Part 2 where I show how to create a cable that will disable the AGC (with the addition of a noise source).

Note: I tried a new render encoder on this video and it appears that the audio is a little out of sync. (I used the Sony AVC *.mp4 codec – this also creates a file 3 times larger than the MainConcept encoder) – yes, I am always testing. 🙂

Sorry it has taken me a bit longer to publish part two of this hack to disable your AGC on your Canon DSLR (7D, T2i 550D).

Our family took a trip to Ouray Colorado to visit some friends over the 4th of July weekend where I took hundreds of photos and tons of video clips.

I am getting more and more comfortable taking pictures and video with just one camera now.

Anyway back to the hack to disable the AGC.

If you haven’t yet, go back and watch part one of this hack where I demonstrate the differences between the AGC enabled and disabled.

Part 2

From Tarvi Roos For the Mac Final Cut Pro Users

To create this adapter you will need two stereo 1/8″ jack connectors and one 1/8″ stereo plug. That is about $8 in connectors.

I had some old West Penn 2 conductor #22 gauge stranded shield cable lying around that I used for the audio cable.

You don’t need something as professional as West Penn wire but you should buy the best cable you can find because we are unbalancing the Rode Videomic which means you will not want to remote this microphone more than 20′ away because it will probably pick up a lot of electromagnetic noise around other electrical devices. I have remoted this cable over 10 feet without any noise or frequency response issues.

Strip back the wire and solder the red wire to the tip, black wire to the ring and the shield to the sleeve.

On the connector that will plug into your Canon camera, connect the red wire from the mic connector to the tip of the 1/8″ plug and the red wire of the mp3 player to the ring of the 1/8″ plug. Clip off off the black wire for each. Then solder both shields to the sleeve to the 1/8″ plug.

You might think you can just buy one of these y-adapters from radio shack like I did but you can see that the shield is missing from the connector which is required for this to work so don’t waste your money on this connector.

Then connect your Videomic and your mp3 player and then connect to your T2i 550d or 7d.

What I liked about having an mp3 player is I can accurately reset my level adjustment on my mp3 player each time. You can use many other things for this like a metronome tone or even a pick noise generator.

You need to accurately set the level each time you record. If the level is to low it won’t squash the AGC all the way but too much and you can get cross talk in to the mic channel. Even though I can’t hear anything above 16k since I was a teenager you can still hear some of the sub harmonics of the tone but it is not too annoying on playback on the small t2i speaker.

Download the 19kHz tone (one hour long). Right click and “save target as” (unless you are really young you will not be able to hear this).

That is pretty much it, watch part I on how to processes the audio tracks.

Canon T2i has been discontinued, replacement is the Canon T6i: B&H | Amazon


Check out my course I have to get you up to speed quickly with your camera.

Some Picture from the July 4th Weekend

Cat in Log Cabin

Ouray 4th of July 2010



  • That’s pretty much how I did it, after experimenting for 1 day.

    My only exception is that I have connected the ring and shield together on the female connectors, so that they constitute one wire and the second wire is the sleeve.

    Anyway, thanks for your help and videos.

  • I am in Italy right now.

    I searched for an Audio store because in regular wallmart-type store I couldn’t find those connectors. So i just found “Lucky Music” – a store with audio equipment and bought them from there.

  • Dave, this look great, thanks for posting it! Would it work to make the mp3 player end a male end so that I could just plug it directly into my iPod?

  • I have made mine like that – I use only one female plug and the other is directly male – for the player.

  • For those of us who are not so technologically inclined. I hope there is an easier workaround or someone starts selling these cables. I would buy one 🙂

  • Yes, finally a solution! Slavic, I live in Switzerland. Would you consider making one of these cables and sending it? I’d cover the costs. I’m kinda retarded when it comes to electrical DIY, so i doubt i’d come up with something useable. I guess i could try. Let me know if it’s possible. Cheers!

  • Well guys, I let’s wait for Dave’s approval here. It’s his idea and blog and he should allow this first 🙂

  • @Slavic Thanks for waiting, but please make all of these you want. I need to contact a few audio manufacturers like Hosa and others to see if they will custom build something like this.

