Acoustics for Auditorium Spaces

This type of space is apparently the bread and butter for most acousticians – with most non-acousticians being aware of the necessity of acoustical treatment in such spaces. Other spaces are work for us too, but usually only after some problem persists beyond the ‘experienced’ trials of the construction period. Auditoria also suffer from the fact that most are over-treated for music, but just about right for speech. Here are typical acoustical issues that these spaces face.

Large Reverberation Times and Speech Intelligibility 

Reverberation is the fundamental problem that all Paanchvi Pass se Tez people are aware of. You cannot get this wrong and get others right. But while getting this right does eliminate the largest of issues, there are many issues it does not solve. I have worked on projects where a previous ‘consultant’ had set only the reverberation time criteria for spaces, and I had to fight tooth and nail  and evidence and auralization and case studies to prove that speech transmissibility depends on other factors too – which they hadn’t bothered to address. We settled for an inbetween solution – where I gave them both sets of data – for speech intelligibility as well as their beloved Reverberation (for them to do whatever they pleased with the latter).

I am amazed at how many times the Royal Albert Hall is brought up in initial discussions for such large spaces. At the time it was commissioned, it had far too much volume for its seating capacity and the echo was so bad that it was known as the only place where a british composer could be sure of hearing his work twice 😀 (reference available 😛 ). Later a  number of clouds were hung from the ceiling to provide better early reflections and that fixed it to a large extent.

Getting good early reflections is vital to achieving good acoustics in large spaces. The traditional RT60 analysis is based on some assumptions that don’t necessarily hold good in all spaces.  Also there is a growing crowd of fellows who think a simulation software is all that is needed to get the acoustics right. Yes, these help a lot, but knowing what data is ‘real’ and what part of it is ‘extrapolated‘ is important. I’ve known people who compare two such programs and proclaim that one gives you data down to 63 Hz. May I please add that you might want to take that with a pinch of salt – most diffuse field assumptions are not true at 63 Hz, and so it is tricky to calculate even standard NRC data for that frequency band. Of course, we do measure the response of the LF absorbers we design, but the test conditions are not those typical of measuring NRC data for others. On closer questioning as to how they even managed to procure NRC test data for that frequency band , the program evangelist revealed that they assume that if something provides x NRC at 125, it should give you at least that much at 63 Hz.  So this is added to the overall frequency response to make it look ‘more complete’.

This is just one example – it is vital to understand the limitations of the software. For low frequency analysis, some kind of meshing software will work much better than ray tracing.  Of course, bear in mind that LF issues are much more pronounced in smaller spaces, so with larger volumes, there’s a decent chance we’ll get away with not doing too much to tame the LF. This doesn’t mean we leave it unattended – I’ve seen metro stations  (Delhi) and a 2800-seater auditorium that have low speech intelligibility despite having decent RT60. Fixing the LF in calculated measures will help in such cases.

Also, in many cases, the reverberation values of the spaces are calculated in what is sometimes mathematically more efficient and may not truly model the physical process of sound decay in that scenario.  Multiplying a T10 by 6, or a T20 by 3, or a T30 by 2 may not yield exact results. The actual RT60 could be slightly different. Understanding the physical process and mathematical algorithms and the approximations made are vital to making realistic sense of the data thrown out by these programs.  There’s also another factor – scattering. Calculating with and without scattering co-efficients can actually make a lot of difference. We have to work within limitations of the amount of scattering data that is tested and available.

Background Noise

This depends on factors such as the HVAC equipment and layout, ambient traffic noise, number of windows and their positioning, and in some cases, general MEP equipment nearabouts.  I’ve seen auditoria where an AHU was suspended above the false ceiling of a greenroom – right next to the stage, and there was no door between the two areas. There are other spaces where the green room was only 6 feet away from the compound wall of the venue, adjoining a state highway. Traffic noise freely flowed into the green room and was picked up by the microphones. Our very own Chowdaiah hall here has duct cross-talk issues (sound from music classes in the adjacent rooms comes through to the stage) and also has rain noise infiltration . To Bangalore’s luck, we get rains sharp at 5 in the evening during monsoon – just when all evening events start.

