Too Much Air Noise a Deal Breaker?

[Manchelli]

I'm editing my film and cannot get the air noise to go down without the audio being total shit. I'm not sure exactly how it's done in "The Biz" (that sounds pretty unprofessional, but oh well; I'm indie, right? Haha), so I don't know what exactly to do.

I shot with a boom and muff on the boom, now in post, should I adjust the levels so it's quiet when no one speaks, then the volume goes up when they speak, then down right after? I can still hear the air noise when that happens, so it's a bit distracting to me to hear ssssssSSSSHHHHHHTALKTALKTALKSSSHHHHsssssss if that makes any sense whatsoever (as you can tell, I'm typing this from the comfy cell of an asylum).

So, if there is quite a bit of background air noise (thought the speaking words, etc., are louder), is it a dealbreaker for festivals? Thanks!

LM

 

[gooberman]

im no expert but you try do voice over. or like you said cut out the parts where there is no talking. but i wouldnt just leave silence, replace it with so background noise like enviroment noise. birds and shit. your best bet would be to get good audio during recording instead of trying to correct it in post.

 

[gpforet]

I'm not sure what you mean by "air noise". Is it air conditioning, outdoor wind?

If it's outdoor wind noise, how it's done in "the biz" is a blimp, with windjammer. I recently boomed on location in coastal florida outdoors with wind going about 20 mph and it's amazing what a blimp and windjammer will do. It is twice as effective as a "muff" or "softie".

If your problem is with an indoor shot and it's air conditioning noise, we turn off all air conditioning and air handling during the shoot.

But, since it sounds like re-shooting is not an option for you, if the noise is constant, you may be able to notch it out with a parametric eq and still preserve usable dialog.

I'm sure others will chime in with additional post tricks which may save you.

I'm editing my film and cannot get the air noise to go down without the audio being total shit. I'm not sure exactly how it's done in "The Biz" (that sounds pretty unprofessional, but oh well; I'm indie, right? Haha), so I don't know what exactly to do.

I shot with a boom and muff on the boom, now in post, should I adjust the levels so it's quiet when no one speaks, then the volume goes up when they speak, then down right after? I can still hear the air noise when that happens, so it's a bit distracting to me to hear ssssssSSSSHHHHHHTALKTALKTALKSSSHHHHsssssss if that makes any sense whatsoever (as you can tell, I'm typing this from the comfy cell of an asylum).

So, if there is quite a bit of background air noise (thought the speaking words, etc., are louder), is it a dealbreaker for festivals? Thanks!

LM

 

[Manchelli]

I'm not sure what you mean by "air noise". Is it air conditioning, outdoor wind?

If it's outdoor wind noise, how it's done in "the biz" is a blimp, with windjammer. I recently boomed on location in coastal florida outdoors with wind going about 20 mph and it's amazing what a blimp and windjammer will do. It is twice as effective as a "muff" or "softie".

If your problem is with an indoor shot and it's air conditioning noise, we turn off all air conditioning and air handling during the shoot.

But, since it sounds like re-shooting is not an option for you, if the noise is constant, you may be able to notch it out with a parametric eq and still preserve usable dialog.

I'm sure others will chime in with additional post tricks which may save you.

What I mean by "air noise" is just the general noise in the background. It's not necessarily the people in the background, but just the constant SHHHHH noise. Not static, but air. Not sure how else I can say it. My boom muff isn't great, so I'll have to get a new one.

What mic covering should I use for inside, what one for outside?

Thanks.

 

[gpforet]

Unless air is moving it really doesn't make noise.

It sounds like you are describing mic self-noise or preamp noise. This is typically constant and unchanging and cannot be overcome by any kind of wind protection. It is usually an indication of either very inferior preamps or improper gain staging.

Did you have to normalize the recording or really have to crank up the audio levels in editing? Again, you may be able to salvage it by using a parametric and sweep until you find where the hiss resides. I'm guessing somewhere around 4k to 8k. Once you have the frequency you can apply a cut and narrow the parametric slope until the hiss starts coming back in. Sweep and ajust slope until you are satisfied. It is going to suck out alot of life from the dialog.

