Air-conditioning for Studios in Asia

Air-conditioning for Studios in Asia
Having experienced the heat and humidity in Singapore for the first time this
summer, I realized that there were practical problems to be faced in the region
which would not be encountered in Europe. It is not just a question of the heat -
there is also the excessive humidity to deal with! Most of the public buildings I
visited in Singapore had air-conditioning units to help cope with this, but I did
notice that the quality of these was variable, as were the associated noise levels. I
visited a number of professional recording studios in Singapore and was surprised
to find that the quality and noise levels of the air-conditioning in these was very
variable also.

So just what is air-conditioning anyway? One definition is that this is the process of
controlling the filtration, air movement, temperature and humidity of the air in a
room or building. Often, these units can be quite noisy in operation and, of course,
noise is the enemy in the recording studio! In order to achieve sufficiently-low
noise levels in studios and control rooms, air has to be introduced at very low
velocities compared with more conventional air-conditioning systems - typically at
1.3 m/s to 2 m/s. Also, it is generally not possible to locate the air-conditioning
units directly within the studio or control room (unless you accept that you will
have to turn the unit on and off as necessary) so a remotely-situated unit
connected to the room via metal ductwork containing suitable noise attenuators
will typically have to be used. All these requirements point to the need for
specialist design. Obviously, there is no shortage of suppliers in Singapore, but for
studios the question is whether to use the normal air-conditioning suppliers or
whether to call in the specialist designers and installers.

On a visit to Yellow Box Studios in July, I had been extremely impressed with the
silent and efficient air-conditioning - the best I had encountered in all of Singapore!
[Yellow Box Studios are a busy post-production facility doing music and sound
design for TV located at 116A Telok Ayer Street - Tel: 0065 222 1278.] I spoke with
Studio Manager Rennie Gomes, who has worked previously at Video Head
Quarters and Schtüng, and he explained: “One unique feature of this studio is that,
unlike the other audio-for-video production houses in Singapore, I’ve got air-
conditioning running throughout the whole studio - and it does not make any
noise! It was designed by Frank Lee and Shah Tahir at a company called Sonic
Valley based here in Singapore. This gives me an advantage over my competitors
and is crucially important when it comes to making the voiceover talent, the
engineers and the clients all feel totally comfortable while they are here for the
very long hours involved in post-production work.” I asked about the haze from
the fires in Indonesia and wondered if this was affecting the studio in any way.
Gomes told me “The haze in Singapore is really not too bad - you can just detect a
slight burnt-carbon smell in the air outside. Fortunately, the air-conditioning
completely removes any trace of this from the air in our studio!” Gomes also
mentioned the latest development at Yellow Box: “We are about to launch the first
Dolby Pro Logic surround studio for TV sound in Singapore - using the Dolby
encoder/decoder with a pair of Yamaha 02R mixers, a Pro Tools system and
Quested monitors.”

This mention of Quested monitors prompted me to call Roger Quested - who I
worked alongside for a time when he was engineering at London's Dick James
Music Studios in the early 1980's and I was producing song demos for this music
publisher - who was well-known for publishing Elton John's songs. As many will
be aware, Roger Quested is highly-regarded in Singapore for his high-quality
studio monitors and is also married to a Singaporean - a fact which not everyone
will be aware of. As he pointed out "It is very handy to have relatives in Singapore
and the surrounding regions who I can stay with when I visit studios and suppliers
in South-East Asia." An anecdote about his first visit to Singapore helps to illustrate
the particular problems of the region when it comes to equipment design. "The
first time I went out to Singapore, about 12 years ago, was part of a 'round the
world' trip I was making to look for local distributers for my speakers. In
Singapore, I had an appointment to see Studer. When I arrived they had brochures
and all the information about my speakers laid out on the table. Now normally, in
that part of the world, they don't ask you whether your speakers are good or bad
- they just ask how much they cost. But in this case the first question they asked
was "What is the surround between the chassis and the cone made of?" I said
"Rubber" and they said "Are you sure, because if that is true, then that is very
good!" I though this was all a bit strange at the time, but the explanation was not
too far away. They took me out to visit a couple of studios including the largest
studio that existed at that time. This studio had JBL speakers which used foam
surrounds that had bits missing. They were rotted away by the local atmospheric
conditions and had fungus on them - and Studer were mostly concerned that this
would not happen with my speakers! At the end of the day they said "if your
speakers use rubber surrounds, that's just fantastic - and we will be happy to take
your line of speakers on for distribution in the region!" Quested also pointed out
the need to constantly check that the air-conditioning is functioning correctly.
"Because everything in South East Asia is so dependent on air-conditioning, if this
goes wrong you get problems. On more than one occasion the air-conditioning in
a studio's machine room has broken down and this has not been noticed straight
away - so all the equipment has gone into thermal overload!"