Windows

Now apart from letting in noise, there’s a larger issue – most school auditoria will typically be built like a huge wedding choultry – with ample natural light coming in so that they save on electricity. Acoustically, we then have to look at different scenarios – when windows are shut the reverberation is very high, when they are open the reverberation time looks good, etc. An auditorium I worked on had vehicle parking stands closeby, and all those shelters had corrugated sheet metal roof – and this place is on the coastal belt – it rains like mad. The surface area of the shelter is enough to create a fairly loud sound when rain falls.  Sometimes the number of windows is so high ( for example a triple height auditorium with three rows of windows) that our acoustical estimates vary rather widely between the two extremes – and once commissioned, we have no control over many windows will be opened or closed at any time.

Also the other condition these windows create is that of perfect planar reflections – leading to flutter and ringing. Most often, due to symmetric design, windows face each other.  No, curtains don’t solve all issues, although they might be a better option compared to not doing anything at all! The reflectogram has to be carefully studied to understand these aspects.

Coupled Spaces

These significantly affect the speech transmissibility, and it gets very tricky to calculate even reverberation times.  This is especially true of spaces with traditional architecture  – churches and mosques.  In India, many wedding halls and school auditoria have corridors on the sides – these do not form a part of the audience areas, but are coupled with the existing volume.  The effect of the double-slope decay contributed by such spaces can be fairly significant.

Shape of the space(!) 

Uh huh…I’ve worked on one auditorium that was so perfectly fan-shaped that we ONLY had to solve reverberation issues there – the shape took care of all other things! The same architects were, however, also coming up with a completely circular space elsewhere. I was lost for words.  Yes, we can do things to fix that to a good extent but a lot of treatment is then required to just correct issues that are thrown up only due to the shape of the space. Some issues can never entirely be eliminated in such shapes.

Multipurpose Halls

There’s that word again. But really, no space is exclusively optimised for speech – with the current real estate scenario,  and we are very realistic about that.  The extremes of expectations sometimes vary quite a bit – from hosting a world-class basketball court and badminton court, to holding TEDx talks in the same space. Variable acoustics is the key here. There’s no need to buy expensive panels that can be overturned  to increase absorption. It’s far easier and cheaper to construct such panels and most schools have enough manpower to get these mounted or dismantled as required.

To conclude, large spaces typically pose challenges with respect to reverberation, and acoustical simulations of  such spaces can provide very good predictions of the end results post construction.  However a lot needs to be understood about the assumptions, the test conditions, the limitations and the error margins and material data of such software programs.  Empirically or superficially  analysing such data could prove to be risky. Acoustics is a young science, but we seem to have a massive set of failed examples to refer to. Those are invaluable in the insight they provide.  Getting the acoustics of large spaces right is tricky, especially with the amount of straddling across various intended usages that we have to do, but once done right, it is immensely satisfying to see the design take shape as a space that provides warmth, clarity, brilliance, intimacy and envelopment in the desired proportions.

 

 

 

 

 

 

 

 

 

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Acoustics for Clubs and Lounges – 2

Great. Now that we’ve largely taken care of soundproofing in the previous post, let’s look at what happens in the interiors.

All Glass 

Glass is something we can’t avoid these days, and the challenge is to ensure that the sound field in a room is sufficiently diffuse, despite perfect planar reflections from large panes of glass all around you. This poses trouble even for the mids and highs, let alone the LF.  How do you introduce time and phase shifts? How do you reduce the spot intensity of standing waves forming peaks and nulls at the same spots ALL the time? Well, clever options are possible if you lay down the fundamentals of the concept/solution to the architect, and let them play with it. They ARE the creative of the species. In Mumbai, a lot of old industrial sheds have been successfully converted into music lounges – despite the theoretical odds.

Mixed Usage

Here’s a very generic scheme of what sound should sound like, for various usages:

Frequency	Movies	Live Music	Gaming
Bass	Loud, but not boomy	Tight	Loud and Boomy
Mids	Short	Long, resonant	Short
Highs	Dead	Long,	Short

Now lounges have another category    – DJ music. The kind of absorption you need for these scenarios is really different, but we always have to strike a balance. There is always a mixed usage. The kind of bass you need for DJ music is thumping, compared to the kind of tight bass you need for say, smooth jazz. Actually, for those who know their music, within EDM ( Electronic Dance Music), there are so many sub-genres each of which have a typical characteristic feel – all contributed to by the balance of highs, mids and lows.

