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Noise Cancellation
Episode 448th July 2022 • Tech Talk with Amit & Rinat • Amit Sarkar & Rinat Malik
00:00:00 00:52:26

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There is noise all around us. Yet we hardly notice it. In today's world the ambient noise we are exposed to is immense. This causes irritation, sleep problems, hearing loss, decreased productivity, lack of concentration, miscommunication, etc. But we don't worry about it till its too late. Noise cancellation is a technology that's actively trying to reduce our ambient noise so that we can reclaim silence.

In this week's talk, Amit and Rinat talk about Noise Cancellation, what is it, what are its different types, how it works and a lot more!

Transcripts

Rinat Malik:

Hi, everyone. Welcome to Tech Talk. A podcast where Amit and I we talk about various technology related topics every week. This week, we're going to talk about a topic called noise cancellation. Noise Cancellation off the bat. It might sound like a very generic topic, but it has a lot of technical aspects behind it. And I think one of the important part when talking about noise cancellation is to define noise as well. Because one of the first things that we do is whenever we talk about noise cancellation, we talk about white noise like you know when we're talking but even music can be noise for example, now that we're talking if there was Background music playing, that we would contest noise and noise, so a lot of it is context-dependent as well. And this and also the technology that goes behind it. We're going to talk about it all today in our episode thank you Amit for coming up with this topic. Very excited to talk about it and learn from you as well because I know I know less about it than yourself, I think so. Let's start. What's your take on noise cancellation Amit?

Amit Sarkar:

Well, Thanks so much again Rinat for that good introduction. I think it is important to first define noise. But the reason I wanted to talk about this topic now is there is a lot of noise around us. There is noise from vehicles. There is noise of constructions that are happening around us there is noise in the transportation systems. So in London we have the underground system there is lot of noise when you travel underground. Then there is noise from music as you said it disturbs there is noise in the house from washing machines to say vacuum cleaners running there is the constant noise from different types of machines etc. And these are the different types of noises that we want to cancel. So we can have a very good experience. Whenever we are doing trying to do something, be it working, be reading a book, be just travelling and having a relaxed time or even sometimes sleeping. So that's why I selected this topic of noise cancellation.

Rinat Malik:

Yeah, very much so I mean there are so many different aspects of noise cancellation. And the technology that goes behind it also very interesting. And I remember when I was doing my postgraduate diploma in control engineering, a big part of it was noise cancellation and there was high pass filters and low pass filters and how to use them to cancel different specific type of sound with specific frequency. And that's just scratching the surface of noise cancellation when there's so much more that goes on and current technology . Especially in videoconferencing. I mean I you know we're using zoom for to record this topic this episode, but I've also known about other products other products available for video conferencing and other communication tools which also actively always engaged his noise cancellation technologies to give us a better experience when we are communicating and audio is very powerful when it comes to communication. Even not just communication in terms of when we're talking but also when we're listening to a story, listen to a speech or a talk, or even music. So music can be noise when we're talking but then when we're listening to music, there could be other noises and cancelling all of these so we get a better experience overall experience is very important and noise cancellation plays a big part. So how did how did it all start? I'm sensing there is there must be a point in as we advanced in our technology and started using communication or consuming content. There was a point that Okay, so we need to do something about the noise to, you know, to for a better experience for consumers. So how did it all start? You know Amit?

Amit Sarkar:

