Recording loud concerts with minimal gear?
February 22, 2011 3:41 PM   Subscribe

I've got a good video-capable DSLR camera, and a good external microphone for it. But when I'm at concerts, the audio is blown out. Help?

There are a couple of existing questions out there on MeFi that cover general "How can I get good audio for my camera" issues. I'm looking to solve a specific problem: my Canon 5DmkII and accompanying Rode video mic do a great job unless I'm near a loud audio source, like a speaker at a concert. Are there any intermediary boxes I can hook up between the mic and the camera that will compress the audio? Am I asking for the impossible?

I'm new to this side of things, after spending a lot of time with still photography, and I'm hoping that the MeFi hivemind knows some tricks that can help...
posted by verb to Technology (14 answers total) 3 users marked this as a favorite
Well I mean if you're recording concerts and potentially roaming around, close to speakers, or near a cheering crowd, you don't want to be recording on-board anyway. And I'm not an audio expert but I don't think compression addresses a blown-out recording. The Zoom H4N is a popular standalone, multitrack recorder that a lot of people use with the 5D.
posted by phaedon at 3:52 PM on February 22, 2011

Response by poster: phaedon, that might well be the issue. I'm inexperienced enough with this side of things that I'm almost certainly doing things wrong. I'm using an external mic, but the camera is definitely doing the actual recording. Recording external audio mean mixing the audio and video together after the fact, right?
posted by verb at 3:55 PM on February 22, 2011

Best answer: What firmware are you on? v. 2.0.4 on (I think it's on 2.0.8 now) should allow you to adjust audio levels. Try some tests with the mic and see if that makes any difference, if you haven't already. Do you have any samples we could listen to/watch?
posted by therewolf at 3:55 PM on February 22, 2011

I'm probably the wrong guy to bother answering this seeing as how I've tried using neither of those devices specifically. However! I have done a bunch of audio recording of varying kinds...there is no question that speakers at big loud concerts are pushing a whole lot of db. I'm pretty sure that condensers tend to be more sensitive to loud noise (vs. say, dynamics) and do not handle it as well, even if you pad the thing as much as you can. Googling shows me that your pro Rode shotgun condenser there does have a -20 pad you can use... if you haven't tried that already.

I don't know much about mics specifically designed for video cameras, but I'd think you'd at least need a decent limiter on that guy, in addition to the pad, if that's even going to work. I think this is what you're asking about. You could probably rig something up. I doubt that there's a limiter built into the audio stuff of the 5DmkII, but I don't actually know. So you could try something like that, but I think you'd be better off with a different mic. Or as phaedon says, use a separate rig for audio entirely.

Either way, I suspect there's got to be a list somewhere of semi-'standard' mics that people use, for doing recordings the likes of which you are describing - like super loud live concerts w/ video : ) Dunno if they're suitable for your Canon, tho.
posted by bitterkitten at 3:56 PM on February 22, 2011

Response by poster: therewolf, this clip is one that was recorded at a distance with a telephoto lens, while this one was recorded with a shorter lens, closer to the stage.

I'm running older firmware -- I hadn't realized that there were improved audio features in the newer versions, and I'll have to check them out.... Thanks!
posted by verb at 4:00 PM on February 22, 2011

Best answer: Verb - yes. And there's a piece of software called PluralEyes that automates the synching process. I've never used it, but everyone I know that has swears by it. I believe it takes the audio scratch from your camera and syncs it up with your external recording. Very precise.

On-camera adjustments aside, if you record with the Rode attached on top of the camera and you're moving around that's going to affect your recording in a very noticeable way. Why deal with these problems in post? With the Zoom you can run multiple mics and position them in a more appropriate way. Or, if you have some pull with the band or the venue, you can plug into the mixer.
posted by phaedon at 4:01 PM on February 22, 2011

Response by poster: On-camera adjustments aside, if you record with the Rode attached on top of the camera and you're moving around that's going to affect your recording in a very noticeable way. Why deal with these problems in post? With the Zoom you can run multiple mics and position them in a more appropriate way. Or, if you have some pull with the band or the venue, you can plug into the mixer.