  • Hey Dave,
    I’m on the verge of buying a t2i for video freelancing and your site has been very helpful, The AGC disable is very important to me and I will eventually get a Juicelink or h4n but in the meantime was very interested in your DIY disable idea.

    I found this cable online and wondered if it would work

    I also noticed though that you would need 2 males (one going into t2i, and one going into mp3 player) so didn’t know if you just had another male to male adapter or how you solved this based on watching the video alone.

    PS let me know if you are making them or do find any audio companies selling them.

  • @Matt you are right I should have done it with two males.

    I looked at that adapter you linked to but I didn’t see any schematics so I can’t be sure how it is wired. But for the price it might be something worth trying.

  • If someone would be willing to 1. Make one of these for me and 2. Add a MP3 player (any ol’ brand will do I suppose) with the tone already installed I will certainly compensate you for your time, materials, costs, and efforts. Please E-mail me at with a response and possible price. I don’t have the time, materials, or patience *lol* to tackle this. MUCH appreciated!!! I’m in New Hampshire USA. Thanks!!

  • Hey Dave,

    I kinda turned into a mass production factory of cables 🙂

    I think I’ll have to outsource some of the work cause i don’t manage my things 🙂



  • Thanks for this information and the links to the other videos. I ended up building the Tarvi Roos setup successfully but now I have a problem. My Rode mic recorded audio when directly connected into the camera’s 3.5mm jack (could be played back through the T2i’s built in speaker). I built and tested Tarvi Roos’ setup. Audio (tone+Rode mic audio) recorded fine. I unhooked everything and the built-in camera mic still recorded audio.

    But when I connected my Rode mic directly into the camera 3.5mm jack again after testing the AGC bypassing setup, audio will no longer record..only hissing. Any ideas? Do I need to reset something? I took out the camera and VideoMic batteries just in case. Still no audio. Audio can now only be recorded with either the built-in camera mic or when the Rode VideoMic is plugged into Tarvi Roos’ AGC bypassing setup. No audio when Rode is directly in the 3.5mm camera jack.

  • Hey Dave,

    I understand the use of being able to adjust the level of the tone signal, But how do you “Know” what is the correct level? how do you tell what is to little vs too much?

    Does this change?


  • @Al there are 30 steps in my mp3 player’s volume, I tested each step from low to high until the agc was fully suppressed and it did not bleed in to the other channel.

  • I was just wondering… rather than creating your patch cable, could a person simply use your 19kHz tone and use it in Audition to ‘squelch’ or silence that tone? I’ve had to remove hisses and background hums before in Audition and was wondering what kind of results I might get by doing the same kind of thing with your 19kHz tone with my Rode VideoMic.

    Anyways… while I’m waiting on comments I guess I’ll see if I can give it a try. 🙂

    Thanks for your videos!!!

  • @Jon — that totally worked! I’ll post up a test video in a bit.

    it sends the 19khz tone to the left channel, forcing the noise floor down, while the right channel records the usable audio — then just fill right in premiere or “right channel only” in vegas and you’re good to go!

  • Dave, Thanks for the great videos.

    I think you should try out Jon’s way. It looks like it’s gonna work.


  • If anyone finds a way to do with with normal parts please let me know and I will create another post on this. I have spent too much on audio adapters so I am not going to try since my homemade stuff works fine.

  • Hi it’s me again.

    Thanks for the reply.

    I was wondering, is there any cheap way to monitor your audio while recording?

  • Hi Dave,
    Sorry but I can’t figure out how to download the audio file.
    It appears in the center of a black screen with no way to download.
    It may well be my ignorance to this sort of download

  • Great pictures Dave!
    Keep on! you are doing a great job with your camera and mostof your videos on youtube are very helpfull.

  • hello dave thank you for all of your help but i can’t seem to download the tone… is there anything other than clicking on it that i should do?

  • I dont have a Rode microphone but i do have an external mic, but will this hack work with other external mics? I have a Audio Technica ATR-6250


  • Hi there
    What if you use the analog video output of the camera and inject it into one of the channels 🙂
    It might be too loud and we’ll get some crosstalk. Give it a try and show the results!!!

