Capturing Good Audio in a Noisy Environment

Todd Shilkin · January 21st, 2013, 10:08 PM

Hi All,

I've started a similar thread on the DVXUSERS forum, but figured that whilst there is obviously going to be some cross over of members, I may well get some different insights here, especially given the 'All Things Audio' Board.

I'm a newbie with the AC90 being my first AVCCAM, and the Rode NTG1 being my first shotgun mic.

I'm doing a fair bit of vox-pop style/ run and gun interviews in cafe/ restaurant environments, and I'm struggling to get good audio.

What I've been finding is that all of the cooking and air con equipment means that there seems to always be an underlying 'hum' or background noise, as well as the clanking of pots and dishes etc.

I was hoping that the ntg-1 would mean a more concise 'directional' recording, but I'm still finding the recordings are very noisy.

Without an audio guy and a boom mic with me, are there things I could be doing/ basic settings I should always have, etc to get the best possible sound with the least amount of background noise?

Also, should I always expect to have to some kind of NLE noise gate plugin manipulations, or should it possible to achieve good audio without the need to spend hours in post production?

Thanks in advance for your help.

Todd

Steve House · January 21st, 2013, 10:23 PM

Proximity is your friend. The closer you can get the mic to the subject the louder the voice will be in comparison to the surrounding noise. The optimum working distance for a short shotgun like your NTG-1 is about 18-22 inches. Secondly, if the axis of your directional mic is parallel to the axis of the lens, as it will be if the mic is mounted at the camera, any noise source BEHIND your subject is right in the axis of maximum pickup for the mic just like the subject's voice and you lose any advantage to using a directional mic with respect to those sounds. That's why booms are used to place the mic aimed downwards from above and in-front of the subject, so the mic is pointed toward empty ground behind the subject and any sources of interfering noise will fall in the nulls of the pattern. There really are no magic settings that will nullify these fundamental physical realities.

Trevor Dennis · January 23rd, 2013, 08:18 PM

Get your subjects to hand hold the mic? If you need your own voice recorded as well, use a second lav attached to your self.

Les Wilson · January 24th, 2013, 08:12 AM

A dynamic mic such as an SM58 or E835 is better for this. I did interviews in a bus once. Either the talent or an assistant will need to hold the mic. You want to be within an inch off their mouth. Like an ice cream cone just before the lick. TIP: If you get one with a switch, gaff tape over it when filming the general population. I prefer the Sennheiser switch design over the Shure. YMMV

Trevor Dennis · January 24th, 2013, 02:59 PM

Quote:

Originally Posted by Les Wilson

A dynamic mic such as an SM58 or E835 is better for this. I did interviews in a bus once. Either the talent or an assistant will need to hold the mic. You want to be within an inch off their mouth. Like an ice cream cone just before the lick. TIP: If you get one with a switch, gaff tape over it when filming the general population. I prefer the Sennheiser switch design over the Shure. YMMV

Going off at a bit of a tangent here, but your comment about the tape reminded me of this demonstration of how much noise can be generated by wind blowing across switches and XLR connections.

This was new to me and rather surprising, but a point well taken.

John Nantz · January 24th, 2013, 07:45 PM

Trevor - great reminder! I remembering watching that video quite a while back but forgot a number of the details on the list.

I remembered about covering up the switches but forgot about the XLR connection. That one I'm kinda surprised about because you wouldn't think that part would make any difference but maybe there is some kind of open channel "conduit" inside the mic tube to the mic pickup? Maybe it's just the XLR connection on the mic but all the rest of them should be purely electrical connections and shouldn't matter.

As for tape, black electrical tape is smooth on the outside but the sticky part can be really really gooey. If the smoothness didn't matter I'd recommend 3M blue masking tape because it doesn't leave behind any sticky substance and can be left on for quite a long time without a problem. They say a week but I've had experience for way longer than that. But maybe the blue wouldn't look as professional???

Roughing up the fuzzy: Personally, I don't like touching it any more than I have to with my oily hands. The brush thingy is a much better solution. My Rycotes have a neat retractable comb/brush gizmo for that purpose.

Thanks for remembering the video and finding it.