Perhaps you can post a small segment so we can hear what you are describing.

As far as what covering to use on the boom:

Outdoors in low wind I'll typically just use the blimp without windjammer. If that won't cut it, I'll add the windjammer.

Indoors, I use a softie which helps cut wind noise when swinging the boom.

What I mean by "air noise" is just the general noise in the background. It's not necessarily the people in the background, but just the constant SHHHHH noise. Not static, but air. Not sure how else I can say it. My boom muff isn't great, so I'll have to get a new one.

What mic covering should I use for inside, what one for outside?

Thanks.

 

[Alcove Audio]

How about a few more details about how the audio was recorded, such as which mic was on the end of the boom, what was the recording medium (camera, DAT, etc.), bit/sample rate and other such information, like who swung the boom, set up and monitored the audio, etc.

And you could post a sample of the audio - no picture required.

The first mistake most newbs make is not disabling the Automatic Gain Controls (AGC) on the camera. AGC almost automatically will raise the noise between the lines and will sometimes make the noise just as loud as the dialog while the talent is speaking.

Another mistake is not understanding gain-staging and signal flow. Improper gain-staging leads to lots of hiss and other self noise from the gear if signal levels are set too low, and distortion if set too high.

Dialog editing and noise reduction are complex subjects and cannot be covered comprehensively in a forum post. Two very simple things to give you a start. Select the Low Pass Filter of your parametric EQ and, starting at 12k, slowly lower the frequency until the hiss is reduced; you'll have to find a compromise/balance between reducing hiss and "dulling" the dialog. Next you use the volume automation to lower the volume between lines of dialog. Again, it's a balance between reducing unwanted noise and making the dialog sound artificial.

 

[2001 Productions]

The first mistake most newbs make is not disabling the Automatic Gain Controls (AGC) on the camera. AGC almost automatically will raise the noise between the lines and will sometimes make the noise just as loud as the dialog while the talent is speaking.

This is interesting, Alcove. I've never heard of an AGC for audio. Is that only on low-level consumer cameras? Mine has an AGC for video and an ALC for audio. Is that what you're referring to?

Because I had nobody to mix on set - only a boom op - I (sheepishly) admit I recorded dialog for my current project using the ALC, but in post I'm removing all sound between each line anyway, adjusting levels and filtering noise, then layering in tone, effects and ambiance. It may be unorthodox but it sounds great, certainly no more noisy than if I'd adjusted levels manually, and nothing exceeds 0db.

Mine is a fairly decent camera (XH-A1) so maybe some have better ALC circuitry than others.

 

[gpforet]

The ALC is a limiter. Not the same as AGC. A current project I'm working I have audio run to the camera (Panasonic 170) and we leave ALC enabled but I'm limiting before my audio gets to the camera so I'm never hitting the camera limiters.

This is interesting, Alcove. I've never heard of an AGC for audio. Is that only on low-level consumer cameras? Mine has an AGC for video and an ALC for audio. Is that what you're referring to?

Because I had nobody to mix on set - only a boom op - I (sheepishly) admit I recorded dialog for my current project using the ALC, but in post I'm removing all sound between each line anyway, adjusting levels and filtering noise, then layering in tone, effects and ambiance. It may be unorthodox but it sounds great, certainly no more noisy than if I'd adjusted levels manually, and nothing exceeds 0db.

Mine is a fairly decent camera (XH-A1) so maybe some have better ALC circuitry than others.

 

[knightly]

The XHA1 has auto and Manual controls for the audio, set it to manual... the description is indeed the AGC/ auto volume stuff. immediately, you can counter most of what the AGC did by dropping the volume between the talking to have the air held at bay (transitions from silence to talking will still be a bit wonky though).

What it does is give you a really strong signal to sample for noise reduction

 

[Alcove Audio]

ALC - Automatic Limiting Control. A limiter puts a hard ceiling on the audio levels. ALC can be a useful tool as long as it is used judiciously. If pushed too hard can cause distortion or, with long-term high-volume, can cause "pumping".