Now while it’s great to experience this variety, at the design level it is not really possible to alter a room’s response to suit different scenarios. So broad generalizations are made, keeping in mind the primary use, the secondary use, etc. Sometimes the extremes are too far away to bridge – such as one project I’m pitching for where I will need to design for typical lounge music, DJ music, and the space also doubles up as an exhibition area, or ( hold your breath) – a conference room!  The ambience for an exhibition area must be a quiet one  – low noise, piped music, etc, and for speech – deadly quiet. HVAC hum, etc are factors to monitor here. Now for the volume of the space, speech is going to sound terrible if music is to sound awesome. Variable acoustics is the key here. There will have to be additional absorption brought in when there is a speech event going on. The design must be modular, easy to assemble and move, and sturdy.

Such a situation also requires variable sound systems. You can’t be playing piped music through a line array meant for live music. Sound system engineering is also critical for soundproofing. Choice must be made between having a distributed system or a line array-like system. Distributed systems must be chosen to ensure their coverage isn’t much more than needed – to avoid excess sound pressure at the walls. Compared to distributed systems, for the same power configuration, a line array system will beam all energy along the main axis – while keeping smaller amounts of energy in the side lobes. This makes it suitable for long halls, marginally/significantly reducing soundproofing needs for side walls, but surely increasing the soundproofing requirement for the opposite wall. However, low frequency response is nearly similar to that of a distributed system. So soundproofing requirements for LF stays the same.

Mixed usade presents another issue in that seating plays a very important role in acoustics, and we are unable to take that into account for such cases. Seating accounts for a significant absorption, and so does the crowd – we design for 2/3rds occupancy typically. If furniture is going to be modular, to be shifted in and out for various scenarios, our calculations have to buffer for that. Also, the place could have 150 people for a DJ session, and only 25 for an exhibition. The challenge lies in making intelligent estimates, and in knowing the broad ranges of parameters within which these estimates are true.

Concluding each such article leaves me excited about the variety of cases we get to solve in the ever-evolving melting pots that our cities have become.

 

On Studying Acoustics

I’ve been often asked these questions by a host of people, and considering most of these conversations run into at least an hour if any justice is to be done, I thought writing down the basic information would be useful. This is by no means exhaustive, just a starting point.

Scope of Acoustics 

The most beautiful thing about acoustics is that it is a very multidisciplinary subject. There are fields coming together at all levels – pure math or pure physics, statistics ( perceptual audio and psychoacoustics), electronic engineering ( transducer design – loudspeakers and microphones), mechanical engineering ( noise, vibration and harshness  – NVH), and not to mention music ( tuning spaces for music, musical acoustics etc).  The field that I’m working in is called Architectural Acoustics – I work with architects and builders to design spaces for optimal acoustics and soundproofing. Let’s cover these one by one.

