audio rumble noise with Sony HXR-NX30U

J

joker454

Well-known member
I've been having issues over the years using external mic's on cameras, always with excess noise captured by the mic. I've returned many mics/cameras over the years because of this so this time instead I tried ordering an all in one figuring that would work better, which is the Sony HXR-NX30U. I received it yesterday, I figured since they included a mic that it's all designed to work together well and I'd get no noise. Alas I'm still hearing noise, so at this point I figure it must be me but I just can't figure out for the life of me how to get clean audio from this thing.

For tripod or documentary type purpose where the camera doesn't move, the mic is fine. But most of my filming is random run and gun, so
I'm holding the camera and moving around. In this situation I'm constantly hearing some kind of low frequency rumbling noise. I've tried holding the camera by it's handle while recording, and using a rig I have but I still hear that noise. I put a short recording of it here at this link:

http://www.realitystudiollc.com/audioissue.mp4

Video quality is low to make the file small, but you can hear the issue in the audio. There was no wind at all, that rumbling you hear just seems to be coming from, well, I don't really know where. Even when I film indoors it's the same, anytime the camera is moved you hear that rumbling noise which makes it totally useless for my purposes. I tried setting "low cut" on the mic but that didn't solve it, tried manual mic levels and that didn't work either. How do you guys get clean audio from external mics? I've always just used the internal camera mics because after trying countless external mics I just could never get noise free audio so I gave up, but I figure there must be a way. The stuff I film is like reality shows basically, so one camera moving around and no separate audio guy holding a boom mike, it all must be self contained on the video gear which is why I was
hoping the NX30U would finally solve my issue but it didn't. Anyways I'm going to keep playing with the camera, but I'm grateful for any suggestions!
 
Hi, I tried a high pass filter but even set at 200hz the rumble, albeit reduced, was still there as a more tinny sounding artifact. Male voices also got dramatically effected by that for the worse. Setting it down to 80hz or so didn't effectively remove the rumble. The mic itself has a "Low Cut" setting which I set to on, but it doesn't remove the rumble noise, that test video I posted was recorded with Low Cut on.
 
Can you post a pic of how the mic is mounted as it doesn't sound right to me.

The mic that comes with most sony cameras is quite reasonable these days and if its the same as the one that came with my Z7 is very similar to the AT875R.

Are you aware that the capsule is towards the rear of the mic so if you have mounted it further forward the clamp may be covering the capsule and picking up more noise.
 
I think you have unrealistic expectations of:
1) what raw production audio should sound like, and
2) the capabilities of ANY microphone to produce clean audio at unrealistic distances or under unrealistic ambient noise situations.

The kind of sound you hear in a finished TV show or commercial movie was NOT produced by ANY kind of microphone mounted on a camera. Camera-mounted (or internal) microphones seem popular because it is easy for the manufacturer to appear to deliver a "complete" solution for recording picture and sound. But they also produce the extremely unrealistic expectation that you can actually get usable, decent sound tracks from a camera-located microphone. IME the situations where you can get good quality sound track from a camera-located microphone is well under 5% of the cases. And that is probably generous.
 
+1 on what Richard said

Also it sounds like there is NO wind protection or any type of shock protection on the mic, so you are almost guaranteed to get these low end artifacts.

look at B&H for wind and shock mount options for your mic, they ussualy have packages for most mics available that will help curtail this low end rumble.

it also sounds like the gain is either on AGC (Auto Gain Compensation) or is just too high. you can hear the lens focusing.

also keep in mind that no matter how fancy or expensive a mic is or how inconvenient it is the camera is still and will ALWAYS be the WORST place for a microphone. (this part is just physics)
 
GaryNattrass said:
Can you post a pic of how the mic is mounted as it doesn't sound right to me.

The mic that comes with most sony cameras is quite reasonable these days and if its the same as the one that came with my Z7 is very similar to the AT875R.

