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A R T I C L E S
Set-up - an introduction
Guide to cello measurements
What is a full-sized cello?
Bridge design
Taming wolf notes
Humidity and cellos
Understanding cello varnish
Tailpieces and tailcords
The challenge of trying cellos
Left hand comfort for cellists
Right hand comfort for cellists
Healthy cello backs
Cello benefits
Cello
transport
Cello cases - survey report
Funding for cellists
Review of A and D strings
Review of G and C strings
New cello strings 2009
Survey
of string design
G.B. Guadagnini's cellos
Study of 1729 Guarneri cello
Bow sound
Bow testing techniques
The
appeal of bows
Players test bows
Saving the Pernambuco
C E L L O S
Cellos for sale
Bows for sale
Cellos by Robin Aitchison
Video Gallery
Cello set-up
C E L L O E X C H A N G E
Cello exchange
S T R I N G T R I A L S
String Trials
A B O U T U S
Cello specialists
Biographies
Feedback from cellists
Travelling to Ely
Contact us
C E L L O C A R E G U I D E
Cello Care Guide
Order free copies
A R T I C L E S & N E W S
Articles and Newsletters
L I N K S
Links
C E L L O S
Cellos for sale
Bows for sale
Cellos by Robin Aitchison
Video Gallery
Cello set-up
C E L L O E X C H A N G E
Cello exchange
S T R I N G T R I A L S
String Trials
A B O U T U S
Cello specialists
Biographies
Feedback from cellists
Travelling to Ely
Contact us
C E L L O C A R E G U I D E
Cello Care Guide
Order free copies
A R T I C L E S & N E W S
Articles and Newsletters
L I N K S
Links
C E L L O S
Cellos for sale
Bows for sale
Cellos by Robin Aitchison
Video Gallery
Cello set-up
C E L L O E X C H A N G E
Cello exchange
S T R I N G T R I A L S
String Trials
A B O U T U S
Cello specialists
Biographies
Feedback from cellists
Travelling to Ely
Contact us
C E L L O C A R E G U I D E
Cello Care Guide
Order free copies
A R T I C L E S & N E W S
Articles and Newsletters
L I N K S
Links
C E L L O S
Cellos for sale
Bows for sale
Cellos by Robin Aitchison
Video Gallery
Cello set-up
C E L L O E X C H A N G E
Cello exchange
S T R I N G T R I A L S
String Trials
A B O U T U S
Cello specialists
Biographies
Feedback from cellists
Travelling to Ely
Contact us
C E L L O C A R E G U I D E
Cello Care Guide
Order free copies
A R T I C L E S & N E W S
Articles and Newsletters
L I N K S
Links
C E L L O S
Cellos for sale
Bows for sale
Cellos by Robin Aitchison
Video Gallery
Cello set-up
C E L L O E X C H A N G E
Cello exchange
S T R I N G T R I A L S
String Trials
A B O U T U S
Cello specialists
Biographies
Feedback from cellists
Travelling to Ely
Contact us
C E L L O C A R E G U I D E
Cello Care Guide
Order free copies
A R T I C L E S & N E W S
Articles and Newsletters
L I N K S
Links
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Humidity and Cellos
We explore the foggy world of
humidity, explaining how humidity affects cellos and how it can be
controlled safely.
2010 was the most severe winter in Europe for thirty years and this
spring we received a host of phone calls from cellists who were worried
that their cellos had lost their tonal beauty and ease of response. We
also spent a lot of time re-gluing seams which had opened during the
harsh winter. Most of us are aware of SAD (seasonal affective disorder)
and the havoc it can play on our moods but cellos also suffer from
seasonal changes. They don't mind the dark winter days but they hate the
dry air in our centrally-heated homes when the temperature outside drops
near or below freezing.
The level of moisture or humidity in the
air affects the
tone and condition
of cellos because
wood is porous and
will - like a very
stiff sponge - automatically adapt
to the humidity in
the air around it. When the level of humidity in the
air rises, wood
expands as it
takes in some
of the increased moisture; when
the humidity
drops, moisture is leached from wood by a process of diffusion, causing
it to shrink.
What is Relative Humidity?Relative humidity (expressed as a
percentage) indicates the amount of water vapour held in the air at a
specific temperature, compared to the maximum amount of water vapour
that the air could hold at that temperature before
Michael Edwards
condensing into dew,
fog, rain or snow. 40% relative humidity means that the air is holding
40% of what it is capable of holding before reaching the dew point, when
the moisture in the air will start to condense.
Fortunately, cellos are designed to adapt to modest changes in humidity
because the arched shape of the front and back will rise and fall as the
wood expands and contracts. However, even modest changes in relative
humidity can have a noticeable effect on the sound of the cello and
extreme changes can cause damage. The best humidity for your cello
depends on the prevailing humidity level when the cello was last glued
together and/or set up. Cellos are generally most comfortable between
40% and 60% relative humidity. 30% is too low for comfort and 20% is
hazardous.