So, one of the stories that I've been reading is that noise cancellation started with aircraft pilots. So the aircraft pilots, they have to listen to the communication with a air-traffic controller and they have to fly the plane and aircraft engines, they make a lot of noise. So if you have ever flown in a plane, then you would know that the aircraft engines make a huge amount of noise. And to communicate with that noise in the background. It's quite important that you cancel those signals or cancel that sound and be able to listen to what the traffic controller is telling you and then able to perform certain actions. So that's where it all started. And if you've seen racing cars, if you've seen Formula One, then in Formula One what happens is you have a lot of people the mechanics from the team, they are at the paddock and they are listening to the or in the pit as they say they are in the pit and the pit lane and in the pit lane. They are communicating with the drivers and the f1 cars they make a huge amount of noise and that noise has to be first cancelled so that they can talk to the drivers and communicate to them where they are in the whole race of what's their position. How much fuel do they have, how much are how are the how's the car functioning, and the drivers can talk back etc etc. So it's very important that insert in such high noise environments that you have a way to cancel the noise and then be able to communicate and there are two aspects of it. One is the noise cancellation and the mic. So I'm currently wearing a headphone it doesn't have noise cancellation, but it has some it's over the ear headphones. And so those of you who are watching the video, you can see that I'm wearing the over the ear headphones so it's covering my whole year. So that's sometimes called as passive noise cancellation. I have a some kind of form around my ear that's not letting all the ambient noise, ambient sound entering my ears, but the sound is still coming in. And then I'm talking through a microphone. So the microphone itself is speaking a lot of noise. So that's why a lot of times when you're on a zoom call or Google meet, it's important that you mute your mic. So in this case now, Rinat has mute his mic so that the noise from his side is not picked up from the microphone. Otherwise you will not have a very good experience listening to this podcast. So these are the two main types of noise cancellation, one is for your hearing, and one is for your speech. And it is very important that they are both cancelled now when we talk about noise, the human hearing, or hearing in general is measured in decibels. So up to 85 decibels is is good enough for human hearing anything higher than that it can cause your damage and sometimes permanent ear damage. And that would mean hearing loss. That could mean tinnitus. I have tinnitus. So I just wanted to share it with everyone. So it's a ringing sound in your ears. And that's constantly there. It's there. 24/7 365 days of the year, and I've had it for a couple of years now. And I had spoken to my doctor, and they said that it's because of some high frequency noise that I was that I was exposed to. It could be the noise from a fire cracker. It could be the underground, the tube that I take in London while commuting to work. It could be an aircraft engine while boarding the aircraft, etc, etc. So it could be any high frequency noise for a very short period of time. That caused permanent ear damage to my ears. And I sometimes wish what if I had noise cancellation is so the noise cancellation ear for that would have saved my ears. And that's why I wanted to talk about this subject because it's quite personal to me.

Rinat Malik:

Yes, absolutely. And this is very interesting how you sort of compared microphone and speakers with the human experience and the hardware we have to listen to sound and sound engineering is fascinating on itself. I mean there's so many aspects of it. And so many things they have to think about. And so many sort of technologies that goes behind it. It's amazing. And a big part of listening to sound is microphone and you know as human counterparts we use ears to listen and I remember this phenomenon. This happens when you are in a party or somewhere where there's a lot of ambient noise and then you were talking to someone and then suddenly you hear someone called calling out your name from around and your brain picks that up. So what is happening in in with our ears as humans, we are always open our ears are also always listening to all the sounds that are happening. And our brain is sort of doing the noise cancellation so we only listen to the parts that are important to us that are contextual to us, too. You know, if I'm talking in a party, then I'm talking you know, I'm listening more to the person I'm talking to. But then sometimes brain makes a mistake from the all the ambient noise if something sounded like that's important to us, we suddenly feel like Oh, someone called our name or something important. So the noise cancellation happens in humans in our brains. But our ears also listen to everything that that sort of comes through ambient noise and everything else. The same thing is happening in in hardware in computer technology as well. Microphone is listening to everything and that's probably in early days of recording sounds and everything. That's that was what's happening. And then the need for noise cancellation sort of came about because microphone, just like yours picks up everything. And then the noise cancellation technology sort of weaves out all the unwanted noise and only keeps the noise that are that are relevant. Now. One of the very basic technology in doing that was to just identify the frequencies which are off you know off noise. So, you know usually if I mean you are talking our voices have a particular frequency and if there is a you know, cars speak in the background or something else traffic noise or something they will those will have different frequencies. But then again, it's not always in like black and white separation. Sometimes there are overlaps. In early days there were noise cancellation where they would just try and identify the most of the frequencies of noise isn't then get rid of that. But then the what you're left with is also kind of becomes unnatural, because even though our voices have you know, mostly, you know, a range of frequency but we still go up and down as we speak. You know, especially when you're sounding particularly

Amit Sarkar:

angry, angry or like ecstatic, etc. Yeah,

Rinat Malik:

yeah. So as an F and these kinds of sounds have you know, a higher range of frequencies. So when you cut the higher part of the lower part of your voice also becomes a little bit unnatural, which is also not really what we want. We want our voice or whatever is the main subject of the sound, to be clear, and less echo and natural. So nowadays, we've kind of became more advanced in identifying exactly what it is that we want to get rid of. There are sound engineering or you know, sort of dealing with frequencies is actually quite beautiful. I mean, mathematically as well, because all of these things can all of the different sounds can be a wave function, and then you can do various mathematics and various control engineering, algorithms to implement those to modify that wave function so you get exactly what you want. So because there is one beautiful one like central thing that that can express everything in a sound that makes it really, really amazing in mathematics as well. So that Yeah,

Amit Sarkar:

