Acoustics of Restaurants

Actually, there’s no single view to take on this topic. Restaurants are theme-based, these days, and ambiance of older restaurants become their “theme” after a period of time.  Let’s talk about a few ‘themes’, and then we’ll look at some common  acoustical issues at such places.

Eerie Places

I once  went into a restaurant called Gufha. The word means “cave”. True to its name, I walk into seemingly absolute darkness, one bright sunny afternoon. After my eyes got used to the darkness, as the door closed behind me to shut out outside light completely, I realized the whole place has undulated, brown-coloured plaster work all over the walls – made to look like a huge cave we’re entering. The waiters were all dressed like Shikari Shambu.

The undulations on the wall provide for ample diffusion of sound and there are no sharp echoes, no sound of clutter – which is so unlike most restaurants  where “sleek” is the theme. The only downside was that the place had piped music being played – not sweet-sounding chirps, babbling brooks, gushing water etc,  but eerie night-time noises from the jungle. Crickets, the occasional distant roar – what have you. The place provides good quality acoustics, and good quality food, I must add. But you don’t exactly feel appetized listening to sounds of creepy crawlers. The acoustic ambiance is not just about reducing echo and reverberation, and preventing noise going out/coming in. The choice of music goes a long way in attracting certain types of clientele.

The other example I can think of is Cafe Coffee Day at Jayanagar 4th Block. It played such loud music, on such crappy speakers – high on treble, low on bass, and in a room where NO thought had been spent on acoustics, I had to take a disprin at the end of an hour. This was years before I studied acoustics at UK, and so I didn’t imagine bad music could do so much damage. I have sworn not to go into a CCD since.

Noisy Places

Restaurants can be deafeningly noisy – Koshy’s for instance. This one also comes under the category of “Quaint old places, best left untouched”. There are railway canteens that sound quieter than this one! But that’s the ‘theme’ at Koshy’s – old world charm, nostalgia, noise of people, noise of cutlery, noise of the kitchen, bright chequered tablecloth, old fashioned cutlery, etc. There are old, analogue loudspeakers mounted on the corners on top, with cobwebs on them. No point in playing them anyway. 😉 This one should stay as is. 🙂

However, newer places that are deafeningly noisy don’t get the discount of old world charm. Toit micro brewery in Indiranagar is a good example. The weekend I went there, we couldn’t hear ourselves shout. It was so noisy. Of course, noisy restaurants are a sign of good times for the restaurant owners, but I’m not so tempted to go there again if I have to spend a couple of hours shouting myself hoarse over the din for having gone there.

Quiet Places

On a regular basis, we expect “quiet” to be a standard part of a fine dining experience. To provide this feature, the restaurant owners have to make sure the kitchen door isn’t leaking noise, and if the kitchen wall is a lightweight gypsum construction, it shouldn’t leak out noise into the dining area either. Also, the place is to be carpeted for sure – footfalls are irritating when you’re looking for quiet. The other issue we see is a high roof, usually made of gyp, with various designs for diffused lighting. Designs are good – we acoustical engineers are not very fond of flat, parallel surfaces, but high roofs can lead to cutlery noise being amplified. Fine dining places must have heavy upholstery on the furniture, and plenty of carpeting in the open corridor spaces – sleek chairs, smooth floors, high roofs are a bad idea.

Places with Live Music

This one clearly needs specialized acoustical treatment. Thumb rules like the ones mentioned above can backfire rather badly. We’re always talking about money wasted, when we design in hindsight. Such spaces have to be optimized for clear speech, as well as live-sounding music. Too much carpeting will help speech, but kill the high notes, and too little of it will make conversational noise and music mingle with each other unintelligibly. Treatment is not always essential. Hard Rock Cafe in Bangalore is a lovely example. The place is located in an ancient stone building that once housed the Bible Society of India. As was prevalent during that time, the stones of the building  have a natural irregular finish, and so there’s ample scattering of sound at least in the HF range. The various artifacts displayed also help in scattering some mids. It works for speech as well as music.

Common Acoustical Issues

So, it’s not really possible to have a standard view here about acoustical issues, but let’s make an attempt to generalize. For a quick peek into the possible acoustical problems in restaurant spaces, here’s a good read:

HVAC: In general, the HVAC duct acoustics must be carefully calculated – certain critical distances can cause them to turn into roaring resonators. That’s not good for any kind of place – noisy, or quiet.

