Atmosphere, Temperature and Humidity
Great care is taken in choosing the woods for an instrument, for this is where the character of an instrument’s sound begins, as well as its beauty and longevity. Wood is hygroscopic. This means that wood has a natural affinity for moisture and attempts to match the moisture content of the air surrounding it. When humidity increases, wood will absorb moisture from the air, and when humidity decreases wood will release some of its moisture content back into the air. Wooden artifacts over 3000 years old found in Egypt continue to show hygroscopic reactions and can absorb and expel moisture from the surrounding atmosphere. These constantly changing conditions can have dramatic effects on a musical instrument and its ability to remain stable and playable. Since the amount of moisture that occupies the cells of wood fiber continually changes, the wood of an instrument can expand and contract thus changing its shape, symmetry and tuning, performance. When instrument wood moves (expands or contracts), even slightly, a change in string tension results, and the instrument goes out of tune. The nature of wood is such that when humidity rises, wood absorbs moisture and swells. When wood is moist for long periods of time, there is danger of mold formation and decomposition of wood fibers. When air is dry, wood releases moisture and contracts. In dry air, damaging wood tensions result from the shrinkage.
NOTE: The air in our (Utah) climate is very dry. Cold winters and furnaces further compound this. Dry air tends to cause contraction, rising of the fingerboard and lowering of the bridge, thus affecting the play and tune performance.
Certain maintenance procedures will help insure the development of wood stability in a new instrument that can minimize wood shift, warping and other damaging wood failures. Consult a qualified instrument craftsman to help insure your instrument develops and maintains correct wood stability.
An instrument feels best in conditions similar to the ones you like. Neither too hot, nor too cold. Neither too moist. nor too dry. It is impossible to continually arrange perfect conditions for an instrument. Adequate measures may be taken to avoid extremes and have been shown to be beneficial in maintaining instrument stability. Ideal storage conditions call for 72° F temperature and around 50% relative humidity.
Keep instruments in their case when not in use. Attempt to store in average temperatures, never too extreme. Excessive heat from a closed closet, car trunk, near a sunny window, or heat ventilator can cause severe wood damage, warping, and glue joint failures. Excessive cold from winter exposure, air conditioning vents etc. can also cause these damages.
3. Use an instrument humidifier in winter months when furnaces are running and air is very dry. Always wipe off excess water before putting into instrument.
4. A room humidifier in homes, or in classrooms also helps where large numbers of
instruments are used and stored.
5. Sudden temperature changes can cause temporary intonation problems. Only in rare cases
will there be adverse effects to the wood. It is best to allow an instrument to change to the room temperature before tuning and playing, e.g. taking a cold instrument into a warm
6. Instruments must be tuned regularly in order to maintain adequate string tension and
maintain the instrument’s stability and equilibrium. Even when an instrument is not being
used or played, it should be tuned and string tension maintained. When an instrument is
not used for awhile, the strings will lose tension and the instrument’s equilibrium will be
changed. Over time, this can result in the sound post and/or bridge falling over, the
instrument warping, or damage due to wood shifting.