That's probably a good move. My initial thought was that I wanted to capture the crowd noise and the general sound of a live show -- and when it wasn't clipping madly, that's exactly what I got. I've installed te new firmware and will see how the audio level adjustments help at the next show, and am taking a look at the Zoom H4N... Thanks!
posted by verb at 4:32 PM on February 22, 2011

Sounds like the mic itself is clipping / overloading in the second clip.

In the first, I can't tell what's going on. It's like there is no bass response at all. Maybe that's an effect of the shotgun setup?

So my guess is that the mic has a very narrow dynamic range. (As well as a pretty narrow frequency response?)

So, what you need to do is find a mic that has enough dynamic range to tolerate the boom from the bass, but also still be able to "hear" when it gets quieter.

Then you need to test it with the camera and see if you need to do any processing (limiting, compression) between the mic and the camera. With a different mic better suited to that environment, you might not need to.

Because no amount of processing is going to be able to fix a signal that is getting messed up in the mic. And that's what I think is happening.
posted by gjc at 4:36 PM on February 22, 2011

Check out this forum - there are some very knowledgeable people there.

Basically, what you need to do, is get electret mics caps (best ones are Panasonic WM-60/61) and a battery box to power them. Ditch the mic you're already using. You can make the battery box yourself with a 9V battery, some basic components and a little bit of circuit board. There's a good how to here. Combined with a good line-in and lossless recorder, this is the best way to record high SPL amplified gigs bar befriending the guy on the desk.
posted by turkeyphant at 4:45 PM on February 22, 2011

I am no expert on sound recording, but a recent post by Rich Juzwiak on his blog fourfour mentioned the Zoom Cam and how it is optimized for concert recordings. I just e-mailed him and asked him what specific camera he meant, and he pointed me to this product, presumably from the same manufacturer phaedon mentioned. Here is a sample of the audio coming out of that camera. That might give you an idea of how Zoom performs in these situations.
posted by therewolf at 4:48 PM on February 22, 2011

You've got a great video capture device (5DII) but the audio capture on it is fair at best. Most people who want great audio from a DSLR are recording externally to a device like a Zoom H4N or H1 and then syncing in post with PluralEyes. So keep your Rode- you'll use it with your external audio capture device. Also be sure to use the 5DII's onboard mic so PluralEyes has something to sync to.
posted by gen at 5:01 PM on February 22, 2011 [1 favorite]

Best answer: You might be interested in Magic Lantern -- it gives you onscreen audio meters and live headphone monitoring, as well as adjustable gain while recording so that you can fine tune the levels. The stock 2.0.x firmware updates from Canon give you manual gain if you want it, but without the meters, monitoring or live adjustments. Plus you can write your own code to run inside the camera.

The pre-amps in the 5D are quite poor, so for best audio results the internal analog gain should be at 0 or 10 dB, and an external pre-amp used. The Rode mic has its own preamp that is slightly better than the cameras, but not as good as something like the Juicedlink cx321 or cx211.
posted by autopilot at 5:37 PM on February 22, 2011 [1 favorite]

Response by poster: I feel a little lame marking so many "best answers" but the information here has really helped a lot. i've upgraded the firmware on my camera and will be trying out a test run with the built-in level adjustment, and I'm also going to take the latest build of Magic Lantern for a spin as it allows on-screen metering to spot the clipping as it happens, rather than the morning after the show.

I'm also investigating the Zoom recorder and Pluraleyes, as it sounds like they're a solid long-term solution if I'd like to do more of this. Thanks, everyone! I'll try to pop back in and update the thread when I have a chance to record some additional shows based on the advice you've given.
posted by verb at 11:00 PM on February 22, 2011

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