Simply put - a digital hygrometer is
an accurate means of measuring relative air humidity.
Relative Air Humidity
is the amount of water vapour being carried by the air. As human
beings we are easily able to sense temperature variations- but
are not that well equipped to assess our surrounding humidity levels.
If we are exposed to excessively dry atmospheres for periods of
time - the consequences can be severe. They include sore throats,
coughing, dry skin, tiredness, itchy scalp, increased susceptibility
to colds, damage to hair and increases in levels of dust and static
Yes indeed it does. Temperature is critical because
it determines how much moisture the air can carry. There is a limit
to how much moisture the air can hold. The colder the air - the
less moisture it can carry. If you compare the amount of moisture
in the air with the maximum it can hold at that temperature - then
you get the relative humidity. For example - when the air
is saturated and cannot hold anymore - we say this is 100%
relative humidity. If you warm that air - you increase its
ability to hold water and its relative humidity will drop because
it has the same amount of water in it but it can now hold more.
If there is a big increase in temperature then the humidity will
plummet. Conversely - should the temperature drop then the humidity
will increase - until you reach a maximum humidity of 100%.
At this point water condenses on cold objects - or falls
instruments are particularly affected by humidity - because
wood is "hygroscopic". This means that it naturally takes
on and loses water to maintain a balance with the surrounding air.
This causes it to expand and contract - rather like a sponge - and
explains why close fitting wooden doors sometimes jam shut or can't
be closed in certain weather. During winter months - the
outside air has very little moisture. As this air works its way
into buildings, through draughts from doors and windows - or
by deliberate circulation - it warms up. If water is not added
to this influx of air as it warms - it will become very dry
and the humidity will drop. This is when string instruments suffer.
No - it's not a simple matter.
The microscopic, cellular structure of a tree means that the physical
properties of its wood are not the same in all directions. Changes
in stiffness, hardness and elasticity vary with the orientation
of the grain as does the swelling or shrinkage. Weather-related
changes in the size of a piece of wood are practically negligible
along the grain but can be quite significant across the grain.
Different pieces of wood expand and contract at different rates,
depending on the species of tree the wood was cut from and the
precise orientation of the grain in the sample. The shrinkage or
swelling of the individual components of an instrument wouldn't
be a major issue if they all changed at the same rate and moved
with one another. Grain directions and materials vary and it is
the disparity between the rates of change that can causes the problem.
Even relatively minute dimensional changes can bring disorder.
show that the effect of humidity is greater on large pieces of
wood. This is why cellos and especially double basses - are
more prone to weather-related problems than violins and violas.
Museums keep all their
artefacts in a controlled environment with the humidity level set
at 50% - so for your double bass we would recommend that you endeavour
to keep it in a location with a humidity of between 50 - 55%. In
practice this can be quite difficult to achieve as many modern
buildings and concert halls are made from highly absorbent materials
(e.g. dry-lined plasterboard) and are fitted with air conditioning
- which significantly reduces the ambient moisture content.
In a humidity
of less than 45% - it can take as little as seven days before drying-out
starts to compromise the structure of your instrument. The first
signs may be some relatively minor opening of the seams. With more
time the wood starts to contract and existing cracks start to re-open
slightly. As the table starts to shrink it presses down harder
onto the soundpost and your instrument starts to feel a little "tight".
Instead of concentrating on playing music - the noticeable loss
of sound and tonal quality starts to play more and more heavily
on your mind. You sort of know that something is wrong but you
just can't understand quite why.
You start to notice that
the soft, intermittent buzz, which you had dismissed as just being
one of those things - has quickly developed into something incredibly
annoying for both you and your desk partner. Internal studs may
start to split or even be torn completely loose. You notice fresh
table cracks running up from the bottom edge and now that the alarm
bells have at last started to ring you check over the whole instrument
and notice for the first time that the back centre-seam has come
apart! A hot flush comes all over you - because you know what this
means - it's a back off job and an incredibly expensive repair
bill to fix. You take satisfaction from the fact that you have
the instrument insured but when you get the documents out of the
cupboard to read - you find hidden away in the small print - that
insurance companies will not pay out for damage caused by adverse
atmospheric conditions. Grrr...
As stated in our opening
paragraph - a Digital Hygrometer
is an accurate means of measuring relative air humidity. Here at
The Contrabass Shoppe we use them in each room in which instruments
are stored and think of them as "radars for double basses".
They provide an effective early warning system to detect against
low relative humidity. By purchasing and making use of a Digital
Hygrometer the information that you will receive from its monitor
will be invaluable in helping you maintain the structural integrity
of your instrument. In short - you will gain "peace
Yes indeed. The Contrabass Shoppe's director - Tony
Houska - comments; "All
instruments have value and many of are now worth considerable amounts
of money. You certainly need to protect that investment as best
you can. If there is a simple way of avoiding the cost and inconvenience
of taking your instrument down to your repairer - then it
must be worth taking." He continues - "When you
consider that at least 20-25% of all bass restoration work is due
to damage caused by low relative humidity levels - I would go as
far as to say that a good Digital Hygrometer is an absolutely essential
piece of kit for every bass payer".
