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!


Thank You For The Music: A Deeper Look At Resonance

We’ve all gone through days when the facts suddenly become too much to handle. That important link between gathering facts and processing them seems to be some kind of bottleneck. That’s when I need to shut out the physical world. I invariably resort to music. It is my first weapon of choice for a mood change.

Why does music make us happy?

Now I’m trying to see if I’m just pleasing my auditory senses here, or if the relaxation happens because of some other factor. True, some good sounds that hold you in rapt attention can take your mind off the reality you just faced. So temporarily, your energies are devoted to something pleasant. Which means, there was something about the real world that made you tired, de-energized, and there’s something about some well harmonized sounds, that ease out your tiredness, and relax those constricted muscles. This could be natural – because music is by definition a collection of sounds that are harmonically related to each other, and even with distortion, can sound quite pleasant.

What about songs that can make you hit the roof with excitement?

That happens when there’s visible gaining of energy … somewhere some resource is being unleashed in your body and as you get absorbed in the rhythm, melody ( or whatever it is you look for in a song)… and as the intensity of the song picks up, you feel your energies returning full strength, and these keep increasing till the end of the song, leaving you on a high.
This intensity of the song, causes your own positive energies to come out and spread themselves on you. This visible gain of energy is worth looking at. It probably doesn’t make sense to rationally analyse these energy transactions, because the very idea of a clinical analysis separates you from that source, but here’s a go at it. Let’s start with the clinical definition of resonance from wikipedia:

In physicsresonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. Frequencies at which the response amplitude is a relative maximum are known as the system’s resonant frequencies, or resonance frequencies. At these frequencies, even small periodic driving forces can produce large amplitude oscillations, because the system stores vibrational energy.

Naada Brahma – The Universe is Vibration

The first idea I’d like to talk about is the Sanskrit phrase – Naada Brahma -which means, the universe is vibration. So you, me, the laptop, the dog, the bridge, the building, are all vibrating bodies. Now we know that this is true at least of structures – structural engineers calculate resonant frequencies carefully. Not doing so results in disasters such as the Tacoma Narrows Bridge – where side winds set up vibrations approaching the resonant frequency of the bridge – and this turned into a self-feeding mechanism that resulted in the bridge swinging wildly with larger and larger amplitude, till it broke at the center. Here’s a video:

Now if seemingly rigid structures can have resonating frequencies, why not the rest of the world? The songs we listen to are all a combination of instrument vibrations, so the song must have its resonant frequency? What about us? Are we resonant ? On at least some tangible level, yes. Some people we ” resonate” best with, are our close friends. We’re on the same “frequency” with them.  Others cancel out our fond beliefs, so we tend to stay away from the likes.  And so, there are songs we like,and songs we don’t. There are people we like, and people we don’t.  “It’s a vibe thing” …

Least Resistance

At this resonant frequency, the two bodies in question have the least amount of resistance between them. And so there is a maximum transfer of energy – no energy is lost in any kind of impedance/resistance.

Manodharma – Expressing the Inner Energy

Now the other idea about why we suddenly gain energy from some kinds of music.

The song is a collaborative effort of a few people who got together and established contact with their inner energies and instincts and expressed whatever they felt then. It could’ve been their rational minds exploring a technique or a scale, or it could’ve been their feelings taking them up and down the scale. Either way, their rational mind or their emotions, contact with something inside has to be established before their skill can express it. Their skill can only express it. The word for this “something inside” is Manodharma . Carnatic musicians use this word to describe an artist’s ability to express themselves completely – this part of the concert is a mix of skill, intuition, feelings, rational intellect. Wikipedia says ” Manodharma plays such a significant role that a capable artiste may never render a raga the same way twice.” There’s a fixed part of a carnatic concert dedicated to this, while the rest of the concert rendering follows rigid rules of structure.

So when I listen to bands that take off on lovely riffs or ones like Shakti, where each person is spontaneously exploring their domain within the framework of the song, I feel that my reaching a high has as much to do with seeing this contact they’ve established with their inner selves, as with appreciating their skillfulness.

I don’t know yet, but on some level, my inner peace gets unleashed, the frown vanishes, the set jaw relaxes, the gaze softens. Some songs build up on intensity instead of just soothing their way till the end. Then I can actually feel my toes and fingers bubbling with energy towards the end. After these visible energy changes, I feel like I just shrugged off those silly inane worries.

When I listen to a classical piece, I can see the singer so much in contact with the feel of the raaga, and yet retaining judgement to express skill within its framework. In fact, our ancestors have classified raagas so accurately according to the feeling they induce, that one wonders how they gauged all this rationally – it really deserves a separate post. Maybe it wasn’t all rational.  Maybe it’s not just music. Maybe it’s directly rejuvenating to see anyone establish a moment’s connection. Music is more instantaneous to me because I posses some basic skill.

But I’d be wrong if I tried to limit all my happy moments to music. Resonance happens with us on many levels. 

It may be a piece of art, it may be a deed of kindness, or it may be a program that worked after you spent all your energy on it trying to make it work, or just something you cooked that turned out well. If we only took time to take a step backwards for just a second, and savour that moment – the very next moment, you’re already smiling.

Music, art, work, anything… they’re all reflective of human thinking, and of human transcendance, and are a direct expression of the vibrational energy that exists around us. Regardless of what moves you –  please take a moment off to step aside and shake hands with it.