Rode Videomic Pro and 7D Any benefits given the 7D's AGC?

T

the_wallbanger

Member
I have a Zoom H1 and a lavalier for interviews, but I was considering the Rode Videomic Pro for a general purpose microphone.

Does the Videomic Pro's level selections (-10, 0, +20) and high pass filtering have any benefit when paired with the Canon 7D? Afterall, wouldn't the 7D's AGC cancel out any manual adjustments you've selected on the mic? Any one try this combination out? Any recommended settings?

Am I wasting good money by paying extra for the Pro's manual level selection if the 7D just overides it with Auto Gain?
 
The Rode Videomic Pro is almost certainly better than the built-in mic on the 7D. However, you're not going to get "pro" results recording with a battery powered microphone mounted on a hot shoe using 1/8" jacks and going into an AGC circuit. So it's probably a step up, but nowhere near what you're going to get with a dedicated field recorder and a proper mic.

If you want good quality, stick to XLR, phantom power, and manual level controls. The H1 is going to sound better than the 7D's AGC circuit for sure.
 
robotsound said:
The Rode Videomic Pro is almost certainly better than the built-in mic on the 7D. However, you're not going to get "pro" results recording with a battery powered microphone mounted on a hot shoe using 1/8" jacks and going into an AGC circuit. So it's probably a step up, but nowhere near what you're going to get with a dedicated field recorder and a proper mic.

If you want good quality, stick to XLR, phantom power, and manual level controls. The H1 is going to sound better than the 7D's AGC circuit for sure.
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+1

For what it's worth, I use a RODE VideoMic with my T2i. The audio is crap due to the camera's poor audio circuitry and the AGC, but what it does help me with is better scratch audio for syncing my double-system sound in post. Even though I won't use the camera audio in edit, I wouldn't go back to shooting with the built-in mic just because the cleaner scratch track is so much more helpful.
 
On the T2i, its actually excellent when using the Magic Lantern hack to kill AGC and raise some analog levels manually.

But, for the 7D, you're really up the creek without a paddle on audio. I wouldn't waste your money unless you are also interested in doing that trick to circumvent the AGC by playing a loud channel on the other side. Dave over at learningdslrvideo.com actually did exactly that using a Rode, a simple mp3 player (loaded up with a loud and long static noise file) and a plug from radio shack to wire up the separate channels with.

Doing that, you can get pretty decent audio, but without Magic Lantern or an external recorder, you can't live monitor your audio with headphones, which is usually pretty dangerous if its your primary audio track.
 
dishe said:
On the T2i, its actually excellent when using the Magic Lantern hack to kill AGC and raise some analog levels manually.

But, for the 7D, you're really up the creek without a paddle on audio. I wouldn't waste your money unless you are also interested in doing that trick to circumvent the AGC by playing a loud channel on the other side. Dave over at learningdslrvideo.com actually did exactly that using a Rode, a simple mp3 player (loaded up with a loud and long static noise file) and a plug from radio shack to wire up the separate channels with.

Doing that, you can get pretty decent audio, but without Magic Lantern or an external recorder, you can't live monitor your audio with headphones, which is usually pretty dangerous if its your primary audio track.
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I do have the T2i hack.
 
Ok back to the 7D case. Obviously having the hack on the t2i giving you manual controls plus the -10 to +20 gain controls on the mic itself is going to sound good.

The main thing people want to know is if this +20dB gain on the mic itself will combat the AGC on the 7D, enough obviously not completely, to kill a good bit of the hiss and give you much cleaner audio.
 
iplaysnowboards said:
Ok back to the 7D case. Obviously having the hack on the t2i giving you manual controls plus the -10 to +20 gain controls on the mic itself is going to sound good.

The main thing people want to know is if this +20dB gain on the mic itself will combat the AGC on the 7D, enough obviously not completely, to kill a good bit of the hiss and give you much cleaner audio.
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On its own, no. That's what I was trying to say before.