Kitchen Noise: These areas must be strictly isolated, with double doors spaced a few feet apart at the minimum. That way, when one door is open, the other will be shut. The doors must be acoustical doors – 6mm glass will not do much.

Foot falls: Contrary to what you may think, this doesn’t just imply treatment on the floor. It also implies isolating the ceiling from the noise on top, depending on the kind of space above. If the floor above contains a gym, or another restaurant, or an office space, care needs to be taken to isolate that sound.

DG set noise: Seems unrelated? Nearly every restaurant has one, usually right outside the main door. Nobody provisioned space for these things even 5 years back. Now it’s the norm to have one outside. The good news is, road noise will sometimes help to mask it.

Road Noise: At other times, road noise is the problem itself. Glass doors that are not framed, glazing that isn’t thick enough, will cause some noise to filter in. We’re not looking for studio-like quietness, so it’s okay to hear some, but occasionally, it’s bad enough to drown out conversation, especially on rooftop restaurants that aren’t really very high up. The Coffee Day at Jayanagar 5th block is located on the first floor, at the corner of one of the worst traffic signals in that part of town, and they’ve placed tables and chairs outside the room, in the balcony overlooking the signal.  I haven’t bothered to go in, but I can’t imagine myself sipping coffee, inhaling vehicular smoke, and shouting over traffic.

To summarise, for places that solely rely on good user experience for clientele, acoustics can be a big factor to determine how much time people spend at such spaces. Plenty of easy solutions are usually possible, and they don’t have to interfere with the theme that an architect or an interior designer has in mind. And if you thought architects and interior designers were the more creative of the species, I happen to know a couple of really creative acoustical engineers, who’ve worked with the interior designers to come up with spectacular looking furniture, with lighting inside them, which also work as tuned LF resonators to trap bass booms in the room! So there’s always room for some wonderful creativity that accommodates fantastic aesthetics, functionality, and science!


Happy Deepavali, everyone!

This is the time of the year all Hindus wait for – houses are spring cleaned weeks in advance, sweets are made, customary gifts are exchanged, etc. Grandiose is the theme of the festival’s new dresses –  people drop in at each other’s places, huge get-togethers happen for Lakshmi pooje performed by women, followed by plenty of feasts. And of course, the crackers. Now I don’t quite know what ancient history or religion has to do with cracker bursting – but we’ve all been mighty excited about it since we were kids – till many of us grew out of it.

The crackers come with a huge story behind them – of the many children forced to work with unsafe materials, working in unsafe factories, of the many fire accidents that are reported, of the many more accidents that go unreported, of the shameful salaries they get, of the heavy price they pay – risking their health, life and limb.  Now if this isn’t enough reason for people to stop using crackers, I don’t know what else could be. Surely, people who burst crackers despite knowing the abovesaid, won’t be dissuaded by the idea of noise pollution, or the distress it causes to humans, and especially to animals. My infant is already being jolted out of sleep – the cracker bursting sometimes starts earlier than the festival itself. The sound scares the living daylights out of her – it’s an explosion, for god’s sake. She wakes up screaming and crying – can’t expect her to understand “it’s merely fireworks”. Given the decent density of infants in any pocket of India – people bursting crackers should perhaps display some consideration. I will not even mention the sheer physical distress that animals must be going through – their range of hearing is much higher than ours, and they hear everything a lot louder than we do.

The number of accidents that happen at this time of the year is shocking – and many more go unreported. Children suffer burns, injuries, scars, and of course, ear injuries. So many children are rendered permanently deaf  – for your ear drum is a tiny, delicate membrane  – stretched taut. I wonder why people think the thrill of lighting crackers is worth the risk. There are toddlers and infants in half the households in India. The lifetime of suffering is not worth the thrill  – and somehow no amount of highlighting this seems to work. There’s always a fresh crop of youngsters, waiting to have their go at the crackers. There’s even some kind of graduation scheme – starting with the small ones – and when you become ‘big’, go for the loud ones. The noise levels in the proximity of such a cracker can be close to 120 -140 dB. How loud is that? Actually, it’s really hard to tell you that without resorting to swear words for accurate expression.  If you think that’s not to worry about –  the explosion is just for a brief second, hear this –  people join such things till this chain extends all around an apartment complex, and then you’ll hear this for 10 mins. Experience your ears ringing after that – and other sounds seem strangely tolerable, because your threshold of hearing just suffered a temporary shift. A few of these in succession, and your hearing will be just a little bit worse off than it was. You’ll only know in your later years.