• Psychoacoustics/Perceptual Audio : This is more research oriented,  and there is very little work being carried out in India on this. ITC Sangeeth Research Academy is one place that does regular research work on this. Audio manufacturers  and mobile phone manufacterers are also interested in this field, but to my knowledge there’s only sales and marketing going on here. Philips has some acoustics-related work here in their product development facility.
• Electro-acoustics – Commercial/Private Sound System Design: This field has broad applications, and the two companies that actually do product development in India are Sonodyne and good ol’ Ahuja. Most others have manufacturing lines in China or elsewhere and at best hire software engineers to design computer interfaces here. The significant bit is always sales and marketing, and execution – which involves project management, client account management, design, installation, testing and commissioning.
• ElectroAcoustics – Microphones, etc: This throws up a whole lot of mobile phone manufacturers as potential employers.
• Electro-Acoustics –DIY: This aspect is something that needs highlighting. I know people with fantastic talent in this area. There are plenty of projects to execute if you know the indispensable art of negotiating, project management, and marketing. There is, of course, stiff challenge from the branded products that are sold by equally agressive AV vendors who also offer automation, but there’s always place for talent.
• Mechanical Engineering: Knowledge in this field will give you an edge when working on industrial acoustics projects. The scale of problem solving is stupendous, as is the cost of basic transducers you need for vibration measurement. I know firms that deal with such a huge variety of problems – from the nanoscale (hearing aid devices) to ocean acoustics. Basic knowledge of finite element modeling, boundary element modeling, meshing etc is vital, and there is investment in terms of procuring some relevant software. Other applications are aero-acoustics, and automotive NVH analysis. With Boeing and plenty of aero-acoustics firms setting up engineering establishments in India now, and with automotive firms moving similar research to India, there’s a big thumbs up for this side of acoustics.
• Music: Now I started out with this, and my basic love of the sciences. It turns out that the place where you experience maximum music is in live sound acoustics, and electro acoustics, where you test loudspeakers, or even in perceptual acoustics – where you may be playing music to check its effects, etc. Not so in the field I’m in! Now I know a lot of sound engineers who can just listen to sound and and tell you exactly what the problem frequencies could be. Sound engineering, however is different from the study of acoustics, and they have a different skill set. It is important not to mix the concept of music production and sound engineering with the study of acoustics. There is a mild overlap, but the rest of it is quite divergent.
• Architectural Acoustics: I spend some part of my week taking noise measurements ( – irritating traffic, deafening train horns, machinery noise, stuff that grates on your years), and many of them at night hours. In the other part of the week when I’m on a desk, I look at dry numbers, excel sheets, formulae, impulse responses, CAD drawings, software models etc.It’s REALLY dry – the only music you hear is that on your ipod if you can work side by side – so getting into this profession because of your love for music is a very overrated idea. I do design spaces for sound, but time management tells me that I have to be more interested in running swept sines or MLS sequences, or blasting white or pink noise in a place instead of joblessly hanging around on a site listening to music!   You need to enjoy calculations and analysis to be able to hang around in this field long enough. I’ve climbed 16 storeys of of a building in my third month of pregnancy, assessing noise issues floor by floor, with no place to sit, and debris strewn everywhere (construction sites build lifts after EVERYTHING else is done. The other option was to use a precarious-looking service lift outside the building). Of course, I was all excited and had no complaints, but my folks freaked out, as did my doctor. Long hours of standing on sites is a given. This is true of any construction-related field.
• Environmental Acoustics: Again, overlaps with Architectural Acoustics and Industrial Acoustics sometimes when it comes to soundproofing projects. Building noise control is increasingly important as residential and commercial zones are overlapping in growing cities.
• Naval/Ocean Acoustics: This is for the seriously technically inclined. Needless to say, most work locations will be located on coastlines. You can’t choose to live in a place, should you make this choice.

Scope of Working in India

This deserves a first mention because people ask me this before they’ve even thought about why they wish to work on acoustics, and rightly so. The field is still nascent in India.

Acoustical Design is a relatively niche field in India, but things have changed significantly in the last five years alone. When I studied my course, I was still comforted by the fact that I had experience in the IT industry and could always get back to it if I wanted to.  Now there are paid jobs available, and of course the option to do freelance consulting is always there. I chose the consultancy option because it gives me the flexibility I need with a 2 year old toddler.

Salaried Jobs:   A lot of audio video companies are looking for an in-house acoustical designer, and there are acoustical product vendors who also need in-house design services before they can quote for a project – so these are typically the kinds of salaried posts people can expect.

Consultancy: Technical skills are about 20 % of what you need to run your own business. Business skills are equally important. Consultancy has its ups and downs – you sometimes have to spend time recovering money from delayed payments when you’d rather be doing fundoo design, and it can get difficult to plan your finances if you don’t know how to hold your own. Work always needs to be done ASAP, but there are always processes for payments.  Construction itself is a rather unpredictable area – there are unforseen delays and projects rarely get done in time. It takes some getting used to. Also, in the Indian mindset, people like to pay for tangible things – such as products, or installation – it’s rare to find someone who gives importance to design.  But all this takes some getting used to. A few projects down the line, you learn to draw up your set of rules. It is fair to say that while there are enough freeloaders on this planet, there also nice people who think other people’s labour is to be paid for. You learn to tell the difference, but it’s always a trial and error method.