Yeah, absolutely. And you said it. I mean right that whatever is music sometimes can be noise as well. And there is a difference between hearing and listening that people keep talking about. So in clubs in very have a very, I mean, very, you have a lot of people talking, where you have the music playing in the background. It's sometimes difficult to have conversations as well. But suddenly you hear your name and you are like, okay, yeah, my name has been called. So let me just go and see what's happening. So it's, it's incredible how our minds perceive. And you said, right, our ears are constantly hearing for noise. Even when we are sleeping. We're constantly absorbing the sounds. And sound is actually quite wonderful. So you have sound on planet Earth and you might have sound where there is even a slight bit of atmosphere but you can't hear anything in space. So you need air to listen and hear things. And that's why we are able to communicate with our mouth and with speech and it's incredible, like how our ears have evolved to capture that. So the sound is basically compression of air. And there are hair follicles inside our ear drops inside our ears and there is a eardrum, and that all vibrates when the compression reaches our eardrums. And based on that our brain gets the signal interprets it and then it tells us what we're listening. So even when I'm talking my brain is listening to what I'm talking so I can hear myself talking. I can hear you talking as well. So it's incredible how it works.

Rinat Malik:

Yeah, absolutely. And this is another important part that I would also encourage the audience to be aware of as well as you know, maybe take action based on the lifestyle that you currently have a lot of the ambient noise that we're exposed to some of them you were mentioning, like when boarding an aircraft or just you know travelling on the underground or just in a car. I mean, the decibel of noise that a car makes when you're driving you don't notice it but it's actually really high. If you are commuting in car every morning and evening to and from work or anywhere else, your ears are being exposed to these noise which are harmful to those the hair that that kind of listens to all the sound that happens around us. And these hairs. They're not like our identity

Amit Sarkar:

And even the eardrums the hairs at the ear-drums

Rinat Malik:

the these are not like these are not like the regular hairs we have you in our head, etcetera. So these ones the damaged ones, that's it they don't they don't regrow or they don't. There are there are 1000s and millions of it. But once they're damaged, they don't regrow or they don't get sort of they don't heal itself. So once you lose some of that you've completely lost it. And then based on that and few other things that happens with age, you can hear less and less frequency and there are various tests available online as well that will generate frequencies of different Hertz. And then you'll see at which point you start listening to that to the sound and you can tell that at which stage you are with your ear health. Yes. So

Amit Sarkar:

that's actually the test I had to undergo to identify what kind of frequencies so I basically high frequency hearing loss. So if that if there is ambient noise and if I have to have a conversation, say in a club, it will be difficult for me to hear what you're saying. Because there's a lot of ambient noise. So basically that that's the and you're exactly right. They make you wear headphones, and they ask you to click a button. Whenever you hear something. They don't tell you what you're hearing, but they ask you to click something when we add something and I started looking at they plot a graph and then they could see which part of the hearing or the which part of the frequencies. I click the button in which parts I didn’t and based on that they can tell which are the frequencies I can't hear. And as you are rightly, you rightly said that hearing loss is actually irreversible. So you cannot recover your hearing with age you of course here so you must have sometimes seen old people asking can you please repeat that or can you can you be a little more louder, etc. Or sometimes people say can you please be soft? Don't shout too much because they get like they get perturbed. Like why is someone shouting at me even though you think you're not shouting but someone else thinks you're shouting. So it's very subjective. But it happens to all of us and it's incredible.

Rinat Malik:

Yeah, absolutely. And yeah, that's why I want I want the audience to know that because it's irreversible and a lot of the times we are not notice how much ambient noise is around us. So to just be more mindful of this mode not to expose yourself as much or whenever possible. I mean, I've spoken to a sound engineer every time he used to drive to and from work he used to have like a long commute one and a half hour drive is to put earplugs in his in his ears when he was driving because he more than anyone else knew the you know the damage it causes and how irreversible it is. So, yeah, I mean, no matter how lame you might think that is, but that is that is definitely a good practice whenever you're exposed to a

Amit Sarkar:

But Rinat, I just want to correct you. Uh, you should be able to hear people honking you should be able to hear vehicles coming behind. So please make sure that you are when you're driving. You are alert. It's good to cancel the noise, but you should be able to hear oncoming vehicles. We are not recommending you to wear noise cancelling headphones. When you're driving. You're just that be mindful of it because it could be a traffic violation because you're not able to hear vehicles behind you. You're not able to hear ambulances. You're not able to hear police vehicles. And there could be a car accident. That could be some emergencies and you might be a hindrance rather than moving on. So

Rinat Malik:

Absolutely, that you clarify that. Yes. So obviously, car is not the only case where you're subject to ambient noise. So absolutely. And then there are many, many other times when you are also exposed to noise, which is part of having fun, like if you're in a party. You also don't want to be don't want to isolate yourself with noise cancellation but you want to engage and sometimes you can't avoid for example in a movie theatre, etc. But you know, whenever possible and whenever it's safe to do so etc. Then do be mindful of it and when you can you know, make yourself not exposed to it. Do your best to sort of save your hearing. But then, you know so far, we talked about the hearing of humans but then there are now you know, let's move on to the technology behind it. And how we you know what we do to sort of cancel the noises in for example, in this this video conference call.