However, you could still do it the way Dave Dugdale did, again as I mentioned before, and "cheat" the AGC using some spliced wires and an mp3 player. That together with the Rode mic would give your cam very decent audio even on the 7D.

You can see his before and after test here:
http://www.youtube.com/watch?v=fnQAd23wFes&feature=player_embedded

As you can see, even with the Rode mic, there is still hissing in between talking. But after the agc disable trick, it sounds much cleaner. This is totally doable on a 7D.

Edit: You can read his whole post about it here:
http://www.learningdslrvideo.com/t2i-7d-disable-agc-rode-videomic/
 
Yea i've heard about that before. Doesn't it basically "kill" one channel of audio though? Basically one will have the tone you are pumping into it. So in post you most delete that channel and duplicate the other?

And I realize this is a very doable little trick. I was just wondering if the +20dB gain on the VMP would help to keep the hiss down that much more making the VMP worth the extra money over the VM. This being straight into the camera, no external recorder or hack to disable the AGC.

My plan was to get something like the VMP and use it straight into the camera for a while and then possibly get something like the H4n to feed the mic into.
 
iplaysnowboards said:
Yea i've heard about that before. Doesn't it basically "kill" one channel of audio though? Basically one will have the tone you are pumping into it. So in post you most delete that channel and duplicate the other?

And I realize this is a very doable little trick. I was just wondering if the +20dB gain on the VMP would help to keep the hiss down that much more making the VMP worth the extra money over the VM. This being straight into the camera, no external recorder or hack to disable the AGC.

My plan was to get something like the VMP and use it straight into the camera for a while and then possibly get something like the H4n to feed the mic into.
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Again, NO.
Having a gain on the mic makes ZERO DIFFERENCE to AGC. I apologize if I did not make this clear. None of that will make any difference, PERIOD. All it will do is raise the volume less when you are talking because it will be already amped a bit, but the end result will be the same volume (that's what AGC does, it normalizes to the volume it *thinks* you should have), therefore would sound the same with the preamp vs not.
In other words: There will still be an awful hiss when you are not. No matter what. I don't know if I could make this any more clear.

THE ONLY WAY TO BEAT AGC AT ALL ON THE 7D IS WITH THE METHOD DESCRIBED ABOVE.

As far as "killing" one channel of audio- the mics you are discussing are all one channel Mono. No stereo. Which means one side is usually blank anyway (or doubled, depending on the connection and mic, however in most cases one side is blank).
Generally, the accepted practice when I shoot interviews with a lav mic is to record on the left channel input, then delete the right in post, making the audio mono (which is how it is recorded anyhow). This is no different, except that you are "killing" one of the channels with noise instead of it being blank before you delete it.

If you are planning on recording two channels of audio, that's a different story. But I gotta say- some of the most annoying videos I've seen by amateurs on youtube are the ones with dialog only coming out of one speaker. Apparently some people plug an external mic into their camera, and then don't realize it is only recording to one side. Then, they edit and just post the whole thing like that. Drives me crazy, especially when they have intro music that is stereo, then suddenly all the dialog is on one side. At least using the noise method to kill AGC will prevent people from making that mistake!
 
Ok i'm still a little confused. I thought when you heard the one sided audio it was because they did the audio hack and didn't duplicate the audio so it is playing on both sides? I'm super confused.

I thought when you did the hack the noise is one side and good audio is on the other. So you would delete the noise and duplicate the good audio to come out both sides? Sorry if i'm being a pain I would just like a little clarification.
 
iplaysnowboards said:
Ok i'm still a little confused. I thought when you heard the one sided audio it was because they did the audio hack and didn't duplicate the audio so it is playing on both sides? I'm super confused.

I thought when you did the hack the noise is one side and good audio is on the other. So you would delete the noise and duplicate the good audio to come out both sides? Sorry if i'm being a pain I would just like a little clarification.
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Ok, forget the hack, forget your camera. The one-speaker audio thing I'm talking about is NOT exclusive to DSLRs, or any camera in particular.
I'm talking about amateurish videos taken on standard video cameras. The camera has built in mics that record a left and right channel, but everyone knows you'll get better audio if you plug in an external mic, right?