There is also the issue of managing time, especially for women in the Indian context. I’m incredibly lucky to have a fantasic support system, but not every one else can be so fortunate, and this profession has its share of multiple projects landing up together – and this entails nightouts. It also has its share of multiple projects being in a state of execution and your support being sparingly needed. It’s important to stay productive all the time.

Most acoustical consultants I know are not into pure consultancy. I know only a handful ( including myself), who rely entirely on doing only design/problem solving. I couldn’t have done this without my family supporting me till I reached steady levels. One person I know who does pure consultancy( and work with) also works half time with a U.S firm, and that’s his steady source of income. Most others tend to take on turnkey installations ( which means they charge for project management, have margins on materials, etc). Others have ventured into offering a complete auditorium package –  lighting, audio and video, along with acoustical design AND installation, and even audio renting. These are the qualified ones.

While I am a believer of learning on the job, the bulk of acoustical consultants in India are those who can’t tell absorption from isolation. Simply because there is no opportunity to study the science here. Most are forced to offer acoustics as a freebie to clients, while selling either wall panelling, or AV products.  I can count on my fingertips the number of acoustical consultants here who are qualified, who are independent ( do not take commission for recommending products or for vendor referrals), and who do only pure acoustical consultancy. It’s a big decision to take – the turnover is bigger if you take on bigger jobs – simple. Turnkey Interior vendors do business worth crores – it is a very tempting proposition.  As problem solvers, independant acoustical consultants cannot quote their fees as a percentage of the project cost, or on a per-square foot basis for ethical reasons. Instead, we quote for our expertise and time. More on this in a separate page on Independent Consulting.

The upside is that consultancy allows you to work at your own pace like nothing else does. I know how important that can be – on days when the toddler falls sick, or when the babysitter falls sick. I restrict travelling on site visits to two days a week – which helps to ensure that I get uninterrupted periods of time during the other days to get important design work done. Once work starts flowing in, days and nights can get merged into one. Growth is required – you will need assistants for CAD, for site visits, for marketing, report writing, software modeling, measurements, etc.  But I have yet to see a firm that is larger than 6 people.  I haven’t done any marketing so far, but have required help for all others aspects I just outlined. As with any business, you need to ensure you’re covered for a year of regular and random expenses so that you don’t fret or get a panic attack when payments are delayed – as they inevitably will be.

Studying Acoustics in India

In India, the options are fairly limited. A couple of IITs and IISc have some courses in technical acoustics, but I’m not sure of what the entrance criteria is.  Institute of Acoustics has started a chapter in India, and they offer diplomas, but I’m not sure of any further details. I had no choice but to go abroad.

Studying Acoustics abroad

Studying abroad is a great idea. It’s also the rich experience of interacting with people from very diverse backgrounds that helps you become a lot less judgemental, than cocooned home birds. However, one needs to plan finances very carefully before embarking on such a journey. It can get difficult to start out on your own while having an education loan EMI to take care of. I was lucky to get away with 8 % – that doesn’t happen anymore – it’s now at 11 or 12 % – that can get crazy. This made sense earlier when the job markets abroad were good, and acoustics being a rare field, the visa or residentship application for this comes under the category of highly skilled migrant workers in most places. With job markets not doing so good in EU and the US, construction takes a nose dive, and with it, so does construction-related work.  So it makes sense to study abroad only if you are able to manage the finances well.  With my frugal lifestyle ( studying acoustics will usually not leave you with much time to have a life, as the course tutors themselves had advised us 🙂  ), a lucky 8 % interest on loan, and the fact that I came back home after finishing my coursework and completed my thesis from here, supported throughout by parents, husband, parents-in-law – I ensured that my loan was only 10 lakhs – course fees, flight tickets, living expenses, combined. This still means an EMI of 17k every month. I knew many even back then whose lifestyles just couldn’t be brought down to less and they had serious issues managing their finances.

