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Old January 19th, 2012, 05:24 AM   #1
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Camera mounted mic

Hi:

I've read through the posts in this forum, and from what I can understand a shotgun mic is generally recommended for outdoor use and a hyper cardioid for indoor. But does this recommendation make certain assumptions on mic placement, use of booms or stands?

I know a camera mounted mic is sub-optimal, but it's very practical when you're a one-man crew or if there is simply not time to rig mics on stands, so it's a compromise I have to make.

So, assuming a camera mounted mic as the only mic, that means:

- I can't follow a subject across the frame, I need a mic that pickups well across the whole frame, without falloff or rolloff of certain frequencies.
- (slightly) O.S. pickup is not entirely undesirable, you'll want to hear it coming.
- Undesired noise will mostly be camera operator who will be close to the mic, so 180 pickup should be minimal.

I don't see these requirements be different for indoor or outdoor recording. The shotgun seems too directional, when one can't follow the subject across the frame, so a cardiod or hyper would do, but the hyper picks up more at 180. Also, the hyper I have looked at does not pickup all frequencies equally off axis.

So, I'm inclined towards a cardioid mic as the generic all round mic for camera mount, or did I miss some point?

Thanks, Erik
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Old January 21st, 2012, 05:06 PM   #2
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Re: Camera mounted mic

I have used a number of cardioid and hypercardioid mics mounted on-camera when it was a necessity for the situations you have described.

A few important points:
The mic should have a moderately strong output, not the low output of most vocal handheld mics (unless you're in a very loud environment).
It should have a cylindrical body, again not like the tapered body of most vocal handheld mics.
The mic's power requirements should match your camera, either phantom power of the correct voltage or the capability to use an internal battery if you don't have phantom power.
Good wind protection is important such as a FatCat small furry cover for mics this size.
Low handling noise and the ability to fit in a small diameter shockmount are also important.

Some mics I have used mounted to the camera or to a bracket that also holds the camera:
AT873r hyper, ATM-31a cardioid, K6/ME64 cardioid, AT2021 cardioid, NT5 cardioid, AT3031 cardioid, C480/CK61 cardioid or CK63 hyper, AT4053a hyper, AT4021 cardioid.

The AT875 very short shotgun also works well mounted on-camera because it behaves more like a hyper and less like a typical shotgun of the past in this lower price class.
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Old January 21st, 2012, 06:23 PM   #3
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Re: Camera mounted mic

Quote:
Originally Posted by Erik Norgaard View Post
...
- I can't follow a subject across the frame, I need a mic that pickups well across the whole frame, without falloff or rolloff of certain frequencies.
- (slightly) O.S. pickup is not entirely undesirable, you'll want to hear it coming.
- Undesired noise will mostly be camera operator who will be close to the mic, so 180 pickup should be minimal.

I don't see these requirements be different for indoor or outdoor recording. The shotgun seems too directional, when one can't follow the subject across the frame, so a cardiod or hyper would do, but the hyper picks up more at 180. Also, the hyper I have looked at does not pickup all frequencies equally off axis.

So, I'm inclined towards a cardioid mic as the generic all round mic for camera mount, or did I miss some point?

Thanks, Erik
A couple of points to consider...

In general the less directional the mic the closer it needs to be to the sound source in order to provide isolation from the surrounding environmental noise. Cardioids need to be closer than hypercardioids which in turn need to be closer than shotguns. Omni's need to be the closest of all. For a cardioid to pick up a normal volume speaking voice at the level required for a quality recording and louder than the surrounding noises, it needs to be about 8 to 12 inches from the speaker's mouth. You're not going to want to shove the camera that close into someone's face. With the camera/mic farther away, the voice is lower and getting a better level by increasing the recording gain means you're also increasing the background noise to the same degree you increase the voice level, running an impossible to win race - with increased gain you now have loud lousy sound instead of soft lousy sound.

It's not just the camera operator who makes noise, the camera does too. Zoom and focus motors, hands on controls and handles, etc. These sounds are being generated just inches away from the mic and will not generally be in the mic's pattern nulls. A cardioid will pick these up perfectly.
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Old January 21st, 2012, 07:10 PM   #4
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Re: Camera mounted mic

If you have the mic that far away from the sound source, it probably isn't going to make as much difference as you think.