But when you plug in a mic like the Rode or a wireless lav, etc, you are recording in mono since it is a single mic. The camera records in stereo, but you are using a single mic.
With a camera like the DVX100, you pick either the left or right to plug the mic into (there are 2 XLR inputs on those cameras, one for left and another for right), and just go. Then, when you put all your footage into an NLE, you have one side that is populated with audio from the mic, and the other side is usually blank or set to record audio from the internal camera's mic (useful for scratch track sometimes).

If you don't really know what you're doing, or you are sloppy, you'll find people leave the captured audio all on one side and never remove the blank other side. That's really annoying, especially if they used stereo music or even worse, switched which input they were using on some takes! Then you end up with audio on one speaker half the time, than switched to another later, then music on both. GAH!!! Those drive me nuts.

This has nothing to do with DSLRs, hacks, your camera, the mics you are asking about, or anything. It has to do with the fact that most modern cameras record stereo audio, but a standard mic is recording mono.

Therefore, deleting a channel of noise to make the "good" channel fill both sides isn't actually any extra work in post at all.*

*EDIT: The truth is, it is possible to set cameras like the DVX to record one input to both channels right from the camera, assuming you don't want the camera's audio as a scratch track. I don't usually do that, and it appears that many of the camera operators I've worked with don't either. I always kind of assumed everyone deletes the other channel in post.
 
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By the way, grabbing only the left or right channel is not difficult.
In Sony Vegas, its 2 mouse clicks (right click on audio, hit Channels, pick left or right).

In Premiere, select clip in the bin, go to Clip->Audio->Source Channel Mapping.
 
Ok just so it get this straight, and thank you for your patience and help, so let's say i have my 7d a rode mic and do the hack feeding a tone into one of the channels to dumb down the AGC. Then in post all i have to do it delete the tone channel and that will fill both right and left speakers with the "good" audio?

And I'm using FCP also. I just don't have access to this stuff yet so there is no way for me to do a trail and error type experiment to figure it all out yet so I really do appreciate your help.

And one more quick thing. Do you think the VMP with an audio hack would be that much better than just the VM with hack? With the built in gain control to the mic, smaller form factor, and rode claiming better audio it does seem worth the extra money does it not?
 
iplaysnowboards said:
Ok just so it get this straight, and thank you for your patience and help, so let's say i have my 7d a rode mic and do the hack feeding a tone into one of the channels to dumb down the AGC. Then in post all i have to do it delete the tone channel and that will fill both right and left speakers with the "good" audio?

And I'm using FCP also. I just don't have access to this stuff yet so there is no way for me to do a trail and error type experiment to figure it all out yet so I really do appreciate your help.

And one more quick thing. Do you think the VMP with an audio hack would be that much better than just the VM with hack? With the built in gain control to the mic, smaller form factor, and rode claiming better audio it does seem worth the extra money does it not?
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That I can't tel you... You're now diving into FCP specific questions, and it is not my platform of choice so I don't know. Perhaps someone else here can chime in with specifics. Or, if you already have FCP, load up a clip that was recorded in stereo and experiment!

What you are essentially going to with the noise trick is take a track that is currently stereo (2 channels) and turn into one that is mono (only one channel- in this case, only the one that had the mic data on it). Mono audio is neither left nor right so it will play back on both speakers.
Think about it- not everything on your computer is stereo, yet it always plays on both speakers. Take for example a Skype phone call.

If you are rendering the video out to a format with stereo audio, any good NLE will put the mono audio on both sides. I think a common example of this is recording voice narration using FCP's voice over tool- I've seen people use it to record some narration directly into the timeline using their macbook's internal mic (which is a single mono mic). Again, I can't say for sure as I don't use FCP much, but that's how every other NLE I've ever seen works.
 
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