At the current rate of interest, and with rents, course fees, etc on their way up since I went there last, I’d say the monthly EMI will easily be around 25-30k a month. Think very carefully about this. Most loans now offer 10 year repayments also, though 7 years is the norm.  To a lot of people, studying abroad makes sense if you can work abroad and make some money for a few years before thinking of coming back to India. The equation is no longer true – due to various factors – general down turn, etc,   it’s not as easy to find jobs as it used to be, stricter immigration laws, significant taxation, higher living expenses to start with, etc.

I must point out that it is easier to get a salaried job abroad than in India – because there the building norms are very clear on the certifications and compliances, and more importantly – they are strictly followed and enforced. Here there is no such thing. People worry about soundproofing only when they are in danger of having their place shut down due to complaints. But even there, acousticians lament that the field is very rare and many just don’t even know such a thing exists. But for sure, organized work is much more easily available there than in India.

Courses Abroad 

I studied at Univ of Salford, and we were privileged to be interacting with the best minds in the field. The course gives a fantastic introduction to the field and we were left in awe at the end of most classes. The course is very intensive and you’d be left with nearly no time to have a part time job, unless you’re a genius and can comprehend lessons in half the time it takes the rest of us to grasp concepts. A strong numeric background is required. You could opt for the audio acoustics module if you’re good with electronics, or the environmental noise modules if you’re interested in noise control. These are two modules each, and the other six modules stay the same. For most current information, please visit the website of the university.

There are many other universities in US, EU, and Australia.

To conclude, the field is nascent in India, and that is both a good and a bad thing, depending how lofty your aims are. Getting into acoustics is a tougher decision to take compared to thinking of other mainstream areas, and this decision takes a good amount a planning. I am personally driven by the joy of experiencing how good a place sounds, but that alone is not enough to keep up a healthy tempo. Though the field is related to music, experiencing music is not really a part of the work – experiencing noise and balloon bursts is :).  The romantic illusion that led me to this was that this is the perfect amalgam of my interests in music and sciences. I’d like to burst any such bubble right now. 🙂

Things have looked up significantly in the last 5-6 years and there are now firms offering paid jobs in the field for those unwilling/unable to take a plunge into consultancy. I cannot emphasize enough on how unorganized the construction industry is in India, and there are no standards on processes and payments.  It takes serious passion some major family support to keep going forward. To work in architectural acoustics, one must surely have a sense of music, but can do just fine without it, as long as you understand material science and wave propagation well.   Also, consulting works well for women, and it feels good to see things taking shape and the money rolling in – for much less the time you’d spend in a regular 8 to 8 ( 9 to 5 doesn’t really happen anymore, does it). For those willing to endure the rest of what freelancing/pure consultancy entails, it can be a rewarding experience to see a building come up from out of nothing and to hear it sound the way you designed it.

Discernment

Now this deserves a mention because of the variation that exists here.  I’ve met people who’ve have told me that they’ve never done acoustical treatment at any place they’ve worked in, and their systems have always sounded excellent, and that the software we acousticians use to validate our estimates is only cosmetic, and is only for reporting purposes. I have no issues with their fond opinion. I only have an issue with the notion that it could be an absolute ‘opinion’.

The point is, satisfaction is a classic case of roti kapda aur makaan – how much “more” you want depends on you, and there are no absolute standards. Every construction worker who passes by in front of my house has a pocket radio blaring sickly-sweet bollywood songs from the 90s ( for some reason, their musical taste is stuck in that era – I mean ALL of them – nothing before or after that!). You should come and see how happy those workers are, singing along. I should just start with myself – a pair of Creative 2.1 speakers with a rented computer can arguably contend for one in top five slots for best memories of college days –  I thought the world of them, and have spent wonderful years listening for HOURS daily. What I’m trying to say is that not everyone shares a particular level of discernment.

The field of subjective testing is a very interesting one, and amateur enthusiasts are eagerly getting into it. The field is closely related to Psychoacoustics, and subjective testing methodologies ( AB, Blind AB, etc). It’s a very interdisciplinary subject – it starts with the wonder of biology, and ends up on statistics. There are broad definitions of terms describing music, and many would concur with those, but only when the sample is played in contrast to something that doesn’t fit the definition. I should write another post on the terminology used to describe audio, and what they mean on a physical level. Audiophiles need to understand that for economical reasons, the vast majority of the population is very happy with commercial “low-end” systems.   We will instead try to see what the “discerning” ear looks for. Turns out, there’s a rather huge variation here as well.