On a more rational note, clearly, this is a modern phenomenon – this cracker bursting – Prince Rama didn’t have these in his days, I’m guessing. This is more of a social thing – one that really should be done away with.

Now, in case I’m sounding like a doomsday soothsayer, I must clarify – I love festivals myself. I’m very fond of the enthusiasm they bring, of all the sweets and savouries that go around, of all the customary meeting and greeting, of all the new clothes, of people turning up in their finery, of all the long-lost relatives we get to meet, of all the catching up, the feasting and merrymaking, and of course – the holidays! Quite the mood!  I just wish there wasn’t the firecrackers angle. There’s just plenty to enjoy without that one!

So season’s greetings everyone, have a safe festival!

The Acoustics of the DG/ Backup Power Area

Usually, acoustic engineers are never consulted for this part of the design – we all think this has only to do with the Electrical contractors for the building, and all we need are specifications on how much power backup a building needs – which determines the number of DG sets for which to provision space.

Manufacturing Specification

Even more so, because all DG sets now come with an acoustical enclosure. The mandate below, out in 2002, clearly states that DG sets must come with their own enclosure. This actually mercilessly threw a lot of people out of business – these guys used to be design and build contractors for DG set enclosures. I know one of them personally. Very depressing times for them. Now they’ve all been forced to look for livelihood elsewhere. Click on the image below for a larger view of the text. 

Excess Noise in Residential Layouts

The funny part is, this mandate does not take into account the fact that DG sets confirming to 75 dB of noise at 1 m is only good for commercial or industrial areas. Residential areas need them to be quieter than 60 dB during daytime, and 45 dB during night time. Who on earth is now responsible to fill that gap? 

Case Study: This was exactly one of the cases we handled – a fertility clinic had opened up in the heart of a residential layout. The layout is one of the most beautiful, well planned layouts –  planned by the legendary Sir. M. Vishweshwaraiah, no less! – with lovely boulevards lining one of the most beautiful, tree-lined roads in Bangalore, and the layout on both sides of it. The residents refused to put up with the noise levels  – given that Bangalore faces a lot of power cuts in summer – the DG was required to be in use for good portions of the day. The Clinic people contacted us, and we asked them to move the DG set to the terrace, build a 4-inch thick enclosure around it, leaving enough open for ventilation, but blocking line of sight from nearby houses – what they don’t see daily won’t seem obvious to complain about. :).

Heating and Ventilation Issues

Now the other problem with DG sets in mid-size to large buildings may again seem unrelated to acoustics These large buildings could be office spaces, commercial outlets or residential buildings. I know of a case where a 17-storey residential complex wasn’t able to sell the houses in the ground floor of a building, because their DG area was located in the basement below that. The noise was so deafening that while taking measurements, my colleague and I had to use sign language to indicate dimensions to the other person to write down. We couldn’t hear ourselves shout over it!

What exactly is the problem? 

Now DG sets in buildings are almost always considered a necessary evil. Nobody wants to provision the space they really need, because it means giving up precious car parking space. As a result, these are often crammed into some corner of the basement, mostly as an afterthought.

But as it stands, correct provision must be made for the emitted hot air to be vented out either by giving space around it, or by providing artificial ventilation. Merely standing around such a DG set will tell you how hot these can get, and that you will feel most comfortable nearly 2.5 metres away from it. Not in the stipulated 1m space around it. Now usually, nobody affords that kind of space around a DG set these days – which means that in the absence of a ventilation system, these sets heat up and the DG operator walks over to the set and opens the door of the enclosure to let some air in for cooling. Now what’s the purpose of the acoustical enclosure again? Here is where a heating and ventilation issue becomes an acoustical issue. 

Now basements are usually bare bones by design, and provide ample empty space and bare walls for the sound to echo and reverberate in. I’ve heard huge basements echo with large amounts of noise, annoyingly audible 3 floors up. Three hotel floors up. Acoustical engineers are then required to design secondary enclosures based on the noise reduction needed.The good part is, unless you have staff sitting in the basement, you’re okay with having decent amount of noise there.