In dry conditions (below 40% relative humidity) the arching of the front
and back will shrink down onto both ends of the sound post, which can
make the response of the cello dry, harsh and excessively resistant. If
the wood contracts further, stresses from the changes of shape will tend
to build up near the top and bottom of the instrument because the
arching is fairly flat in these areas and therefore cannot change shape.
If these stresses increase gradually, the animal glue attaching the
front and back to the ribs will release at the points of tension. The
tone of the cello will suffer due to the newly-opened seams, but no
damage will have been done to the plates. However, if a sudden and
extreme reduction in humidity occurs and the seams do not come unglued,
cracks may form in the front or back. Another common symptom of low
humidity is a reduction in string heights; differential rates of
shrinkage in the neck root cause the neck angle to change, encouraging
the bottom of the fingerboard to rise up closer to the strings. (see
table below showing common symptoms of
low and high humidity in cellos)
In conditions of high humidity (over 60% relative humidity) the cello
may lose resistance and projection as the plates slacken and the sound
post becomes too loose. The neck root will expand on the varnished side,
thus making string clearances higher than usual.
Air temperature has a big impact on relative humidity. For example, if
the relative humidity of the air outside in winter is 40% and the
outside temperature is 8°C, as soon as the air moves into a heated house
and is warmed to 20°C, the relative humidity of the air will drop to a
dangerously low 18%. For this reason, the most hazardous time of year
for cellos is during the winter months when central heating drives down
the relative humidity of air which is already lessened by the cold
conditions outside. Relative humidity in the USA plummets as low as
10-15% in heated homes and even in the UK, a centrally heated home on a
freezing January day set to 20°C could drive the indoor environment down
to a dangerously low relative humidity.
The best way to monitor humidity levels is to use a battery powered
digital hygrometer in the room or case where you keep your cello.
Hygrometers are not expensive and they are small and portable. If the
humidity in your room is too low you can use a room humidifier but a far
cheaper, simpler solution is to keep your cello in its case whenever you
are not playing it and to use a case humidifier to keep the humidity at
a suitable level. It is also sensible to use a digital hygrometer in
your case so that you can check the environment around your cello and be
reminded when you need to moisten your case humidifier. Built-in
circular (non-battery powered) case hygrometers are notoriously
inaccurate but some modern digital case hygrometers are very reliable.
Hygrometer test. We tested three digital hygrometers for this article:
Planet Waves, Oasis and Stretto. Planet Waves consistently registered a
lower humidity reading than either Oasis or Stretto and was also less
sensitive to humidity changes. Since Stretto agreed most consistently
with our control hygrometer, we chose Stretto as our favoured
hygrometer, but Oasis was also very reliable and a little less bulky
than Stretto. Further information about these models is listed
below:
Humidifier test. We then tested three case humidifiers (Planet Waves,
Stretto and Oasis) using Stretto hygrometers in three identical
fibreglass
cello cases, placing a different humidifier in each case. We kept the
cases in a humidity controlled room, left each case open for about one
hour each day, and took daily readings from the three cases for seven
days. We used large-sized Stretto and Planet Waves humidifiers in our
cases; the Oasis humidifier is only available in a small size.
In this first test the Stretto humidifier was consistently the best
performer. The Planet Waves came a credible second but the Oasis did not
make much impact on case humidity at all.
In a second test we used Stretto as our control humidifier and compared
its performance with a ‘Dampit’ style green snake humidifier and a
homemade device made from a 35mm plastic film canister with holes
drilled in the ends and a piece of dampened sponge inside. In this test
the ‘Dampit’ style humidifier raised humidity even more than the Stretto
during the first 24 hours but its performance soon dropped away. The
home made canister device was inadequate for a cello case (its
performance was similar to the Oasis).
This second test showed that the traditional ‘Dampit’ style humidifier
has a powerful initial effect but it must be re-moistened daily to
maintain its performance and it must also be used very carefully to
avoid damage to the cello and varnish. The Stretto maintained its
performance throughout the test period and we would suggest re-soaking
its crystal bag every week. The Stretto is less likely to damage an
instrument than a ‘Dampit’ style humidifier, as moisture is absorbed by
a bag of hydroscopic crystals and cannot leak onto the instrument. (See
further details below).
Humidifier manufacturers recommend re-charging humidifiers with water
every 1-2 weeks but the safest approach is to check the case hygrometer
every morning when you open your case, and re-charge the humidifier if
necessary. Another factor to consider is the air-tightness of your case;
if the case is not well sealed or if you tend to leave it open for
extended periods, you will need to recharge your humidifier more
regularly. It is most effective to use distilled or de-ionised water in humidifiers so
that the absorbent sponge or crystal does not get clogged up by mineral
deposits as the water evaporates. For more detail about distilled
or de-ionised water, see
below.
Case study. Colin Carr and his Gofriller cello travel between the UK and
the USA many times a year in a busy solo touring schedule. Colin
explains how he keeps his cello happy:
'Over the years it has become clear that the cello does not do well
in extreme dryness or humidity, but I have gradually learned to control
the environment around the cello so that I never have to worry about
changing bridges for summer and winter. I use a room hygrometer as I
find they are more accurate, and try to maintain my cello at 40-50%
relative humidity. Whenever possible I use a room humidifier, but if the
dryness is extreme I will use a Dampit as well. I always put a Dampit in
when flying. In hotels, running the shower for ten minutes is an
effective humidifier (keep the plug in so the humidity lasts longer).