Are you aware that the capsule is towards the rear of the mic so if you have mounted it further forward the clamp may be covering the capsule and picking up more noise.
Click to expand...

Here's a few pics I just took:

http://realitystudiollc.com/images/nx30/1.jpg
http://realitystudiollc.com/images/nx30/2.jpg
http://realitystudiollc.com/images/nx30/3.jpg
http://realitystudiollc.com/images/nx30/4.jpg
http://realitystudiollc.com/images/nx30/5.jpg

The way the mic is one this camera there is really only one way to mount it, theres a concave part of the back of the mic that has to go into the holder and it just fits. I double checked in the instructions and it's what it says as well. It also mentions that the mic name should be face up so I did that too.


Richard Crowley said:
I think you have unrealistic expectations of:
1) what raw production audio should sound like, and
2) the capabilities of ANY microphone to produce clean audio at unrealistic distances or under unrealistic ambient noise situations.

The kind of sound you hear in a finished TV show or commercial movie was NOT produced by ANY kind of microphone mounted on a camera. Camera-mounted (or internal) microphones seem popular because it is easy for the manufacturer to appear to deliver a "complete" solution for recording picture and sound. But they also produce the extremely unrealistic expectation that you can actually get usable, decent sound tracks from a camera-located microphone. IME the situations where you can get good quality sound track from a camera-located microphone is well under 5% of the cases. And that is probably generous.
Click to expand...

I was wondering about that, I'm relatively new to the audio side of things so perhaps I have uinrealistic expectations. What I need is basically like on tv reality shows, stuff like Swamp People, Storage Wars, etc. On those types of shows there isn't a separate audio guy holding a boom mic, etc, it's basically one guy with one camera with the one person he is filming and that's it correct? Often there's just no room for anyone else, even on shows like Dirty Jobs when the camera guy puts himself in tight spaces with the shows host.

Here's an example, once on Storage Wars the camera guy was filming Dave Hester while in the car, it was a two seater car so it was just Dave and the camera guy. As Dave stopped and got out of the car he dropped an item and broke it. The camera guy in the passenger seat, being he was the only person there filming, got out quickly, ran out over to the drivers side of the car and basically didn't miss a beat, he filmed the whole thing by hilmself with that one camera and the audio was great. You could see his fingers briefly in front of the lense as he was running out I think because he slapped on a filter when he got out of the car as the video was overexposed briefly once he got out, but that's about it. His audio wasn't filled with noise it actually sounded good. That's the kind of stuff I need the camera for, one person, one camera, unscripted scenarios where anything can happen. Is it possible I just need far more expensive gear to get good audio with that, and that my little NX30 is really just meant to be on a tripod when using it's external mic? I got all excited when I saw the NX30 because it looked like exactly what I needed, really good stability control is hugely important to me because of the unscripted nature of what I film, and with that standard external mic I thought I was all set! But I'm starting to wonder if that external mic is really only intended to be used while the camera is mounted on a tripod, and the internal mic should be used when using it run & gun.
 
Last edited:
recordingwhiz said:
+1 on what Richard said

Also it sounds like there is NO wind protection or any type of shock protection on the mic, so you are almost guaranteed to get these low end artifacts.

look at B&H for wind and shock mount options for your mic, they ussualy have packages for most mics available that will help curtail this low end rumble.

it also sounds like the gain is either on AGC (Auto Gain Compensation) or is just too high. you can hear the lens focusing.

also keep in mind that no matter how fancy or expensive a mic is or how inconvenient it is the camera is still and will ALWAYS be the WORST place for a microphone. (this part is just physics)
Click to expand...