Talk of machine rooms brought to mind the whole question of studio design, so I
put in a call to David Hawkins at Eastlake Audio. I had the pleasure of meeting
David in 1986 when we were both involved in building the London R & D Studio
for Yamaha. I knew that David had designed the original studio complex for Form
Recording in Singapore some years ago and that Eastlake Audio has a great
reputation for studio design and construction worldwide - actually in 42 countries,
from Iceland to Africa. Currently, Eastlake projects are under way in Abu Dhabi in
the UAE, Chile in South America, Madrid in Spain, and Lagos in Nigeria and it is
probably the case that Eastlake has a wider experience of studio design
geographically than anybody else in the field. "We did a swathe of studios about
ten years ago in Singapore. The people we went to for air-conditioning design
were putting air-conditioning systems into operating theatres at the time.
Operating theatres need very high-quality systems with low noise - as do studios -
so I was confident that they would deliver the results I was looking for." I asked
Hawkins to spell out the main requirements for studios - and a discussion of the
whole subject ensued, prompted by my increasingly-awakened curiosity. "The
three essentials for an air-conditioning system in a professional audio environment

are, firstly, the ability to control temperatures within a required band; secondly,
the ability to refresh the oxygen level of the air whilst cooling the air in a relatively
cost-effective way; and, thirdly, not to introduce unacceptable noise levels into the
environment." I asked David to talk further about noise levels. "There are
internationally recognized Noise Rating (NR) and Noise Criteria (NC) curves by
which noise from air-conditioning is measured. In the US they prefer Noise
Criteria while the Europeans prefer Noise Ratings. You can measure the
performance of any air-conditioning system quite simply by making
measurements with a calibrated SPL meter and entering these onto the relevant
type of graph paper marked up with the relevant curves. The important thing is
that you specify the appropriate NR or NC band and you don't let this be
exceeded. Whether that band will be NR15 or NR20 or NR25, for example, will
depend on the ultimate use of the studio, so, for instance, NR15 would be required
for sound effects recording or for very high quality classical music recording. A
film dubbing studio where very quiet sound effects are recorded will obviously
require more stringently-designed mechanical services and noise controls than one
which is used to originate live TV broadcasts - where NR25 would be acceptable.
Generally-speaking, to keep noise levels low, the size of the ventilation ducts has
to be large enough to permit low velocities of delivered and extracted air." But
what about humidity levels? Hawkins explained: "With temperature control to
typical studio working levels - and in Singapore I would estimate that the studios
run at about 21 or 22 degrees - tolerable humidity levels will automatically be
delivered with conditioned air at that temperature." And how do you get a balance
between recylced air which builds up carbon dioxide content and fresh air with
new oxygen - I was curious to know! "We want to deliver not only enough
conditioned air but also to replenish the oxygen. So we have to look at a minimum
number of changes of the air every hour - and a certain percentage of the new air
supplies must be completely fresh air. You take the same air, cycle it round, but
introduce some percentage of new air on every cycle." Another question which
interested me was whether specialised custom-built equipment is required - as
opposed to off-the-shelf components. On this subject, Hawkins was adamant: "A
totally satisfactory studio system can be built up anywhere in the world from
standard locally-available air-conditioning equipment. It is the way that the system
is designed that makes it appropriate for a studio or not. Size of grills, velocity of
air, ducts behind these, speed of air in these ducts - all these are variables which
have to be juggled." By this time I was beginning to get a feel for the potential
complexities, and I asked Hawkins to explain in some more detail. "Well, for
instance, structural considerations may make it necessary to reduce the duct size
to a degree that the air velocity within the duct is greatly accelerated. In these
cases, the reduced size duct must be followed by a 'plenum box', that is, a large
box with the small duct entering it and a large duct exiting. In this way, the original
duct velocity can be recovered without noise contamination. I like to explain that
this situation is analogous to using an electrical transformer. Imagine you have a
high alternating current travelling along a wide-diameter cable and you need to
pass this through a hole which is not large enough to take the large diameter cable.
In this case you could use a transformer to step up to a high voltage low current
which would go through the hole on a thin wire, then transform this back on the
other side and continue using a thick wire." It is often helpful to consider analogies
with other systems, and, as a former electrical engineer, I particularly appreciated
this explanation. To finish off the discussion with Hawkins I asked him to comment