Amit Sarkar:

So yeah, let's start with I mean, let's start with what we hear. Okay. And we have we, we hear normally through our ears, and normally now we have headphones, and those can be wired or they could be wireless. And then there are earbuds that go inside your ears. And they create this kind of a seal and those could be wired or it could be wireless. Now in order for the headphones to cancel the noise, they need to listen to the sound. So there are two sounds that are there when you are listening through and headphone. One is the sound that is coming out of the headphone. The it could be music, it could be a movie that you're watching, it could be in a conference call. It could be people talking so that's the noise that's coming out of the headphones or earphones and then there is ambient noise. So we don't want to cancel the noise that's coming out of your headphones or earphones we want to just cancel the ambient noise. So there are two ways you can cancel the ambient noise and that is by placing the mic outside the headphone or the earphone

Amit Sarkar:

So it's constantly listening. And then it cancels that noise and then it sends it to the headphone speakers and then the headphones speakers just sent you what it's supposed to say music speech, etc, and the external ambient noise is cancelled. Now how it is cancelled. So as Rinat said that there is a frequency and the frequency has a curve. It goes up and down. You must have seen a sine curve if not, please google it. It's a very beautiful curve. It's very simple curve. It goes up and down along an x-axis and along the y-axis. And when that curve goes up and down and how fast it goes within one second that's defined as the frequency. So if we see that curve, when an ambient noise is coming, we analyse that using a microprocessor or a chip inside the headphones. And that chip then translates it and then inverts the signal inversion means it so if the frequency is high, makes it low. And if the frequency I mean sorry, if the amplitude is high, it makes it reverse. So it's like saying if there is plus one, you add minus one to it, so it cancels and becomes zero. We'll share some links to show it picto graphically like how it looks. But if you can understand what an inversion means, it's simply a basically negating what you're hearing. So the opposite of a frequency is what the noise cancellation chip does. And then using the speakers of the microphone oh sorry, the headphone or the earphone, it sends you the signal. So that's feed forward. So it means it is listening from outside the headphone. Now, there could be also what you are listening. So that's feed back. So the mic is actually inside your headphone. So in this case, what happens is that the mic is trying to listen what you are going to hear. And if you're hearing noise through if you're hearing noise inside your headphone or inside the earphone, then it will try to cancel that so that's feedback. So one is feed-forward. The other is feedback. And then there is a Hybrid. Hybrid is basically having a mic outside as well as inside and then combining that and trying to cancel both of it. Of course there are pros and cons of both. Both sides. Noise Cancellation works very well. When there is a constant frequency. Say you go into a Air-craft or say you're travelling the tube, the sound of the tube is always constant. It never goes up and down too much. Maybe at a turn. Maybe when it's breaking. It goes up and down. But normally more or less. It's the same frequency. So it's easy to cancel. But if there is a sudden change in sound, say someone suddenly shouts or say there is suddenly there is a high pitch print because a car crosses then it's sometimes difficult to cancel that. So normally noise cancellation works when there is a constant sound so it's very good. For ambient noise or a same frequency noises. But if the frequencies keep fluctuating, then it's not that good. So that's a hybrid one. And then we keep hearing about the different types of headphones like Active Noise Cancellation just noise cancellation, Adaptive Noise cancellation, adjustable noise cancellation, and many other modes. And these are the kinds of technologies that the headphone companies want you to understand. Of course they say that okay, ours is the best but what does it actually mean? Noise cancellation is inversion. Active Noise Cancellation is dynamic.