I don't think it was wind as it does it even when filming indoors, and it does it even when auto focus is turned off. I'll look into shock mounts, didn't know about those. Yeah I figured it's not the ideal place to have the mic but for what I film there isn't much choice, imagine TMZ style stuff where one guy is doing it all, walking and filming, etc, it needs to be a small self contained movie studio basically that can also fit into small places if need be. I figure these reality shows do it so there has to be a way, but I'm fearing that it might mean using very expensive gear is the only way to do :(

EDIT: A added a closer pic of the mic mount on my nx30:

http://realitystudiollc.com/images/nx30/6.jpg

Those 8 round things are rubber and they press against the mic tightly to hold it in place. Could that be the issue, where any touch on my camera rig is getting transfered to the mic via those 8 rubber feet? I also added this pic:

http://realitystudiollc.com/images/nx30/7.jpg

I'm using a scorpion handle, slightly modded to work with this camera. I can't use the handle on the nx30 itself, that just makes the audio unusable with all kinds of noise. Using the scorpion handle helps dramatically, but I just have that rumble remaining. I tried added felt between the camera and the scorpion mount to maybe isolate it more from noise but that didn't work.
 
Last edited:
that is Son'y attemt at shock mounting but its trivial at best.

On shows like the ones you mention you bet your bottom there is a sound guy or 2 or 3, I will bet my life on it. when you see one camera in a 2 seater car that means that Dave H has been wired up with a wireless lavalier microphone and either the sound guy is capturing audio in a near by van or the camera has a camera mount receiver. SHows that have a budget would NEVER consider NOT having a sound guy as they know that the best video without audio = trash, and that is wasted money. you dont see an audio guy simply because he is the easiest to have out of the camera frame. if you look closer on some of these shows youll see every principal character wearing a belt pack of some sort, I know I have seen the wife of that younger couple wearing it on her belt at least a few times.
Keep in mind that true pro sound guys are experts at hiding the mics. dont make the mistake and assume they are not there.
the servo noise I hear my be some part of the lens still in 'auto' mode, perhaps the ND filter or iris. but that noise deff came from a servo motor on the camera of some sort.

look around youtube for some BTS stuff and sure enough youll see a guy with headphones and a boom on all of these shows. and more than likely a guy sitting at a cart with a mixer and wireless receivers as well.

Guys with budget and experience do Not risk bad audio for sakes of convenience.

just my 2 cents.

good luck
 
Also another observation I just made when I took another look at your settings, you have AGC enabled (Auto) as well as have the gain all the way up. both of these are considered no-no's for good quality audio, that is probably why you are picking up every little bump and noise. and BTW yes moving a camera indoors does move air around the microphone just like outdoors. but with proper settings your foam should suffice for the moment.

try turning the AUTO off and lowering your levels, try starting at 5 (that is the reason why the 5 is highlighted on your knob) rather than 10 , then see how the meters read with some one speaking at the distance you will be using. Im assuming the camera has meter? if it does try to get dialog to average around -12 to give yourself some headroom or even -20 if there is a possibility that things might get loud. and by all means monitor the audio, Im also assuming the camera has a headphone output as well. you can always raise the level up in your editing software, but make sure your recording isnt too low as it will also record its self noise.

Good audio is like surfing, you have to maintain a good enough level to where you dont distort and not too low that you have to raise the noise floor up along with the audio to get a decent level. Read the stickies in this portion of the forum, its filled with TONS of great information from a lot of great guys that do this professionally are are here to help.
there is also a DVD I believe available with the information you seek.

Audio is a craft all on its own and it requires as much care and respect as the cinematography, and usualy more gear. there is a great saying in film making "Audiences will forgive bad video but they wont forgive bad audio" and most start up film makers learn this the hard way, heck, most of this forum is filled with guys asking what went wrong on their film after they assumed that the built in mic on the camera was gonna be good enough.

also keep in mind that there is NOTHING auto about audio, you will have to change this setting depending on every situation.

hope this helps a bit.
 