January 21st, 2013, 10:08 PM	#1
Todd Shilkin Tourist Join Date: Jan 2013 Location: Perth, Western Australia Posts: 2	Capturing Good Audio in a Noisy Environment - Panasonic AC90 + Rode NTG1 Hi All, I've started a similar thread on the DVXUSERS forum, but figured that whilst there is obviously going to be some cross over of members, I may well get some different insights here, especially given the 'All Things Audio' Board. I'm a newbie with the AC90 being my first AVCCAM, and the Rode NTG1 being my first shotgun mic. I'm doing a fair bit of vox-pop style/ run and gun interviews in cafe/ restaurant environments, and I'm struggling to get good audio. What I've been finding is that all of the cooking and air con equipment means that there seems to always be an underlying 'hum' or background noise, as well as the clanking of pots and dishes etc. I was hoping that the ntg-1 would mean a more concise 'directional' recording, but I'm still finding the recordings are very noisy. Without an audio guy and a boom mic with me, are there things I could be doing/ basic settings I should always have, etc to get the best possible sound with the least amount of background noise? Also, should I always expect to have to some kind of NLE noise gate plugin manipulations, or should it possible to achieve good audio without the need to spend hours in post production? Thanks in advance for your help. Todd

January 21st, 2013, 10:23 PM	#2
Steve House Inner Circle Join Date: Mar 2005 Location: Hamilton, Ontario, Canada Posts: 5,742	Re: Capturing Good Audio in a Noisy Environment - Panasonic AC90 + Rode NTG1 Proximity is your friend. The closer you can get the mic to the subject the louder the voice will be in comparison to the surrounding noise. The optimum working distance for a short shotgun like your NTG-1 is about 18-22 inches. Secondly, if the axis of your directional mic is parallel to the axis of the lens, as it will be if the mic is mounted at the camera, any noise source BEHIND your subject is right in the axis of maximum pickup for the mic just like the subject's voice and you lose any advantage to using a directional mic with respect to those sounds. That's why booms are used to place the mic aimed downwards from above and in-front of the subject, so the mic is pointed toward empty ground behind the subject and any sources of interfering noise will fall in the nulls of the pattern. There really are no magic settings that will nullify these fundamental physical realities. __________________ Good news, Cousins! This week's chocolate ration is 15 grams!

January 23rd, 2013, 08:18 PM	#3
Trevor Dennis Major Player Join Date: Dec 2010 Location: New Zealand, Rapaura (near Blenheim) Posts: 434	Re: Capturing Good Audio in a Noisy Environment - Panasonic AC90 + Rode NTG1 Get your subjects to hand hold the mic? If you need your own voice recorded as well, use a second lav attached to your self. __________________ Stills at: www.flickr.com/photos/trevor-dennis/

January 24th, 2013, 08:12 AM	#4
Les Wilson Inner Circle Join Date: Jan 2004 Location: Boca Raton, FL Posts: 3,014	Re: Capturing Good Audio in a Noisy Environment - Panasonic AC90 + Rode NTG1 A dynamic mic such as an SM58 or E835 is better for this. I did interviews in a bus once. Either the talent or an assistant will need to hold the mic. You want to be within an inch off their mouth. Like an ice cream cone just before the lick. TIP: If you get one with a switch, gaff tape over it when filming the general population. I prefer the Sennheiser switch design over the Shure. YMMV

January 24th, 2013, 07:45 PM	#6
John Nantz Trustee Join Date: Jun 2010 Location: Seattle WA Posts: 1,254	Re: Capturing Good Audio in a Noisy Environment - Panasonic AC90 + Rode NTG1 Trevor - great reminder! I remembering watching that video quite a while back but forgot a number of the details on the list. I remembered about covering up the switches but forgot about the XLR connection. That one I'm kinda surprised about because you wouldn't think that part would make any difference but maybe there is some kind of open channel "conduit" inside the mic tube to the mic pickup? Maybe it's just the XLR connection on the mic but all the rest of them should be purely electrical connections and shouldn't matter. As for tape, black electrical tape is smooth on the outside but the sticky part can be really really gooey. If the smoothness didn't matter I'd recommend 3M blue masking tape because it doesn't leave behind any sticky substance and can be left on for quite a long time without a problem. They say a week but I've had experience for way longer than that. But maybe the blue wouldn't look as professional??? Roughing up the fuzzy: Personally, I don't like touching it any more than I have to with my oily hands. The brush thingy is a much better solution. My Rycotes have a neat retractable comb/brush gizmo for that purpose. Thanks for remembering the video and finding it.