Amit Sarkar:

So noise cancellation when I say inversion is it knows a specific frequencies and it cancels those frequencies only. Active noise cancellation is that it hears in real time and then cancels it. Adaptive is when it's when you're when you're hearing something based on your surrounding and based on what you're listening, it will adapt and then it will cancel. So it will not cancel just standard way. It will cancel based on what your surrounding is. So adaptive, sorry, noise cancellation and active noise cancellation is same. Adaptive is different, it adapts to the environment. And then you have adjustable noise cancellation as well, where you can adjust how much noise cancellation you want. Because sometimes you're in the airport you want to hear the boarding announcement. So you want to not cancel everything. So you want to keep hearing the ambient noise as well. So that's again important and then you have something called transparency mode. So without taking off your headphones if you want to hear the ambient noise, so either you cancel the noise or there is a mode called the transparency mode, where you can hear the ambient noise without actually taking off your headphone or earphones, and that's transparency mode. And of course you have adjustable modes, adjustable transferring transparency mode and so on. So these are the different types of noise cancellations, and the type of technology in which the companies are trying to sell their products. So you need to understand what kind of headphones you're buying. Because based on what noise bothers you, you need to decide whether you want to feed-forward or feedback and with active or Adaptive Noise Cancellation because that's very important. Based on your daily habits. And based on how your day looks like you travel a lot. You read a lot. How's your sleep? Are your neighbours making a lot of noise? Do you normally commute a lot? Do you normally fly a lot, etc, etc. So those are the various factors that would go in deciding what kind of hearing product you want to buy, which is deciding what kind of noise cancellation you want to have.

Rinat Malik:

Yeah, absolutely. You know, it's amazing how in recent days, there are so many newer technologies which is built upon you know, identifying the frequencies which are of noise and which are which are not of noise and then isolating them and removing them etcetera. But at the core of this technology, high pass, high pass filter filtering remains.

Amit Sarkar:

Absolutely, yeah. So you want to hear something and then you want to filter it out, and that the way you do it is by cancelling it by version of the frequency. So yeah,

Rinat Malik:

Yeah, I've mentioned high pass filter and low pass filter earlier a little bit, just touch upon it, but just to give you a bit more of detail. So we have frequencies you know, we have like sound frequencies, some of them are say for example us talking and some of them are ambient noise and our talking frequencies are usually hopefully different than then then the noise if they were exactly the same or very similar, then it would be more difficult to identify and then isolate. But one of the one of the benefits is usually the noise is either higher frequency or lower frequency the high pass filter. It's the name of the filter that lets the higher frequencies pass through and low pass filter less the lower frequencies pass through and if you implement both, then it cuts off the top and the bottom of the of the spectrum and lets the middle part pass through. And usually that's our conversational voice anyway. And obviously, you know to know whether how high or how low do you need to pass through and what you need to isolate is, you know when you adapt based on what you're hearing, that's the Adaptive Noise Cancellation I mentioned. So yeah, I mean, and nowadays I hear AI is also being implemented to identify which one is the context based sound, for example, and it could be very different because when you're listening to music, that's the context based on that's what you want to listen to and that would have a much higher range of movements. And when we are Talking that’s only a different thing and then imagine in a content or in a video you're watching which has both music and a conversation where they has an intro with a bit of music and then you know some of talks some time and then goes back. Like another way Video part which has music or sound or car accident video, which and then you have to adapt these things and understand which one is context based sound and AI hopefully. Which AI will add currently also is turning out to be much better and identifying these context-based noises and giving us you know, better experience. For example in zoom right now we're talking. I think if we both stayed quiet for three or four seconds, it would be as if everything's muted. None of the noises will be transferred. Like even though there are some traffic happening around me right now. I don't think you can hear it Amit. Because it is actively being cancelled.

Amit Sarkar:

It is yeah. So that's the microphone part which we will talk later. Yeah.

Rinat Malik:

Yeah, yeah. So, I mean, I usually when we're talking when you're talking, I mute myself, but even if I didn't, I think there are technology right now at the moment being active that would kind of make my site completely quiet. And then you know, when we edit our videos, we also do a bit of noise cancellation, as when necessary, as well. So yeah, it's ingrained in everything that we do. Digitally especially. It's kind of a default setting. Nowadays to have noise cancellation, any sound content,