Obviously you should try to avoid leaving your instrument
in a centrally heated or air conditioned room. If you find the
level of humidity in the room is slightly below the 50% mark -
then a washing-up bowl or bucket filled half full with water will
help raise the level slightly. In addition
you could purchase and use a Bass Humidifier. You
should regard these two measures as your "first
line of defence". The problem with both of them is that it
is quite difficult to get the water in them to evaporate. Should
your Digital Hygrometer constantly indicate sub-50% readings -
then we would strongly recommend that you invest in a small cool-mist
humidifier - which you should be able to purchase quite cheaply
from most large department stores.
The Contrabass Shoppe Ltd - currently has one make
of hygrometer available... the Hygro-Thermometer-Clock.
The clear - easy to read "jumbo" display of this digital
Hygro-Thermometer-Clock is absolutely perfect for keeping you accurately
informed about the humidity and temperature levels in your bass
store-room. The device features a maximum and minimum reading memory
that can be reset at any time, it has an ice alert and it is simultaneously
able to measure the temperature outdoors. If all that wasn't
enough the device also trebles up as a 12/24 hour alarm clock with
The top line of the display shows the humidity - expressed
as a percentage. The middle line shows indoor or outdoor temperature
which can be displayed as either degrees Fahrenheit or in degrees
Centigrade. The lower line shows the time in either 12 hour or
24 hour clock format.
Yes - here they are;
1) The relative humidity and temperature measurements
and time are displayed simultaneously for direct comparison.
2) The temperature can be displayed in both °C or °F.
3) It has a maximum and minimum reading memory that can be reset
at any time.
4) It has a daily memory reset function. When in the "On" position
max/min memories are reset automatically at 00:00 hours.
5) Both indoor and outdoor temperature can be displayed. The outdoor
temperature is measured using an external sensor that is simply
plugged into the unit.
6) There is a selectable ice point alert. When "On" an
audible alarm will sound when the outdoor temperature drops below
7) It has a selectable 12/24 hour time format
8) It has an alarm clock with snooze function. When the snooze
button is pressed the alarm will be paused for around 8 minutes
and then sound again.
9) The instrument has an integral fold-out table stand or it can
be wall mounted.
10) The unit only requires only one AAA battery.
11) The unit is supplied complete with instruction/operational
card, external sensor with fixing bracket and AAA battery.
As a bass player - every time you put your
instrument down or place it in the store room after the show - those four words "is
my instrument safe" automatically shoot through your brain.
That's just the way it is - and always will be. We all know
far too well that these large instruments are more vulnerable to
structural damage from knocks, scrapes and low levels of relative
humidity than any other instrument in the orchestra. In many instances
those four words just keep going round and round our brain until
we are happy that our instrument is safely stored. For some of
us - we keep mulling over our decision even on the way home. Will
my instrument still be in one piece when I get back tomorrow? Will
my instrument still be in one piece when I get back tomorrow? Will
my instrument still be in one piece when I get back tomorrow?
Common sense usually prevails when it comes
to deciding whether or not to leave ones instrument in a certain
place. We consider the "risks" such as - can it get stolen or is there a
possibility that the percussionist will bash into it when he moves
his timpani into the store. Seldom do we bass player bother to
enquire if the room is climatically controlled or if the air conditioning
has been turned off - as it should. Statistically however there
is a much greater chance of structural damage to our "pride
and joy" from low humidity levels rather than fire, theft
or accidental damage - so why do we seem prepared to take
such a risk? Well it's simply because - we humans - are unable
to sense or feel the amount of water vapour in the air with any
This is exactly why the Hygro-Thermometer Clock
is the perfect piece of kit for home, orchestral store room or
hotel room. Not only does the device provide a clear accurate
reading for humidity - but it simultaneously provides a reading
for temperature and time - with alarm function for those of you on tour - all
in the one compact unit.
You should consider the compact and stylish Hygro-Thermometer
Clock as part of your "insurance-policy" for helping
you maintain the structural integrity of your instrument. This
really is the one accessory that no bass player should be without.
Indoor temperature measurement range: 0 to
+50°C (+32 to 122°F).
Outdoor temperature measurement range: -50 to +70°C (-58 to
Hygrometer measuring range: 20-99%.
Accuracy of hygrometer: +/- 3%.
Accuracy of thermometer: +/- 1°C (+/- 2°F).
Accuracy of clock: 3 seconds per day.
Display resolution: 1%, 0.10, 1 minute.
Display size: 79(w) x 66 (h) mm.
Sampling rate: 10 seconds.
Alarm duration: 12 minutes.
Battery: 1.5V AAA.
Sensor cord length: 3 metres (10 feet).
Product size: 110(h) x 98(w) x 21(d) mm.
Weight inc fitted battery: 146gm.