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Revisiting: sound cancelling headphones for monitoring recording

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Tom Galli
Revisiting: sound cancelling headphones for monitoring recording
on Jan 12, 2020 at 9:00:51 pm

Aloha all!

I know, the dogma is "sound-cancelling headphones color sound, and as such, are evil." I am questioning the dogma, though, and my last shoot reminds me why. We were outdoors. It was intermittently quite windy. And, there was a generator.

I wear full-coverage headphones (Senal SMH-1000 that day), which do provide some isolation from environmental sound, but only some. I seriously doubt it's 20dB, but I can't find a published number. Regardless, with the headphones over my ears, I could still hear the generator. But because I was hearing it, I couldn't tell if I was getting it on the body mics that were another 30 yards away.

Just for giggles, I even put a pair of hearing-protection earmuffs on. That's 32 dB of isolation, if the packaging is to be believed. I could still hear the generator in the distance. It wasn't loud, but if I listened for it, it was there. So, even if my monitor headphones had that kind of isolation, I'd still question "am I hearing it in the recording, or just as leakage through my headphones?"

It's beginning to seem to me that sound-cancelling technology could remove that doubt. A little inaccuracy in the frequency response might be a small price to pay in order to be sure that the signal is clean.

Anyone have thoughts on the matter?

Mahalo,
Tom G

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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Ty Ford
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 13, 2020 at 3:37:03 am
Last Edited By Ty Ford on Jan 13, 2020 at 3:43:30 am

Hello Tom and welcome to the Cow Audio Forum.

Big answer: Don't do it.

Little answer: Get a DNS-2 instead.

https://tyfordaudiovideo.blogspot.com/2016/08/the-cedar-dns-2-portable-dial...

With the noise coming from a nearby generator, I'd say you don't have a noise problem. You have a location problem.

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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David Peterson
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 14, 2020 at 10:52:17 pm

Active Noise Cancelling headphones are a HORRIBLE idea.

I feel your pain though when it comes to generators:






Did they do the absolute MAXIMUM they could to deal with the generator? First of all, hire it from a proper film rental house (as they'll stock quieter generators), not from a building/construction/etc rental house. Second, position the generator as FAR AWAY AS YOU CAN (see my video, it was waaay up a hill and down the other side by the road, and even though I wish was much further away). Third, what angle is the generator pointing? Often one side of it will be louder, and spinning the generator around 180 degrees makes a noticeable difference. Fourth, can you position anything between you & the generator? Putting a generator on the other side of a low stone wall might only be moving it by a few feet further away, but can make a bigger difference to the sound than the distance might suggest!

What you need (well, other than first you need to be dealt a better hand! These are not so much sound problems, as a location or electrical problem) is Remote Audio HN-7506

https://remoteaudio.com/products/hearing/high-noise-headset/

They're much much cheaper than a Cedar DNS2 (although I love this too! I own a DNS2 myself, but you could just leave it to be handled during sound post. Which is where it is meant to be), and HN-7056 addresses directly the problem of being able to monitor what's being recorded vs the DNS2 which just tries to hide/"fix" the problem. (although, get a DNS2 as well if you can, it truly is magical! But this is very much a luxury purchase)


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Tom Galli
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 15, 2020 at 12:22:12 am

It's funny to me how the replies are focusing on the generator. That was only the example from my most recent shoot, but it seems to be that, by its very nature, location recording means dealing with noise. Every time I've been in charge of recording audio on location, and sometimes even on a sound stage, at some point I have asked myself "am I hearing that as part of the signal, or am I hearing it because the sound is penetrating my headphones?" Clearly spending $3k on a filter for the mic will not change that question at all.

I do like the headphones you listed, and may well pick up a pair. Are they comfy enough to wear for a full day? They look like what I wear when I go shooting (the other kind), and those are definitely not comfortable enough for extended use.

What makes you say that noise cancellation is a "horrible" idea? This is the idea I'm interested in discussing. I get that there's concern about the sound-cancellation circuitry inadvertently coloring the sound, but when the quest is for clear sound, is a little false color really a sin? It's not as if I'm EQing in the field.

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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David Peterson
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 15, 2020 at 1:38:45 am

They're not as comfy as the MDR-7056 they're based on, as they do seal quite firmly around your head. (or maybe I just have a big head!) But yes, people do use these all day long. You'll see a pair of these being used on many pro sound mixers' carts.

If you ever get a chance to try out the Cedar DNS2 then do give it a go, the results will simply astonish you. Cedar has taken their very expensive high end big rack mount units and squeezed it all into a super small portable unit. I've used it often in my bag, as it is just that small.

And our replies were focused on the generator as that is initially your biggest concern. One of your top priorities in the sound department is dealing with and getting rid of (or at least reducing) any competing noise sources.


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Tom Galli
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 15, 2020 at 2:09:05 am

I acknowledge that reducing sound is part of the job.