Amit Sarkar:

yes, Zoom, Google-meet. They all have this setting where you can cancel the noise when you're actually speaking so that if there is a vacuum cleaner running, if a baby's crying, if there is a washing machine running in your house, then they don't send those noises back to the other side. So the listener, they don't hear those noise, they will hear the speech. So that's the noise cancellation on the microphone. But I think when we talk about the headphones because I just want to cover other topics as well. That noise cancellation could need not be that when you're hearing something, it could be that you just want to cancel noise. You don't want to hear anything. You're not hearing but you just put on the headphones and you just turn on the noise cancellation. And that's it. And you just go through the airport you just go through the commute, without listening to anything and then you're enjoying the silence. And I think that's also important to understand that yes, some people need that as well. They don't want to hear music. They don't want to do anything. They just want to protect their ears and it's good to have such kind of headphones so that you can enjoy the silence when you're commuting, travelling or even sleeping. So, so those are the different modes. And I mean, noise cancellation is so when we talk about noise cancellation, it could be also when we are trying to use drilling machines. So it's very important to have ear mufflers when you are doing some DIY work in your house. I do a lot of DIY work in the house. I have a drill machine. I have a lot more and they make a lot of noise. I have a Dyson vacuum cleaner. It makes a lot of noise, and I get irritated by the sound. So now I've started wearing ear mufflers, so it helps protect my ears from the high frequency. It's not headphones but that's what you call as passive noise cancellation. It's blocking the noise by not listening to it. It's just blocking using the mufflers just having some foam on yours to block the noise and it's it actually works. Of course it doesn't block all the sound so that I can hear some people coming in, etc. But I think it's very important. So those are the things that are related to your headphones. And know why this is important because people get irritated people get angry. People lose their sleep people. People have different kinds of issues, etc. So it's very important that you protect your hearing and hearing is one of the things that is getting abused on a constant basis. Because we are now have so many devices in our house that are constantly producing sound that we don't know what actual silence means because we are not used to silence anymore. We are just used to some kind of noise. Or you as Rinat mentioned white noise

Rinat Malik:

Yeah, absolutely. I mean as you mentioned, you know, using headphones just for silence nowadays. I think I've heard of these kind of some kind of smart headphones, which has a microphone built in. And you know, you're not playing anything you're not listening. You're just putting them on and then actually listens to the ambient sound that's happening outside and tries to identify the sound that you want to listen to like for example someone calling your name or a conversation etc. And that that microphone noise the microphone picks it up, and then it lets you it plays those songs in your headphones. So that's that I thought that was very cool.

Amit Sarkar:

That is very cool. Yeah, because

Rinat Malik:

I couldn't really find it. I'm sorry, audience I know. The technology exists, but a little bit to get it myself. But yeah, I mean, say for example, you're doing vacuum cleaning, wearing headphones. Sorry headsets for noise cancellation. And you know, say for example your partner is calling you you do want to hear that, right?

Amit Sarkar:

Oh, Yes, I think Sony has their headphones, but I don't know if it works like that. So what happens is, if you take the headphone off, it stops the music, and if you tap the headphone, it can it automatically starts listening to something like that,

Rinat Malik:

like with tapping sort of buttons now is quite complex, but no, I'm talking about the microphone, integrated microphone always listening and understanding which sound you might actually you want to listen to and then playing that in your in your ears. I've heard I've heard about it. I couldn't find that product. But yeah, I mean, either it exists or someone was probably talking to me about an idea and hopefully, if the audience can't find it, maybe they want to patent it or make this as a product. The tech savvy audience base that we have. But yeah, going back to the human experience of sound I mean, sometimes we don't we don't realise how important and how powerful our ears are in terms of listening to sound. And we could identify very slight change in the sound we're hearing. A lot of even in different cultures like the tone of someone's spoken words. We identify like whether someone is angry or frustrated or different emotions, not just probably the negative, happy or angry, happy or sad, but kind of tell whether they're frustrated, they're angry, they're sad, they're feeling hopeless, or happy, joyful, I mean all different things you could identify with, with sudden very subtle changes in in their voice and that's just one aspect of changing the frequency but then you could also identify exactly the direction of the noise comings. Where it's coming from and there was a test like where, you know, three hundred and sixty degrees around you on a on a horizontal plane. You know, if you divide it by a degree in a in a large rooms, you know, creative like a makeshift room which is circular and you create like a three sided three each degrees you divided, you know, you mark it, and then if you put a speaker in any of those degrees, any of these locations and play a sound, and you're blindfolded you don't know where the speaker is where the sound is coming from, and the and the sound is played in the sneaker behind you or wherever that 360 degrees around you. You would be able to tell with one degree of accuracy, where exactly that speaker is. And that's an evolutionary view. This is built up because you know, you know we need to know where you know when we're before civilization in case man we needed to know where

Amit Sarkar:

Danger is coming from.