To summarise, noise is not the primary issue, but becomes one after a few months of the building’s commisioning.  The life of the engine is affected by these design decisions. The owner of the building spends time maintaining the set, replacing parts, etc, long after the building is up. In terms of acoustics, you only need to ensure that the sound reaching your compound wall and your building interiors is within the specified limits. This is easy to do, but is best done in foresight, not in hindsight.

Festival Noise Pollution

This post was long in the making – the seeds of it sown during the recent Ganesh Chaturthi  celebrations, and now culminating in the Durga Pooja celebrations. This note is for the organizers of such festivals. Having been on both sides of the fence, I expect this post to be a balanced view.

Indians love noise. 

Let me begin by Indianizing the context – we love noise during festivals. Bustling preparations that set the whole household abuzz a week before the festival contribute majorly to the excitement – and they’re all needed to take one away from the drone of daily routine. All this has been happening for thousands of years – and frankly, not just in India – festivities involve huge preparations all over the world – and are always accompanied by noise/music/gatherings/storytelling/rituals, etc.

Festivals are ages old. So is noise. Why this hue and cry about Noise Pollution now?

So why this brouhaha about noise pollution now? What’s changed is that loudspeakers now transmit sounds over long distances, and communities are more widely spread out than they used to be.  This means there’re always a mixture of people living around you – some who don’t share that festival with you, and some who do.

What can one or two days of noise do to you anyway?

We’re talking noise 24/7 on those days.  Eight hours of exposure to 85 dB of noise can be the beginnings of permanent ear damage. And noise at a loud dandiya hall,  or near some cultural programme can exceed 100 dB on an average. In general everyone faces irritation and annoyance, students face anxiety due to their inability to concentrate, and  some exam or the other is always looming near, the older folks face raised blood pressure, the infants are  repeatedly startled out of deep sleep, and disturbed sleep makes everyone cranky – infants and adults alike.

The Legal Angle

A little bit of consideration can save you from legal action. These days people don’t take things lying down, and there are android apps available for every passer by to measure the noise levels leaving your venue.  Along with GPS mapping to pinpoint location, it’s easy to gather proof and lodge a police complaint.

Any solutions here? 

I’ve mentioned enough about what noise pollution can do to your health, so here let me only speak of the solutions we can think of.  There are strict mandates by the courts of law about acceptable noise levels in urban areas being less than 55 dB uptil 10 p.m., and less than 45 dB after 10 p.m. Organizers of the events are bound by law to adhere to these norms.  Here are some things they should do  – these will ensure

  • that you enjoy your festival while not causing physiological distress to others who don’t share your festive mood
  • that you don’t get on the wrong side of the law.

To start with,

  1. Ensure that noise levels at the boundary of your event is less than 55 dB. This is easily possible these days, and it doesn’t have to cost you an arm and a leg. Talk to an acoustical consultant. Solutions can be easier and cheaper than you think, and they may cost you less than a  twentieth of the average budget for such events.
  2. Tilt your speakers. Rock shows use line array speakers which are tilted at an angle – this ensures that the main beam of sound coming out of a speaker does not run parallel to the ground, but will surely hit the ground at some point, minimizing the direct energy leaving the area.  The reflected sound leaving the venue is easier to contain with barriers. Your sound engineer or acoustical consultant can help you with this.
  3. Cut out celebrations at 10 p.m .  Everyone needs their shut eye after a tiring day. Ask tired moms whose infants wake up 4 times an hour thanks to your mood. The solution is simply to celebrate during the day. If you can’t do that, please spend more from your budget on soundproofing. It’s not as expensive as you think, and a lot of features of the venue can be used to mitigate sound after a certain boundary.
  4. Avoid mounting horn loudspeakers on streetlamp poles for half a mile on each side. In other words, there’s no need to tell the whole town about your celebrations. Use posters/hoardings to publicize, if you have to. Keep all your loudspeakers within your venue.
  5. Use ear plugs yourself. Quite honestly, your ears aren’t made of sterner stuff  compared to those who get disturbed by noise at a distance.  Before you find out the wrong way, please do things to protect your hearing. You will be able to dance quite well to the music despite ear plugs in your ear – they only reduce the direct sound hitting your ear. Try it.

So is it really possible to contain noise in such venues? 