Thanks for all the info, it does help a lot. I guess it makes sense that people are wired with wireless mic's on reality shows. I'm a bit of a noob on the audio side of things so I'm still sorting it all out. The levels were at max because I was doing some tests actually, I tried making recordings with auto on, and auto off at various levels, my last test was at level 10 hence why those controls are at that level. I'm pretty sure right now that the issue is because the mic just isn't isolated enough and it's picking up any touch. I did a test someone had recommended, I left the camera on a table, plugged in some headphones, turned it on and just listened to it while i touched the camera at various spots. Turns out I can hear every single touch, even softly touching the rig part, it will be picked up by the mic, that's in auto, low gain, etc. So it seems like the stock mic holder just doesn't isolate the mic enough from any touch alas. Maybe I do need a shock mount as someone in this thread suggested, or a better rig than my cheapo one. Anyways, I think what I'll do for now is use the built in internal mic for my run and gun reality stuff since it's so unpredictable, and use the external mic for all the rest which is tripod recordings so I can determine best levels to use for that stuff much easier. I did a bunch of tests today and when recording via tripod the external mic's sound quality is so much better than the internal mic that it's almost comical to compare, so it'll still get lots of use. In the meantime I can look into better rigs or shock mounts and see if I can make that external mic useable one day for my reality stuff. I guess lesson learned here, I fell for the marketting pics which show these cameras being used with the on camera external mic and actually thought that would easily work :( Thanks for the help guys!
 
I appreciate what all the other guys are saying re getting good sound from a camera mic but you should be able to use it to get general effects etc.

The mic mount looks fine to me and identical to the one that was fitted to my Z7 and S270 cameras which would also probably use the same mic.

Yes AGC can cause problems but I have to say I run my panasonic P2 cameras in auto quite a lot of the time as I have confidence in the gain circuits and always monitor what I am doing, you should be able to get a noise and rumble free sound out of any camera and I use my HPX371 camera mic all the time as a general ambient effects source or in emergencies on news to grab speech recordings if I can get within two feet of the subject and don;t get that sort of handling noise with a similar type mic.

I don't think you should be getting that amount of mic handling noise and I seem to recall my Z7 had a two stage filter system, one for wing and the other for noise reduction that seemed to get rid of buzzes and other noises caused by LCD screens etc.

Camera mic's are no substitute for a sep mic set-up that can get nearer to the source but they should be still useable in certain situations.
 
Last edited:
OK here is an example of a shot I did last summer during a film school.

http://www.youtube.com/watch?v=xc1oCvpdX34&feature=youtu.be

The main production sound was taken from the AT875R with G2 radio transmitter the girl is holding but I uploaded just the camera mic for you to listen to as I was moving the camera around quite a bit.

As you can hear even with the auto gain circuits on and the high pass filter at 80hz I am not getting too much rumble or handling noise.

This is a chinese shotgun mic I got on e-bay for $75 and it is similar to the ones that are provided with cameras, it is marked as a panasonic AJ -MC700P but we suspect these are copies of the original mic, still picks up half decent sound though and here is another example of it in use at a UEFA soccer match: http://www.youtube.com/watch?v=66oTdtBrAxE

As previously stated by several posters a camera mic is not a one stop shop for production sound but you should not be getting that type of LF rumble with it under normal use.

Even this behind the scenes footage that I grabbed run and gun with a small canon HF11 using its in built mic has some useable audio without the type of rumble you are experiencing: http://www.youtube.com/watch?v=CC94y16hxSU
 
Last edited:
joker454 said:
He...

I was wondering about that, I'm relatively new to the audio side of things so perhaps I have uinrealistic expectations. What I need is basically like on tv reality shows, stuff like Swamp People, Storage Wars, etc. On those types of shows there isn't a separate audio guy holding a boom mic, etc, it's basically one guy with one camera with the one person he is filming and that's it correct? Often there's just no room for anyone else, even on shows like Dirty Jobs when the camera guy puts himself in tight spaces with the shows host.
....
Click to expand...