Rinat Malik:

Danger it is and you know, where the sound is exactly what which direction So, this is built within us and it's really powerful. And we might not notice it, but we use that all the time. And you know, even when producing music or movies in a digital world we use that you know, as a stereo sound. And when you go towards 3d movies, if there is a lot of things happen even the sound world as well that's why they are not just bring you the visual experience but they're also changing the stereo of sounds in such a way that you experience the sound is coming from not just right or left which side right or left nowadays, the technologies that sort of sophisticated so yeah, it's amazing how powerful it is and how little we notice of that. If the technology is less noticeable. A lot of people say that that's a that's a sign of how good the technology has, yes. Not supposed to be, you know, hindering your life or you shouldn't be noticing if you're living your life smoothly, then you shouldn't even be noticing the technology and that's what's happening in sound world about for a long time actually. So yeah, it's really fascinating to learn about sound in in general as well as how the noise cancellation technology is making your lives better every day without notice.

Amit Sarkar:

Absolutely, absolutely. And I mean, of course a lot of people might think that, do these noise cancellation headphones, cause ear damage or anything and are they harmful? Or the radiations? Well, it's nothing like that. It's just frequencies and it's inversion of the frequencies. So there is no actual harm. In wearing headphones, there is no radiation coming out of it, and it's perfectly safe. The some of the side effects are people who are very sensitive to certain kinds of frequencies. They might feel a bit dizzy, etc. But it's in very rare cases. And it's to do with the because what happens is when the sound is inverted, it still some kind of, I mean, it tries to cancel it, but sometimes it can't cancel everything. And there's still some frequencies that are coming in and those frequencies might be low, and they might be causing you trouble. Because the brain thinks that you are in motion, but you're actually not so it causes some dizziness. And that's a side effect, which only very few people go through. But this is something to be mindful of that sometimes noise cancellation can cause this dizziness, but in general, it's very safe to wear. I've tried those headphones myself at a lot of airports and I really enjoyed and I think if you want to protect your ears, I think that's the way to go forward. You can get an over the ear headphones or you can get those earbuds from Apple, Google, Samsung, etc. And they are really good. Now let's come to Mic. So the microphone so I'm currently talking through a microphone. Renato is talking through a microphone. His mic is on his table. My mic is close to my mouth on the headset that I'm wearing and they are both picking noise or sound and they are picking the ambient noise so there is ambient noise coming from my laptop fan. So I'm currently recording this video from the laptop and there is ambient noise from the fan that's coming I don't know Rinat that can hear that noise. Say yes or no

Rinat Malik:

no, I actually I'm not hearing anything else.

Amit Sarkar:

Yes, so the basically the microphone has a soft like a cushion or foam around it. So I think that's trying to do passive noise cancellation from the microphone side. And now there is technology that does active noise cancellation. And that means that whatever speech that is going through the microphone and the ambient noise, the software then sends only the speech and not the noise. And that's what is done by the software. So Google-Meet, Zoom and the Microsoft Teams. They are actively cancelling the noise that's coming from your microphone, identify what frequencies are the speech as Rinat mentioned, it's frequencies or within a range. And anything above and below is not. I mean it's noise and then let it pass through. So that's again active noise cancellation but that's through software and sometimes you're going

Rinat Malik:

Lets sort of put out this example that I just thought of that one once I was talking to my partner in WhatsApp and I wanted to show her music that I liked, and I was playing that music on my computer while on my phone and I was when she wasn't able to hear the music at all. And that was because WhatsApp was completely you know, like completely cancelling that's in the music that's playing loud around me but she was hearing me quite well. So that's how well the noise cancellation has gotten this to me that there is you know loud noise. Well in this case, I was actually wanting my partner to listen to that music but she wasn't able to at all and I was quite impressed. But also annoy at the same time because, you know, I didn't get what I wanted to do. But I was impressed with the level of noise cancellation and how good it has become. So yeah, I mean that's these are I mean, but you were I mean it's an important distinction. I think, you know, as we mentioned zoom and video conferencing there are other ones like Cisco and Lutyens etc. But they are doing a digitally but we also have a various mechanical or physical ways of noise cancellation in one in musical while there is something called Pop shield which is placed right in between the mouth and the microphone, which kind of filters out the various popping noise that happens when we are talking like the s and t etc. So there are all of these mechanical, you know before around your microphone. All these things are mechanical devices that are kind of doing noise cancellation, but then there are digital ones that are also just mentioned Yeah. So yeah, continue.