The simple answer is yes. Distance does a great deal to help attenuate, so if the venue is large, it is more easily possible to contain sound at the edges. I was once posed with a client’s requirement – they wanted me to think of some kind of enclosure that tests audio setups for live sound. So this enclosure is to have about 50 dB of sound on the outside, while the inside sound levels would be about 120 dB. The catch is, because this enclosure tests live sounds, it has to be completely modular – one should be able to dismantle, transport, and assemble it.  Now THAT’s a difficult project. Only heavy mass can block sound over short distances.

So, controlling noise levels from leaving a fixed area meant for large gatherings is decently possible.

Acoustics for Speech and Hearing Institutes

I’ve only just started freelancing on my own. Unlike the initial  romanticised impression of acoustics being the perfect mix of music, maths and physics, I really spend most of my day listening to noise :). So I thought I should get my hearing tested for two reasons:

  1. To have a point of reference for a ‘before’ and ‘after’ scenario of my hearing sensitivity.
  2. To understand what frequencies I am sensitive to, and any hearing losses I may have for other frequencies – so that I can accurately tune listening spaces.

I went to this institute near my place and found out two things that didn’t suit my needs.

  1. I could hear road noise very clearly inside their listening room! This is past 3 doors, no less – the entrance door, the door to the audiologist’s room, and the door of the listening booth.
  2. They test only 5 frequencies from 250 Hz to 8 kHz, because this is primarily for old people to hear speech.  For my purpose of tuning spaces for music, I need to be tested for a much wider range – 50 Hz to 18 kHz.

Anyway, I went ahead and turns out my hearing is normal, but I suspect it won’t stay so for long. I am a tad sensitive to vocal high pitches – the Lata Mangeshkar types – playing those at normal volumes can grate on my ears. But I did have difficulty in listening to low pitches – the 250 Hz thing. This would’ve been critical information for me to have found out – except that I will have to take it with a pinch of salt, pending more accurate tests. There was plenty of low noise infiltration through the doors, and I could hear them despite the on-ear headphone.

Anyway, the point is, that critical spaces such as these must not have any type of noise coming in. They had even used thermocol for acoustical isolation. Thermocol, styrofoam are easily and cheaply available, but they are not acoustical materials at all – they can at best be used for impact isolation.  There was also some masking effect happening due to road noise intrusion. I could clearly tell the sound of an auto, a bike, a bus, and some local vegetable vendor hawking at a loud voice.  This is also because the glazing they had used was rather thin. It is critical for listening booths to have glazing because they are to be closed, and the only way for the audiologist to know that you are able to hear a certain test frequency, is when you raise your hand. They have to be able to see you. Glazing itself is not a problem, but the right thickness must be used. Also for such applications, either in-ear earphones, or supra-aural earphones must be used. On-ear headphones are not very effective for blocking out sound.

These and many other defects can be solved right at the design stage.  Eventually, the kind of hearing aids that are prescribed are primarily influenced by the extent of the patient’s hearing loss, and the budget.  The first factor – the extent of the patient’s hearing loss can be accurately gauged if external interference is zero. In this case, it is critical to avoid masking effects.

The right technical advice will take into not just that, but also the hum of your HVAC, the type of earphones you must use, the influence of nearby buildings and their DG sets, etc.  It should also prescribe materials from a rough-use point of view (for instance, the rubber linings of the door had peeled off – leading to a compromise in sound isolation). For a place primarily meant for accurate testing of hearing loss, the noise constraints posed by the location can be easily overcome with correct acoustical diagnosis, testing and recommendation.

Acoustics for Schools and Colleges

I’m going to structure this post in an FAQ format.

Q: We never had a problem with acoustics when we were growing up. Despite not having acoustically treated classrooms, we heard our teachers just fine.  Why worry about classroom acoustics now?

Educational Institutes earlier did not have a few issues that they face now. Here’s what’s changed:

