and you are setting up your shots carefully and deliberately- take the time to do your audio right.  People will sit through some mediocre visuals.  People will turn something off if the audio is bad.