What on Earth makes you believe these shows are shot by one-man-bands? The typical reality show is shot by two or three man field teams. Shows like Cops, Storage Wars, etc generally put lavs on the principle characters feeding receivers carried by a sound person in an audio bag along with a mixer and proper field recorder around his neck.
 
GaryNattrass said:
OK here is an example of a shot I did last summer during a film school.

http://www.youtube.com/watch?v=xc1oCvpdX34&feature=youtu.be

The main production sound was taken from the AT875R with G2 radio transmitter the girl is holding but I uploaded just the camera mic for you to listen to as I was moving the camera around quite a bit.

As you can hear even with the auto gain circuits on and the high pass filter at 80hz I am not getting too much rumble or handling noise.

This is a chinese shotgun mic I got on e-bay for $75 and it is similar to the ones that are provided with cameras, it is marked as a panasonic AJ -MC700P but we suspect these are copies of the original mic, still picks up half decent sound though and here is another example of it in use at a UEFA soccer match: http://www.youtube.com/watch?v=66oTdtBrAxE

As previously stated by several posters a camera mic is not a one stop shop for production sound but you should not be getting that type of LF rumble with it under normal use.

Even this behind the scenes footage that I grabbed run and gun with a small canon HF11 using its in built mic has some useable audio without the type of rumble you are experiencing: http://www.youtube.com/watch?v=CC94y16hxSU
Click to expand...

Thanks for uploding those, so if I understand you right the 1st and 3rd videos are internal camera mic audio, and the 2nd video is with an external camera mounted shotgun mic audio correct? I don't actually get any rumble when using the camera's internal mic, it actually works fine although the sound quality is that of a built in mic. I only get the rumble when using the provided camera mounted shotgun mic. Your second video doesn't have that rumble, although maybe it because it's a pretty noisy video in general being a soccer match so it may be hard to hear it anyways, plus the camera doesn't move too much on it. I've been doing more tests today, this time not using my rig but just holding the camera in hand like on the marketting shots and I'm still having a bear of a time not getting any rumble noise irregardles of audio settings. Part of the issue is that when holding the camera as shown in the marketting pictures means your pinky finger rests on the little nubbin that plugs into the active shoe to provide phantom power to the mic, so even the slightest movement of that finger means audio noise. I tried filming a segment where I locked all my fingers into the air not touching the camera which helped, but was too painful to realistically film with. I did though finally manage to get a rumble free recording by trying something silly. I didn't hold the camera at all, instead I suspended it via a short rope and walked around with it like that, recording my entire backyard. There was almost no noise on that recording, so that tells me that the whole unit is indeed just extremely sensitive to any finger movement. I think for the type of use that I want, which is lots of camera movement like moving it up and down pointing it in the air, etc, I'll just have to find either a much better shock mount, or a custom rig that really isolates me from the camera.


Steve House said:
What on Earth makes you believe these shows are shot by one-man-bands? The typical reality show is shot by two or three man field teams. Shows like Cops, Storage Wars, etc generally put lavs on the principle characters feeding receivers carried by a sound person in an audio bag along with a mixer and proper field recorder around his neck.
Click to expand...

Well it's just from what you see sometimes on various shows. Like on Deadliest Catch sometimes they show the entire boat they are filming from a camera boat beside it so you can see the entire deck, and there's not a sound guy to be found, all you see is two guys holding their weather protected cameras at opposite ends of the boat, no other crew on the entire deck of the boat. Also how do they wire those crabbers with audio when they are wearing a raincoat wrapped tightly around their head, and if they are wired for sound why do the camera guys still leave the external camera mouned mic on their camera if they aren't using it, especially given the already harsh conditions they are working in? I figure if they weren't using that camera mounted mic at all then just remove it and save some weight.
 