  • Diminishing Playgrounds: The school I studied in had place for football, basketball, tennis, garden, swings for children, a huge auditorium, and even a mini-zoo. The classrooms were in a central building, separated by the main roads by these sports areas, and the school as such was located in a residential area. In contrast, these days, with land prices shooting through the roof, there are plenty of schools in Bangalore with no playgrounds, let alone garden spaces. They either just don’t have one, or they use a municipal ground nearby as their own. I’ve taught in a 30ft long class, at the end of which was 4 ft of external corridor, and then (gasp!) the main road. With the last benchers being 4 feet away from traffic, and 30 ft away from the voice of their teacher, I wonder what they managed to learn. They strained their ears all day above the muffling effect of traffic noise.
  • Road Traffic Noise: The above problem is compounded by the fact that roads are no longer quiet. There is more traffic, more honking, and louder horns than ever.
  • Air Traffic Noise: If anything, air traffic has increased in the 20-odd year span that has passed since I went to high school. All the big cities, some of the smaller cities have all got airports. I’ve sat in the most beautiful lung space in Bangalore – the Lalbagh – and watched 15 flights go above my head in one hour. It’s a bigger problem than we think.
  • Changing Interiors Trends:  These days, the interiors are all sleek, with vitrified tiles commonly in use,  with tables and chairs also having sleeker, smoother finishes. These surfaces reflect much more than materials that were used in older buildings.

Q: So what problems (that I need to worry about) do these building environments cause?

Reverberation:  This is a double edged sword. Too much of it, and the room sounds forever noisy, noise just doesn’t die down, the mood is abuzz, instead of calm. The room makes some voices stand out more than others.  Too little of reverberation, and the room sounds dead. Everyone tends to strain to speak louder.  In both cases, at least the teacher ends up with a raspy voice at the end of the day. It doesn’t just stop with throat irritation ( that persists even during non-teaching hours).  When you’re in a chaotic environment, your heart rate’s always higher. This means your body doesn’t feel calm. You lose quality of life right there, let’s not even talk about after-hours fatigue. Teaching ceases to be enjoyable right then.

Poor audibility : Teachers often have to shout to be heard over the ambient background noise. This volume is often too loud for the front benchers, and usually not enough for the back benchers – leading them to be distracted and disengaged. Teachers are all too familiar with the buzz of conversation in the back benches, when they’re distracted.

Extra boominess : In the same room, some pitches sound very loud, and some pitches sound very soft.  Male teachers with low pitched voices will often find that, there are sometimes spots in the room where their voice sounds too loud, or faint.

Low speech intelligibility: You hear the teacher’s voice booming around you, but you can’t make out the words very clearly. There’s enough research out there for you to look up, and that’ll make you realize that there are schools where students miss out on close to 50% of the speech.  There’s a nervous irritability that sets in when students are not able to understand despite their focus.

Q: This is tricky ground. You could easily be talking through your hat. Is there any way to know for sure that learning is impeded by poor acoustics? Is there proof?

It is true that the concentration ability of all students is not the same – there are always those who concentrate well, and those who get distracted easily. However, organized studies have been conducted – some for as long as three years – to obtain unbiased proof of the effect of bad acoustics on learning – all other factors remaining the same. There is a genuine link because the act of ignoring the existence of a noise source also uses up cognitive power.  A few if them are listed below for those interested. I will not go into explaining what each one says, because these only substantiate what I’m saying.

  1. : This study by the BBC conducted as early as 1999 was conducted for nearly three years.
  2. : This study speaks of vocal strain,  classroom acoustics, and substantiates it with measurements conducted before and after acoustical treatment.
  4. : This last one contains a set of articles regarding current standards recommendations.

Q: How can acoustical treatment help?

In places where the spoken word is the main purpose, acoustical treatment should be considered as important as other aspects of building design. But to keep things short, the improved hearing experience will surely bring benefits – some obvious, and some intangible but important nevertheless.

  • Less vocal and physical strain, more quality of life for teachers.
  • Better comprehension, less disengagement, more active participation
  • Better behaviour due to less frustration. The social effect is the most important, and the least readily tangible.

Q: I don’t understand acoustics. What does a 10dB loss mean? Can I hear some examples please?

The links below have sound samples that tell you what some classrooms sound like, and what they should sound like.

A wonderful talk by Prof. Trevor Cox, speaking of what just a 10 dB reduction in noise levels can do for your understanding.

Another talk by Julian Treasure, discussing the academic, physiological, and social implications of better acoustics in classrooms.

The cost implications of treating a room is surely smaller than the huge profits that many schools in Bangalore rake in. The benefits are huge. I will post another article on the kind of treatment required for speech enhancement. For now I hope people reading this are at least aware that acoustical treatment can significantly enhance the listening experience at places that exist entirely for this purpose.

A quiet environment allows the mind to freely explore ideas, thoughts, and form quirky connections in the head. A noisy environment disturbs not only the mind, but also the body.