Last edited by Richard Crowley; January 22nd, 2012 at 03:06 PM.
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Old January 21st, 2012, 10:38 PM   #5
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Re: Camera mounted mic

Hi Erik
For general ambience audio and also one-on-one interviews at weddings I use a Rode Videomic on both my cameras! They have a really decent output and also seem to be able to punch thru a lot of background noise too!! (Wedding venues with 100 people all talking is a tough gig but as long as you are less than 2 m away you get really good audio from the Rode.

Just my 2 cents worth..been using them for many years and no regrets !!

Chris
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Old January 22nd, 2012, 12:37 AM   #6
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Re: Camera mounted mic

I am also using RODE VideoMic for all my DSLRs for on-camera mic. They did a great job.
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Old January 22nd, 2012, 06:17 AM   #7
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Re: Camera mounted mic

in almost all cases I use a hypercaroid on my camera (C300/CK93 combo) and for 99% of my run and gun it works just fine as a "general purpose" mic. whether its a wedding or a seminar and I'm running around getting some hot interviews. Obviously I'm not using it to record the main platform of a seminar (I get a feed from the board but thats a different discussion).
Whether its on the camera or a boom the hyper is my mic of choice.
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Old January 22nd, 2012, 06:23 AM   #8
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Re: Camera mounted mic

Hi:

1st, I'm not a pro and nobody will expect pro-sound, that's not to say that I do not strive to get better results, but I have to try to get the best results with what I have at hand.

Not spending time to rig and not having cables to trip over is preferable when shooting family and other events. People appreciate the video, as long as I don't get in the way of them having fun. For vacation/travel, traveling light and rigging fast is the key to wether I get anything at all. Occasionally a friend have asked me to record a show (dance), in which case I have been able to pull sound from the mixer, or overlay in post.

Quote:
Originally Posted by Erik Norgaard View Post
- I can't follow a subject across the frame, I need a mic that pickups well across the whole frame, without falloff or rolloff of certain frequencies.
- (slightly) O.S. pickup is not entirely undesirable, you'll want to hear it coming.
- Undesired noise will mostly be camera operator who will be close to the mic, so 180 pickup should be minimal.

I don't see these requirements be different for indoor or outdoor recording.
Quote:
Originally Posted by Richard Crowley View Post
You may want to hang around this (and other similar) production sound forums a while longer and see if that is still your perception.
OK, I readily admit that I'm no expert in this field.

With regards to pickup across the entire frame I think that requirement is the same regardless of indoor or outdoor recording when you've only got one mic and it's fixed on the camera.

As to O.S. I was imagining, say, a truck driving by and subject covering her ears or shouting, to cut through the noise. There may be a point to how our brain work and helps filter that noise when there, compared to seeing the same on video.

As for the last point, after going tapeless even putting my ear close to the camera I hear no internal camera noises from servos or similar while zooming, using the focus ring does generate a little bit of noise, but the main camera noises are from my fingers handling the camera. I think my breathing will be more of an issue, which is why I consider the 180 pickup, but practice may prove me wrong.

I have an AT897 shotgun mic. The problem is that while cameras get smaller, mics don't, the physical size of the mic is related to the pickup of the mic. Now the AT897, camera mounted, actually gets in the frame on my XF100 when using the wide angle zoom. Given my first point above, I started thinking maybe I was wrong to get the shotgun in the first place.

So, I have been looking at something that will keep out of the frame, currently looking at either AT4051b (cardioid) and AT4053b (hyper). My doubts about the hyper is that the off axis fall off is frequency dependent, where as with the cardioid all frequencies fall off equally.

Thanks again.
Erik
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Old January 22nd, 2012, 08:07 AM   #9
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Re: Camera mounted mic

Hey Don

The Rode Videomic is a Super Cardoid as opposed to your Hyper Cardoid so it has more front pickup and less rear pickup (the rear pattern on a hyper is larger) This works better for me as I'm almost always recording audio in front of the camera. For events I figured that would be a better fit.