Hopefully, you will acknowledge that removing all extraneous sound is impossible.

Whatever ambient sound remains, there are times I question if I'm hearing it because it's in the mix, or because it's penetrating the isolation value of my headphones and reaching my ears directly. This is what noise-cancelling headphones are specifically designed to combat. So, if I may ask again, why do you consider the use of such a "horrible" idea?

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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Ty Ford
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 15, 2020 at 2:12:30 am

Tom,

That has been asked and answered. Please move on.

Thanks,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Tom Galli
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 17, 2020 at 11:41:18 pm

Thanks for the tip on the headphones! Mine arrived today. They definitely provide more isolation than anything else in my current inventory. They're certainly comfy enough to wear for 15 minutes; I look forward to trying them on a shoot.

Still, even with 45 dB of isolation, I can hear the clickety-click of my keyboard as I type this, and the laughter of students in the classroom down the hall. Are my ears just more sensitive than average? I find that hard to believe; my youthful love of rock and roll has translated into middle-aged repercussions. My hearing is about average for my age, but I do have tinnitus. Even with hearing loss and tinnitus, these new muffs mark an improvement, not a solution, to the issue of "is it in the mix, or just in my ears?"

I'll keep looking, but thanks again for the link!

Tom G

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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Richard Crowley
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 27, 2020 at 6:19:42 pm

[Tom Galli] ""is it in the mix, or just in my ears?""

THAT is the reason to NOT use "noise-cancelling" or any other consumer-scheme technology when doing serious professional work.

Noise-cancelling headphones WILL reduce/remove ambient repetitive noise from what you hear in the headphones. Unfortunately, that INCLUDES reducing/removing the ambient noise that you are RECORDING. So you don't know (until it is WAY too late and too expensive) that the generator (or the airport or the interstate highway, etc) was a problem that you didn't hear on location.

That reduces your professional talent to that of a rank amateur who doesn't even think about ambient noise because they have no experience understanding how microphones work (vs your ear/brain system) when it comes to rejecting ambient noise. If you have tricked yourself into not hearing potential problems, then you can't deal with them properly. And presumably getting good, clean dialog recording on location is why they are paying you.

As you have surmised, the generator is another self-imposed problem (like using noise-cancelling headphones) which is easy (but not necessarily fast or cheap) to mitigate.

If you have not already encountered it, highly recommend this document which you should read and share with your producer/director/AD, etc.

http://filmsound.org/production-sound/openletter.htm

---------------------------------------------------------------------------------
Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder.


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Ty Ford
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 27, 2020 at 6:28:04 pm

Dear Tom,

You have been told how and why your thoughts will get you in trouble.

I'm not sure we can be of further assistance.

Your tag line, "The difference between theory and reality is that, in theory, there is no difference between theory and reality." presents an interesting conundrum.

Even in theory, your idea will not work. Please test it before the reality of it bites you it the butt and tarnishes your reputation.

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Tom Galli
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 27, 2020 at 7:57:17 pm

[Ty Ford] "You have been told how and why your thoughts will get you in trouble."

You know, I really don't understand the hostility here. Your response consisted of "Don't do it." David's was "It's a horrible idea." Where is the how or the why in either of those?


[Ty Ford] "Even in theory, your idea will not work. "

See, again, you throw out a statement with no support. That's not discussion, it's browbeating. Why is the idea so offensive to you? The concept is to reduce ambient sound and allow for critical listening; how is this different from having sound isolation headphones, or working in a quiet environment?



[Ty Ford] "Please test it before the reality of it bites you it the butt and tarnishes your reputation."

Yes, absolutely! I rely on tried-and-true methodologies. You'll notice that I ran out and bought the amazing cans David mentioned.

I suspect that sound cancelling technology is immature, but it sure looks promising. If you were to have suggested, 20 years ago, that taking an in-line noise filter to a shoot was a good idea, you'd have been roundly scoffed. Now, it was your go-to response, and one supported by others. Why is it crazy to think that, 20 years from now, sound cancelling monitoring won't be the norm?


[Ty Ford] "I'm not sure we can be of further assistance."

I'm interested in discussion. Informed feedback. Maybe even someone who is experimenting with the concept. If all you're interested in is telling me "no," mission accomplished. Feel free to ignore my continued curiosity.

[Ty Ford] "That has been asked and answered. Please move on."

Does it really hurt you so much to allow exploration of a valid question?

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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Ty Ford
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 27, 2020 at 9:46:54 pm

[Ty Ford] "You have been told how and why your thoughts will get you in trouble."

You know, I really don't understand the hostility here. Your response consisted of "Don't do it." David's was "It's a horrible idea." Where is the how or the why in either of those?

Dear Tom, There is no hostility on this end.