about the use of silencers within the ducting. "Often acoustically-separated areas
within a studio are served by the same air-conditioning machinery. Where a high
level of building acoustical isolation exists between two adjacent areas, it may be
necessary to fit inline duct attenuators to prevent crosstalk between the isolated
areas via the ductwork. Similar to car exhaust silencers, these present an acoustic
labyrinth which muffles the sound on its way through."

At this point Hawkins had to get back to his consultancy work, but I was just
getting 'warmed up' on the subject - so I called another UK-based expert who has
extensive experience overseas. This time I spoke to Mike Hardy who runs
Ambthair Services, based in Horsham in Sussex [Tel: +44 (0)1403 250306, Web:
www.pncl.co.uk/~mhardy] who introduced himself briefly before continuing the
discussion. "We act as consultants and work on designs for Asia and we also do
installations in Europe. We often work for Studio designers such as David Hawkins
and Andy Munro, and we recently worked on a project for Famous Ciné Films in
Bombay with Munro Associates. The feedback from that project is that we have
given them the quietest air-conditioning system in India. We have also been
working as consultants on the MegaForce recording studio project in Taiwan with
Andy Munro." I asked Hardy to outline some of the issues he considers to be
important. "Well, for one thing, normal air-conditioning installers either
overspecify or underspecify the system - which can lead to major problems - so
studios should always employ a specialist designer. Moisture removal is an issue. If
the equipment specified is marginal it won't take enough out. If it is over-specified,
you can get too much humidity left in the air. It is important to get the balance just
right between cooling and humidity. Another thing to bear in mind is that, often,
as equipment is added to studios, they can outgrow the air-conditioning! Also, if
machine room temperatures are too high, equipment housed there will become
unreliable. So the air-conditioning requirement needs to be looked at every so
often to see what changes or upgrading may be needed. Some equipment is more
reliable than others and reliability varies hugely from manufacturer to
manufacturer, so you cannot just buy anything. The good news is that three year
equipment guarantees are now commonly available rather than the former
twelve-month guarantees!" So how does Hardy go about developing a
specification for a client? "Well, the first thing to ask the client is how quiet he
wants it to be, and then you need to ask how much heat is given off by his
equipment. Once I know these two basic facts I can start to discuss the various
options and their costings. So, for instance, a cheap split unit design to go to NR25
could cost as little as £2-3000 while a ducted system for the same room would cost
more like £5-6000. If you are talking about a suite of rooms, depending on
circumstances, costs could be as low as £4-4500 per room. To achieve NR20 or
NR15 you will definitely need to use a ducted system - otherwise the best you
could achieve would be NR25. Bear in mind that a ducted unit needs to be located
above a false ceiling or outside the room or building and you need to use silencers
to keep it very quiet - so costs can escalate depending on the circumstances." And
what about standard versus special custom equipment? "With capital costs as
important as ever these days, the trick always is to use standard equipment which
is produced for the massive world-wide air-conditioning market. Like cars, mass
production drives costs down while specials push costs up. In most cases it is
possible to avoid using specials and, for most studios, manufacturers may be
found with suitable mass produced equipment within their range."

So there you have it - a brief look at air-conditioning for professional recording
studios. It is clear that studios in Singapore should be looking to specialist
designers to ensure that their systems are up-to-date and working correctly - and
new installations should bring in the specialists at the outset. Costs, especially for
smaller post-production studios and musician's projects studios can be kept quite
reasonable, especially when standard components are used.

Mike Collins © 1997