However if you need to grab audio behind you as well then a Hyper would be a bit better. When I'm filming dancing I do notice a distinct drop in level when I'm on the same side of the dance floor as the DJ's speakers so I tend to stay away from that area unless the DJ has widely spaced speakers. If you do have stuff like music behind you then the Hyper would do a better job!! Then again most DJ's are so loud it doesn't matter.

Chris
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Old January 22nd, 2012, 10:56 PM   #10
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Re: Camera mounted mic

Any comment on operator mounted mics? I did see mention of a stereo head mounted set somewhere. Head mounted shotgun anyone?
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Old January 23rd, 2012, 04:00 AM   #11
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Re: Camera mounted mic

Quote:
Originally Posted by Shem Kerr View Post
Any comment on operator mounted mics? I did see mention of a stereo head mounted set somewhere. Head mounted shotgun anyone?
Every time the operator looks at a different part of the scene his head would turn and the mic would shift, taking the subject off-mic. Also, it is a myth that shotguns let you work as far away from the subject as one would normally have the camera operator standing. They do not. While their suppression of off-axis noise lets one boost the gain s tad and thus work a little farther away, they do not magnify distant sounds at all. For proper dialog recording even a shotgun needs to be no more than about 18-22 inches away from the talent. The quality begins to drop off as soon as you get farther out than that. Unless you put a lav on the talent, getting the mic close enough to the talent for optimal pickup usually means a boom and that in turn usually means someone to operate it. It's not a matter of operator preference, one needs to let the laws of physics that govern the setup necessary to get the desired results to dictate one's working style.
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Old January 27th, 2012, 10:41 PM   #12
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Re: Camera mounted mic

Erik,

Sometimes a picture is worth a thousand words.

Try this. Dropbox - Ty Ford Mic Tutorial VIdeo.mp4 - Simplify your life

Regards,

Ty Ford
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Old January 28th, 2012, 06:09 AM   #13
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Re: Camera mounted mic

Quote:
Originally Posted by Steve House View Post
Every time the operator looks at a different part of the scene his head would turn and the mic would shift, taking the subject off-mic.
Yes - I have seen this on the TV many times when a piece is shot by unprofessional people. The reporter is talking and the camera pans away to what he/she is talking about and the dialogge goes completely as the mic. is now pointing elsewhere.



Quote:
Originally Posted by Steve House View Post
Also, it is a myth that shotguns let you work as far away from the subject as one would normally have the camera operator standing. They do not. While their suppression of off-axis noise lets one boost the gain s tad and thus work a little farther away, they do not magnify distant sounds at all. For proper dialog recording even a shotgun needs to be no more than about 18-22 inches away from the talent. The quality begins to drop off as soon as you get farther out than that. Unless you put a lav on the talent, getting the mic close enough to the talent for optimal pickup usually means a boom and that in turn usually means someone to operate it. It's not a matter of operator preference, one needs to let the laws of physics that govern the setup necessary to get the desired results to dictate one's working style.
A short gun mic. at 22cm picks up the same sound as a cardioid at 17cm or an omni at 10cm - so a gun mic. just doubles the distance that you would use for an omni mic.

Not a lot of people realise this - unfortunately.
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Old January 28th, 2012, 10:06 AM   #14
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Re: Camera mounted mic

John:

That's a great chart!

For clarification, when you say "picks up the same sound" are you talking about sensitivity (or gain) in the forward direction? (Without regard to off-axis rejection.)

I would think the ratio of on-axis to off-axis pickup would be much more complex, depending on the frequency and direction of the off-axis source.
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Old March 25th, 2012, 05:38 PM   #15
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Re: Camera mounted mic

Quote:
Originally Posted by Erik Norgaard View Post
Hi:

I've read through the posts in this forum, and from what I can understand a shotgun mic is generally recommended for outdoor use and a hyper cardioid for indoor.
Just a small technical note here. Shotgun mics may actually use a hypercardiod capsule ( or sometimes a supercardioid capsule), but it is the interference tube and it's phase cancellation that allows the mic to reject the majority of sound to the sides of the mic. So a shotgun mic can actually still be a hypercardioid mic, however, a hypercardioid mic isn't necessarily a shotgun mic..if that makes sense.
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