Amit Sarkar:

So yeah, absolutely. I think I was about to get to it, but you mentioned it, which is very good because you might I mean there are a lot of people who watch or listen to podcasts at the here crystal clear sound and how do they achieve those crystal clear sound? If they have so much ambient noise around them. Sometimes they are in a very soundproof room, but there is actually no noise they make sure that any noise coming from their machines are actually cancelled. And they use noise cancelling headsets and they use noise cancelling microphones or other ways is having a plate in front of the mic. So you must have seen a lot of podcasters it happens when you listen to singers recording in a soundproof room, so they try to have a plate in between them and the mic so that no hissing sound or all those sounds are filtered. Because or take just taking a breath. So I'm talking and then I take a breath and then I continue to talk. So that sound itself is kind of noise and you don't want to hear that when you're singing. So they actually cancel those noises through this through this plate and then of course on the microphone itself. So a lot of podcasters and a lot of people now on who are working from home they have professional microphones. So there is microphone from Blue Yeti which is I think the most common one. I think Rinat you mentioned you have a Blue Yeti microphone. Do you have a Blue Yeti?

Rinat malik:

No no. The one I have is Rode.

Amit Sarkar:

Rode yes Rode. Rode is another good company? Yes. Yeah,

Rinat Malik:

I'm not using that right now. So just FYI audience this is not an sound sample of Rode microphone. But yeah, that's the one I use a lot of the times.

Amit Sarkar:

So yes, so that's a Rode. There is Rode, there is Blue Yeti and there are many other companies and they on their hardware. So when they pick up the sound on their microphone, they also pick up the ambient noise, they cancel the ambient noise and then they transmit that sound through the cable or wirelessly and then they record that sound on your computer. And that's how it works. And it's incredible how and it's the same principle. So you have a microphone it picks up the sound you have a chip that inverts noise It keeps the speech part and it cancels everything else and then it gets recorded. So or at the listener on the other side. hears only what's needed and everything else is cancelled. So it's a very simple thing, but it is very powerful. And these days it's now getting in more and more headphones and microphones is because of the technology the chips have become very powerful. They've also become very small. So you can put a very small chip inside a headphone and still get active noise cancellation because these chips have to do a lot of calculation there to listen to a lot of frequencies they have to differentiate between human voice and many other ambient noise they have to analyse that they have to invert it, they have to send it back. They have to listen. So they have to do a lot of these things. And these chips have to be again very small so that they can fit in a very combat space. The headphones itself have to have microphones, if you're wearing a noise, if you're wearing a wireless headset, they need to have battery, the battery. If you're using noise cancellation, the chip is consuming power. So there is a lot of the battery consumption increases. So a lot of times when headphones are being sold, they advertise that with active noise cancellation. It's this much battery life without it it's this much battery life and etc. And with microphones normally what happens is you're plugged in so you don't have to worry about batteries. If you if you have a Blue Yeti or anything, it's USB or you can plug it externally, but with microphones normally you don't have a problem of the wireless part. It's only with the headphones. So the technology has improved a lot it is now making sure that these podcasts can be done by even people like us but very professionally with very low budget equipment. I don't have a very fancy headset it's just from Microsoft. It costs about 30 quid/30 pounds. It's not very expensive, but it does a decent job. And it just shows that you don't need very expensive gear. To start something you just need the will to start. So yeah

Rinat Malik:

Absolutely. So yeah, this this has been like a great talk. To be honest. I've learned a lot from through this talk as well. Hopefully our audience did the same. And yeah, I also enjoyed sharing some of some of my stories from the past and it was all of these things sort of came about as we started talking about noise cancellation, which I thought about for some time. But yeah, it's fascinating, to say the least in all of the technologies that are currently there and it's actually quite, it's not like a very recent outburst of technologies with improvement. Always had. You know, as long as soon as there have been sounds there was need to cancel the songs that we don't want to hear as opposed to the ones that we do want to hear. So yeah, it's been it's been really nice talking about it with you Amit. And hopefully the audience enjoyed it fairly and if there are any, any aspects that you didn't like or liked, do let us know. Our contact details are available in whichever outlet you're listening through. We do who will take the on board and any future topics that you guys would like us to talk about do let us know as well. Yeah, thanks. Thank you again audience for you know constantly letting us know the ones that you did. And we look forward to coming back to you guys every week with more and more episodes on different topics.

Amit Sarkar:

Thank you. Thank you so much again Rinat. It was really great talking. I really liked some of the examples because I think it's very important to people, for people to hear real life stories, because that's how they will relate to it. Technology is there to help us to augment our, our senses. And noise cancellation is one of the technologies that's helping us helping a lot of people who have hearing problems and also in protecting their hearing. So that's why I think it is great talking to you. And yeah, listeners and viewers. Please do let us know how you feel about our podcast and do give us any feedback that you want and do recommend us topics. And as we promised we will be with guests soon, so please keep listening and tuning in and hope to see you next time. Thank you

Rinat Malik:

Thank you everyone.