[Ty Ford] "Even in theory, your idea will not work. "

See, again, you throw out a statement with no support. That's not discussion, it's browbeating. Why is the idea so offensive to you? The concept is to reduce ambient sound and allow for critical listening; how is this different from having sound isolation headphones, or working in a quiet environment?

No, Tom, these are facts. Rail against science if you want, but please keep me out of it.



[Ty Ford] "Please test it before the reality of it bites you it the butt and tarnishes your reputation."

Yes, absolutely! I rely on tried-and-true methodologies. You'll notice that I ran out and bought the amazing cans David mentioned.

I suspect that sound cancelling technology is immature, but it sure looks promising. If you were to have suggested, 20 years ago, that taking an in-line noise filter to a shoot was a good idea, you'd have been roundly scoffed. Now, it was your go-to response, and one supported by others. Why is it crazy to think that, 20 years from now, sound cancelling monitoring won't be the norm?

Dear Tom, I don't care. I'll very like be dead.


[Ty Ford] "I'm not sure we can be of further assistance."

I'm interested in discussion. Informed feedback. Maybe even someone who is experimenting with the concept. If all you're interested in is telling me "no," mission accomplished. Feel free to ignore my continued curiosity.

Dear Tom, if you peruse the posts, I don't think you'll find a lot of discussion. The main crew who hangs here, myself included, have day jobs and are not paid to hang out.

[Ty Ford] "That has been asked and answered. Please move on."

Does it really hurt you so much to allow exploration of a valid question?

Tell you what. Report your question and open it up for discussion.

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Tom Galli
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 27, 2020 at 7:40:13 pm

[Richard Crowley] "If you have tricked yourself into not hearing potential problems, then you can't deal with them properly"

Now, that's an interesting perspective. I'll have to chew on that.



[Richard Crowley] "Noise-cancelling headphones WILL reduce/remove ambient repetitive noise from what you hear in the headphones. Unfortunately, that INCLUDES reducing/removing the ambient noise that you are RECORDING."

See, I think a great many people misunderstand how noise cancelling headphones function. It is not like you seem to be describing. They're designed to eliminate ambient noise, not noise in the signal. For example, when I travel, I have noise cancelling headphones. They do a fantastic job damping the noise of the engines and such, but still play the movie's soundtrack perfectly. Even, and I need to be explicit here, even if that soundtrack has the noise of jet engines in it! The only noise being cancelled is what's being picked up by the microphone built into the headphones, which is fed out-of-phase to the driver; no filtration is applied to the incoming signal.

That being said, it seems to me a lot to ask of a single driver to be doing 2 tasks at once, and I suspect this is why people complain about noise cancelling headphones coloring sound, which they most certainly do.

[Richard Crowley] "If you have not already encountered it, highly recommend this document which you should read and share with your producer/director/AD, etc."

That's an old favorite! I do love to forward it to directors when I work with them for the first time.

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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Richard Crowley
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 30, 2020 at 4:52:10 am
Last Edited By Richard Crowley on Jan 30, 2020 at 4:55:00 am

[Tom Galli] "They're designed to eliminate ambient noise, not noise in the signal."
Yes, that is true. But remember that WHILE YOU ARE RECORDING:

THE NOISE "IN THE SIGNAL" IS THE SAME AS THE "AMBIENT NOISE".

That is because noise-cancelling headphones were designed for the purpose of PLAYBACK of PRE-RECORDED audio in the presence of LISTENING-ENVIRONMENT noise. When you use them to monitor WHILE RECORDING, they will LIE to you by removing the background noise so that you are not aware that you are recording it. THAT is the major reason why it is a bad idea.

---------------------------------------------------------------------------------
Recording audio without metering and monitoring is exactly like framing and focusing without looking at the viewfinder.


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Tom Galli
Re: Revisiting: sound cancelling headphones for monitoring recording
on Jan 30, 2020 at 6:11:11 pm

Hey, an actual reason!

You're right... I was fixated on where and how the cancellation is applied, but not on the content. That makes perfect sense! If the noise was a 440 Hz sine wave, and the cancellation was an out-of-phase 440 Hz sine wave, then any other 440 Hz sine wave entering the acoustic space inside the earcup would clearly be affected.

The signal shouldn't be affected as much, I wouldn't think:
--The increased latency of the path through the recorder, not to mention differing distances between your ears-to-noise and the mic-to-noise, would mean that the phases weren't 180 degrees off.
--And any coloring that the mic imparted to the noise.
--And one would expect the amplitude of the cancellation signal should be calibrated to just enough to equalize the ambient noise, lest it become a source of noise itself.

But, as much or not, clearly it would have an impact. Heck, if distance plus latency were juuuuust right, the phases could align, and the noise cancellation system could actually increase the perceived volume of the offending sound, making you think a problem existed where there actually was none!

Thanks for that thought! I was planning some tests to see how things performed; thinking along this track has given me some ideas about how better to do that.

The difference between theory and reality is that, in theory, there is no difference between theory and reality.


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