Obviously, hisses and crackles and clip sounds are not acceptable. Assuming clear audio quality and no system-induced distortion, we still have a wide range of preference. A lot depends on the genre that’s being played. When I look at home theatres, I necessarily have to ask the client what their main purpose is. A ghazal afficionado will not buy a system that a gaming enthusiast finds awesome, etc. Similarly, room acoustics for a DJ area is not the same as that for alive area, though it seems to be a trend to have both in the same space these days.

Coming back to speakers, this DIY guy I know (Sreekanth) makes bookshelves and tower speakers that have fantastic detailing, and we’ve had a great time trying out the differences between the systems he’s designed! (Exclamation, yes!). The difference in the soundstage between version 1 and version 2 of his bookshelf speakers is stunning. Version 2 is not for everyone. I took some time to warm up to it. But version 1 had me spellbound. Similarly, his tower speakers for the HT setup made me feel like I was right in the middle of those skyscrapers that Batman was planning to jump on. Leave aside brands, and DIY speakers. ( I will discuss about the genuine talent pool that the DIY club of speaker makers is in another post – cannot do justice to that here).

I’ve auditioned enough systems and find some bright, some clear, some mellow, etc. Honestly, before even discussing fidelity etc, we ought to all get our ears tested. Speech and Hearing institutes typically will only test for speech frequencies, though a couple of them may offer extended audiometry upto 12kHz. I’ve been lucky to have checked the full range of my hearing in my labs at my university, and realized that my hearing is acutely sensitive around the female high pitch range. Which is why Lata-ji will grate on my ears if the volume is too high, while others in the room are perfectly happy. When I tune spaces for sound, I depend on readings heavily for this range, and am able to trust my hearing for all other octave bands.

So, there’s stuff for everyone out here – pocket radios, low-end computer speakers, custom handmade speakers, audio engines, AV systems that the aforesaid vendor sells, and let’s just skip a whole lot of stuff to reach close to the top end at Goldmund home theater systems at 2 crores for a set. AV guys will obviously market the products they deal with, but they should be aware that what they’re saying is not the absolute truth most of the times. Owners of such spaces should be even more aware of this fact. Marketing cannot be the only reason why systems can be priced so far apart from each other.  So in summary, what sounds awesome to one conditioned mind may sound terrible to another. For this reason, audio “shootouts” never made sense to me.

To summarise, there’s a certain terminology of description of sound that is fairly standard, but wide variations are possible at the subjective testing level. Blind AB tests must be carefully structured to get the best results out of them. Very few absolute opinions exist beyond a point. But that’s fine no?  There’s a reason why we’re all not clones of each other, so why should we expect our hearing mechanism and preferences to be identical?

Festival Acoustics : Quick Tip

This part of the recommendations is always free of cost. With everyone gearing up for the festive season, I’m only too happy to provide the name of a brand of ear plugs that I’ve found better than most others. 

Db Safe. Made of washable rubber, available at most medical stores for under Rs. 100,  works better than all the inefficient, memory foam stuff doing the rounds these days. Sturdy, washable piece.  

Please note, I’m not being paid by DB Safe or anyone to do this. I’m only writing this to make the reader aware that help is available just around the corner – at your nearest medical store, and it’s not an aspirin. 

Happy festivities! 

 

Acoustics for Lounges and Clubs – 1

I’ve recently had a chance to look at a few of these projects not six months into my freelancing, and there’s plenty to be said here. Pubs and lounges have integrated themselves into the lifestyles of Bangaloreans for over 10 years now, and plenty of people spend the best part of their weekends catching up with friends and family at such places. This post is for a broad spectrum of audience – aimed at giving general information to people to go to such places, people who design/sell audio, people who own such spaces, and people who live near such spaces.

This post is the first of two, and looks exclusively at operational aspects of such spaces. The second part will go into the technical aspects of soundproofing, interior soundscaping, and sound system engineering.