  • If the video sync signal is too loud, just add a resistor and a ceramic condenser (as a lowpass filter) until you get the right amount of “signal” into one channel!!!

  • The video mic pro has built in 20 db gain. Will that solve the abc problem without the hack?

  • Hello,
    I´ve tried the same procedure like you explained in your site, but with another microphone -Zoom H2- it doesn´t worked. By wathing the the recorded videos you can hear the 19khz noises. Can you help me please to solve this problem.

    Best greetings from Germany

  • Hey Dave,
    Your videos really helped me with learning DSLR for videos and also buying my gear.
    I was surprised that my T3i had some constant loud hiss and noise with a Rode Videomic.
    The problem wasn’t AGC because of the manual audio control, but still i follow the steps and built the AGC hack setup thinking it would stop the hiss. First I did a test with manual control and turning on and off the mp3 player didn’t change nothing to the audio (and the hiss just kept loud). Then I tried with automatic audio, just like your setting and it really worked! The AGC hack with auto audio was better than just the manual settings (with or without the hack).
    I searched on the internet about the T3i’s audio problems and found almost nothing.
    (I’ve use another solution that is recording the audio externally with a cheap camcorder and the rode mic and it is was great also.)
    Maybe if owners of the T3i (and even 60d’s) knew about this they would be pleased of the solution.
    For me, I’m sticking with the simple AGC hack with T3i’s automatic audio control.

    I just don’t know why the heck is there a problem with the manual audio control of the T3i

    Thanks a lot, man
    If you want, I can give you more details!

  • Does anyone know if this will work with the Rode Videomic PRO? I have a similar cable but all I got was a quieter hiss yet no voice with my video.

  • Hi Dave,

    your AGC-Hack is awesome. Otherwise, i wouldn’t have bought the Videomic in combination with my already brougth EOS 7D. Now i can produce a semi-professional clip with basic setup. For shure, high quality productions need external audio at all, because of this mp3 player driven gain control and no live check of the audio.

    But still: I love you for your solution.

    Ruediger Meyer
    kopfstunt media

  • Hi Dave,

    I have a Canon XL2 20x lense that I want to put in use with my Canon T2i body, but the lense doesn’t seem to fit. Any ideas on what to buy or do, to make it work ? I thank you in advance.

  • Found the cable listed on for $27.99.
    But the link for the 19 hz tone doesn’t work as you described.

    Download the 19kHz tone (one hour long). Right click and “save target as”

    Only a quick time movie comes up with no image of audio. Player doesn’t play and if it did I wouldn’t be able to tell 19 hz.(unless you are really young you will not be able to hear this).

    In order to save the quick time movie you need quick time pro which is $30.00 that’s more then the cable coasts. Can you list a web sight that I can download the 19hz for free. After all the cable is worthless without the tone. The canon 7d has no way of monitering the sound leveal. How do you set the leveal of the 19 hz?

  • I bought the cable from adorama for about $25 hooked it up with the rode mic (standard settings) Hooked it up to my t3i, using a class 10 Transcend SD card and tried to do everything here but the 19khz sine wave tone is giving the camera too much information, so my t3i automatically stops recording after 10 seconds, tried turning the 19khz sine wave down to the lowest volume, and it extended my play by a whopping 10 seconds. I felt like I wasted money and time. Am I doing something wrong?

  • @Floyd if you are comfortable installing Magic Lantern you don’t have to fool with this cable at all anymore, I created this most before ML was stable enough to use. This tone idea is actually pretty old. Also if I am not mistaken doesn’t the T3i give you manual control now any way?

  • @Dave.

    It does have manual control now. But for some reason that hissing sound is still there. I should have just gotten an H4n. I might give ML a shot. thanks Dave.

  • Hi Dave

    Really great site and your videos are first class, they have really helped me get a clear understanding of shooting video.

    Does the T4i (650d here in Northern Ireland), have AGC issues/hiss problems, and if so will this fix work?

    Thanks so much.