AGC - Automatic Gain Control. A compressor also puts a ceiling on the audio levels and but at the same time raises the floor on the low volume sound sources; a whisper becomes as loud as a scream. That means that ALL sound, including any and all background noise plus the self-noise from mics and mixers becomes artificially raised. This is much harder to correct as the background noise is almost instantaneously brought up to the level of the loudest sounds making editing and/or volume automation to remove the noise between lines of dialog very difficult to do. AGC is for vidiots - consumers and those who just don't give a crap about or pay attention to audio. AGC is a huge no-no for any serious filmmaker; it should be completely disabled if at all possible

Standard production sound/dialog editing is basically as 2001 pointed out. You checkerboard the dialog, strip out the sound between lines of dialog and add room tone &/or other ambience. Noise reduction is applied and EQ (& sometimes reverb) is used to match the disparate lines of dialog (usually during the mix). Then you replace all human made sounds with Foley and sound FX as you have now stripped all of that out in the dialog editing process.

 

[Utopia]

The thing I don't like about editing dialogue is it's a thankless job.

You could be the genius of all geniuses and no-one would be the wiser. They only hear the finished track.

 

[Alcove Audio]

The thing I don't like about editing dialogue is it's a thankless job. You could be the genius of all geniuses and no-one would be the wiser. They only hear the finished track.

But all filmmaking is - or at least should be - exactly that.

Filmmaking is the art of the invisible; if anyone notices your work you haven't done your job right.

In other words anything that pulls you out of the experience is a mistake.

Besides, the thank you's come in the form of large checks and repeat clients. But most of all the reward comes from the personal satisfaction of knowing that you did a great job and earning the respect of your peers.

 

[Utopia]

I'd like to see more audio editors headlining in the tabloids for scandals and such.

j/k

I agree with you wholeheartedly, Alcove. I'm just saying that you could do the best edit ever and no-one would notice. Like how I had to create a sentence out of a character in an audiobook who didn't originally say it at all - I had to piece it together from other words he said - and no-one noticed and acted like he had recorded it all along.

 

[2001 Productions]

Thanks for the AGC/ALC clarification, guys.

Knightly, I did use the auto setting on the A1, but it certainly did not amplify the BG noise to any kind of absurd level. There is no change in noise level going from dialog to silence, so it must have some kind of AI or something that prevents that(???).

I had to create a sentence out of a character in an audiobook who didn't originally say it at all - I had to piece it together from other words he said - and no-one noticed and acted like he had recorded it all along.

Yep, I do this kind of thing all the time. Also do a lot of sync'ing of take 1 audio (better delivery) with take 2 video (better performance).

I apprenticed under a pro film editor whose mantra was, "Performance dictates the cut." I've since adopted it as my own.

 

[Alcove Audio]

Also do a lot of sync'ing of take 1 audio (better delivery) with take 2 video (better performance).

I've re-cut the dialog of entire scenes using the dialog from the unused takes. Thank God for Vocalign!

 

[Utopia]

If only kids today knew what people went through in the good ol' days...

hehe.

(my mixboard is 10 years older than I am).

 

[wheatgrinder]

FWIW: My canon hfs100 had a Auto Gain Circuit in audio. It does HORRIBLE things.. with the off camera mics.. but with the on camera mic, seems to work well. My guess its very purposefully designed to get the best sound from the camera mics..

 

[Utopia]

All it's for is for the moments at family reunions when Uncle Henry is mumbling in a corner of a party room and you've got the camera on him from across the room - the auto-gain makes it possible for you to hear him.

Auto-gain should never be used on semi-professional/professional projects.

!!!

 

[2001 Productions]

My canon hfs100 had a Auto Gain Circuit in audio. It does HORRIBLE things.. with the off camera mics..

That's why I wonder if the XH-A1 has some kind of special circuitry. I used a Senny M66 with phantom fed direct into my camera and the quality was very good, IMO.

You've heard the raw, unsweetened tracks wheat. How did they sound to you?

The other possibility is that it was always pegged at full volume anyway because my actors were speaking with normal voices - i.e. not projecting - so using auto was basically just acting as an ALC...

 

[wheatgrinder]

2001s tracks sound great. Yeah, I think your camera is pro, and such has true pro implementations of what could be a useful feature. My consumer cam has a different market to say the least..