Why Soundproofing

This is by far the biggest problem required to be addressed for such places, for more reasons than one. For obvious reasons, these places  almost always in the heart of the commercial pockets in various areas in the city, rarely ever on the outskirts. This is usually good news for everyone, because it makes sure they’re not too close to the residences for the most part. Occasionally, when residences have given way to commercial spaces, and some residences are still hanging around on what is now a commercial hub, soundproofing becomes a more critical issue. Like I just said, for more reasons than one:

• Residents face noise issues. Right , easy to guess that. Only thing, they don’t put up with it these days. There are plenty of groups out there lobbying for noise laws to be stringently implemented, and complaints can lead to spot confiscation of music equipment, and repeat offenders can get their license revoked. This is more serious than it appears – places can get shut down in 3 months of taking off. Full Stop. Anyone who doesn’t believe this can call me on my phone, and I will be happy to put you in touch with people who’re facing this issue.
• False Threats: There is another aspect to this : It takes all kinds to make a world, and so there are people who can really live with the noise, but choose to make complaints and harass and extort money from owners. Again, there are some famous people who are known troublemakers in Bangalore  –  who give the rest of the genuine anti-noise lobbyists/activists a bad name.
• Genuine Threats: Residents really do face noise issues : I know this microbrewery that has a reputation for playing extremely loud music. It’s not just residents who face this  (Eg. A glass vendor I was talking to lives about 9 buildings away, and took 15 mins to vent his frustration on how he is completely sleep deprived on weekends because of the loud noise coming all the way from that microbrewery – he said he doesn’t get sleep till they turn off the bloody thing, and has been talking to the welfare association of that layout to press complaints.) Customers also face the same issue – a close friend of mine advised me never to go there with my toddler – her hearing will end up being permanently damaged. She said she their gang of friends couldn’t bear to sit there for even half an hour. Add to it, the place is a metal and glass jungle, the interior acoustics have not been taken care of, and so the music they play sounds bad anyway. I am obviously going to wait for one positive review from trusted sources before I think of going there.

Now, getting an acoustical consultant in early will help owners to relax and run their place happily for years. I’m doing this project where I was roped in rather at the last minute, with tons of changes not possible because many things had already been done. It’s been quite a challenge to work on it, and I cannot assure them that they will comply with the written word of law .That requires measures they’re not willing to implement. So we’ve taken measurements late night, and we’re going to meet ambient noise levels ( which in that space are higher than those stipulated by the law). So we’re really just blending in. However, all measurements are averages, and it is not possible to design for peak noise levels to be contained in. Not the best of things, but with residences right behind them, not doing anything would be far worse.

Why Interior Acoustics

This is the other aspect which is increasingly being paid importance to. With something like 4 restaurants/lounges/pubs opening in Bangalore every month, there’s plenty of competition, and people rely on designer aesthetics, michelin-rated chefs, and plenty of live music and DJ-ing to attract clientele. Now celebrity chefs are fine, but designer aesthetics sometimes don’t allow for even the minimal essential acoustical treatment. The second part of this post will go into detail on what issues we typically see in such spaces.

Why Sound System Engineering 

Now we’ll all just go by our own ears. Fair enough an argument. However, there are also technical factors that go into the design of speaker systems, and while you don’t need to know them in detail, you should still spend time understanding and experiencing the USP of the systems you demo.  My reason for mentioning sound system engineering is that providing the right kind of speakers based on the needs and the type of space will significantly influence the amount of soundproofing and acoustical treatment you will need to spend on. 

Accurate sound system engineering and critical acoustical treatment can make any kind of place sound warm and intimate. Owners of these spaces should take the effort to do plenty of research, because most vendors will usually only try to make the biggest sale they can – that’s their job.  The mid and high end ranges have lots of options, and ideally the sound system should be finalized after the venue has been decided, not the other way round. It seems to be a trend these days to have a DJ space and live area in the same club. The acoustics required are different, but we try to strike a balance between the clear, tight bass needed for smooth music, and the boomy, thumping bass required for EDM.

The next post will discuss the acoustical requirements of such a space.