When I can't use a room humidifier I drape a large damp towel over the
whole cello case with the cello inside. It's possible to raise the
humidity in an instrument locker from 25% to 60% using this damp towel
method and as long as the towel isn't dripping wet, there's no danger of
over doing it. In hot concert halls I don’t worry too much about the
cello as I create a lot of humidity when I play!’
© Robin Aitchison and Sarah Mnatzaganian 2010.
Details of some of the hygrometers
and humidifiers reviewed
in this article and how to use them:
Stretto digital hygrometer
• Dimensions: 76mm x 58mm x 15mm
• Dual LCD display showing both temperature and relative humidity
levels
• Temperature displayed in both Fahrenheit and Centigrade
• Records maximum and minimum temperature and humidity
• Internal clock
• Supplied with a detachable, velcro fastening to fix to case interior
• Battery included.
• On/off switch
Stretto Cello Humidifier
• Perforated plastic container 95mm x 65mm x 15mm
• Attaches with Velcro to the inside of the case.
• Supplied with two microfibre humidification bags filled with
hydroscopic crystals
• Fresh bags can be ordered separately
To use the Stretto humidifier, immerse one bag in distilled water for 5
minutes, until it is swollen up in size. Dry carefully and place inside
the perforated container. Stretto advise fitting the humidifier and
hygrometer to opposite sides of the head of the cello case. Re-charge
the bag with distilled water as soon as the humidity in your case starts
to drop below a comfortable level. Bags can be re-charged with water
many times, but need changing when they no longer absorb water. .
All Stretto products - and strings - can be ordered from J & A Beare Ltd; contact
Louise Smith on 020 7307 9650 or email
louisesmith@beares.com.
Other online suppliers are also available.
Planet Waves Humidity & Temperature Sensor
• Black plastic oval 100mm x 70mm x 30mm
• Measures relative humidity levels 20% to 99%
• Temperature displayed in both Fahrenheit and Centigrade
• Programmable set point monitors the minimum humidity desired
• A warning icon indicates when it is necessary to use a humidifier.
• Indicates the highest and lowest temperature and humidity levels
• Battery provided
Planet
Waves Large Instrument Humidifier
• Black plastic perforated oval 120mm x 70mm x 30mm
• Contains open-celled phenolic foam.
The humidifier is charged using 1-2 syringes of distilled water,
inserted into a nozzle point. Despite the presence of hydroscopic foam
inside the humidifier, we managed to shake water out of our Planet Waves
humidifier after charging it with water, so we would advise giving the
humidifier a good hard shake into an absorbant towel, to ensure that no
water can escape.
Both the Planet Waves sensor and humidifier can be fitted with velcro
into the head of the cello case. They can be ordered from:
www.alangregory.co.uk,
www.thestringzone.co.uk
and other online suppliers.
Oasis® Digital
Hygrometer/Thermometer
• Dimensions:
101mm x 32mm x 10mm
• Measures relative humidity and temperature
• Records high/low temperatures
• Measures temperature in Centigrade or Farenheit
• On/off switch
• 5 year guarantee
• Measures 20% to 90% Relative Humidity
We were not able to find a UK supplier
for the Oasis hygrometer , but it can be ordered from the USA from:
http://www.oasishumidifiers.com/hygrometer.html
Dampit and Green Snake
products can be bought from most music shops.
• Green perforated rubbery tube filled with absorbent yellow sponge
• 350mm long, 10mm diameter
• The top end is plugged with a wide-headed bung which sits in the f
hole.
After soaking in distilled water, make sure that you wring the
sponge-filled tube out well to remove excess moisture and shake it
sharply to ensure that no further drops of water escape. Then dry the
outside surfaces very carefully with a towel before inserting into the f
hole. Use this style of humidifier with great care as
over-moistened humidifiers of this design can cause damage to the
varnish around the f hole where the head of the humidifier sits. If
water drips from the end of the product onto the inside onto the bottom
of the cello, it could cause damage to the varnish, distortion of the
rib wood and ungluing of seams at the base of the cello.
Distilled or De-ionised
Water
Humidifiers work much more effectively
and last for much longer if you hydrate them with pure water which does
not contain minerals. Distilled water used to be widely available in
chemists, but it less popular now than de-ionised water which is much
cheaper to produce than distilled water. Both distilled and de-ionised
water are ideal for use in a humidifier. De-ionised water is sold in
car shops, garages and supermarkets, but some de-ionised water products
which are sold for topping up car batteries do contain additives, so do
check that you are buying plain and simple demineralised water!
Accreditations to look out for include ISO 9001:2000 Quality Assurance
accreditation. Apparently B&Q, Halfords, Homebase, Asda and Tesco all
sell simple deionised or distilled water. Some are own-brand, and some
by Tetrosyl. The Distilled Water Company delivers free within the M25
area of London; their address is:
http://www.thedistilledwatercompany.com/purchase-distilled-water/ |
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