joker454 said:
T...
Well it's just from what you see sometimes on various shows. Like on Deadliest Catch sometimes they show the entire boat they are filming from a camera boat beside it so you can see the entire deck, and there's not a sound guy to be found, all you see is two guys holding their weather protected cameras at opposite ends of the boat, no other crew on the entire deck of the boat. Also how do they wire those crabbers with audio when they are wearing a raincoat wrapped tightly around their head, and if they are wired for sound why do the camera guys still leave the external camera mouned mic on their camera if they aren't using it, especially given the already harsh conditions they are working in? I figure if they weren't using that camera mounted mic at all then just remove it and save some weight.
Click to expand...
I kinow Deadliest Catch uses sound people because I recall reading a thread on either Gearsluts or Jeff Wexler's site forum a couple of year or so ago where the principle mixer for the show was one of the participants. They do indeed wire the crew with wireless - Lectrosonics MM400 water resistant miniature beltpack transmitters, UM250C transmitters, and UCR411a compact receivers - with the receivers and recorders located in the cabin. Here a link to a site with an interview with the show's producer - http://www.prosoundweb.com/article/lectrosonics_braves_the_seas_on_discoverys_deadliest_catch/ - where he talks about it. As to why the camera ops leave the external mics on their camera, I have no idea. All they would ever be used for is ambiance, if that. The production company considers the cameras essentially to be disposable - the harsh conditions means they go through cameras like the Navy goes through coffee - so perhaps the mics that come packaged with the camera are equally considered to be disposable.
 
Ah ok, interesting, it didn't even occur to me to use on camera mic audio as ambience, then mix it with the wireless audio for vocals. Well thanks again for all the info guys, looks like I have much to learn on the audio side. It makes the video part seem easy in comparison!
 
recordingwhiz said:
try turning the AUTO off and lowering your levels, try starting at 5 (that is the reason why the 5 is highlighted on your knob) rather than 10 , then see how the meters read with some one speaking at the distance you will be using. Im assuming the camera has meter? if it does try to get dialog to average around -12 to give yourself some headroom or even -20 if there is a possibility that things might get loud. and by all means monitor the audio,
Click to expand...

Hey I wanted to ask you something about the above. I took a look at the audio levels in Vegas Pro, with the NV30's shotgun mic set at auto it averages around -11.9 in a test conversation which jives with your numbers so that's cool, using manual mic level 5 is similar although it doesn't auto compensate if the person moves closer to the mic. I tested the built in internal camera mic as well, its "Normal" level averages at -1.9 on the same type of test clip. Setting the internal mic to "Low" puts the average at -10.8 which is closer to your recommended numbers but oddly in the manual for the camera it does not recommend the "Low" setting on the internal built in mic for dialog. Do you think it's best to ignore what the manual says there as maybe it's just a general case recommendation? I did the same test with my older 560v camera and it's internal built in mic also averages around -1.9 at default settings so it seems like an intentional general purpose setting.
 
joker454 said:
Hey I wanted to ask you something about the above. I took a look at the audio levels in Vegas Pro, with the NV30's shotgun mic set at auto it averages around -11.9 in a test conversation which jives with your numbers so that's cool, using manual mic level 5 is similar although it doesn't auto compensate if the person moves closer to the mic. I tested the built in internal camera mic as well, its "Normal" level averages at -1.9 on the same type of test clip. Setting the internal mic to "Low" puts the average at -10.8 which is closer to your recommended numbers but oddly in the manual for the camera it does not recommend the "Low" setting on the internal built in mic for dialog. Do you think it's best to ignore what the manual says there as maybe it's just a general case recommendation? I did the same test with my older 560v camera and it's internal built in mic also averages around -1.9 at default settings so it seems like an intentional general purpose setting.
Click to expand...
The problem with auto level is that when the speaker pauses, the auto gain control ramps up the gain to max 'looking' for a non-existent signal. This means it's recording all the background noises as loud as it can get them, thinking they are the intended signal. Then when the speaker starts to talk once again, he comes in very hot until the gain control has time to turn itself back down again.
 
You must log in or register to reply here.
Back
Top