Humidity and Temperature, and How They Affect Your Instrument

Humidity and Temperature, and How They Affect Your Instrument

You may be aware of this, then again you may not, but temperature and humidity directly affect the performance and structural integrity of your instrument in a few ways.

Let's deal with the temperature first, assuming humidity is low or at least average for the instruments location. A high temperature will cause the instrument to dry out: the moisture content in the instrument will be reduced. On the surface, this might seem like a positive thing, however, it's not always.

When the wood in your instrument begins to dry out, it begins to move and contract in strange ways. In an extreme, this can cause the wood to crack, split, or become separated from a once stable glue joint. Instruments produce music by sound waves caused by vibrations. If the wood is cracked, the wood on either side of the crack runs the risk of knocking against each other, creating a buzzing, humming, or ringing sound that is distracting and unpleasant to listen to.

There is little chance of your instrument being exposed to extremely low temperatures. But even if it is, chances are it won't affect your instrument at all, but the humidity that often comes with cooler temperatures will.

Humidity is the moisture content in the air. When the humidity goes up, the air tends to feel thick, sticky, and has even been defined as "swampy." A majority of any instrument is made up of wood, which is directly affected by it's moisture content. When the humidity goes up, the moisture content of the wood goes up. When the humidity goes down, the moisture content of the wood goes down.

When the wood in your instrument has a higher than average moisture content, the wood will swell, or become enlarged. Most obviously this causes stress between any joints in the wood, weather it be by glue or a small nail. If the high moisture content is maintained over a period of time, it can cause the wood to swell to the point that the joint breaks, damaging the structural integrity of your instrument and usually affecting the tonal quality by adding the same buzzing, jangling, or ringing sound discussed earlier.

So what is ideal for an instrument? Where can it be perfectly comfortable? It's very simple. Instruments are like people. They like to be cool, but not to cool, and they don't want the air around them to be thick or "swampy" due to high humidity. Most instruments like to sit between 73 and 78 degrees Fahrenheit, and with a 45% to 50% local humidity. A few more or less degrees in temperature or humidity won't really affect your instrument.

This is why you should never leave your instrument in your car. It gets hot, the case it's in causes the temperature in the case to be slightly higher than the interior of the car, and depending on the humidity that day the instrument will begin to swell or shrink, risking breakage of your instrument.

Now, how can all of this affect the instruments performance. Picture this scenario. You're on a concert stage in front of 800 people, with a 60 piece orchestra behind you. It rained yesterday so the humidity is high but you don't need to worry about it because the concert hall is air conditioned. You're the cello soloist for Dvorak's concerto, and are about half way through the 40 minute piece of music.

The air conditioner, which has been in need of service for some time, gives out. Within minutes, all of the bodies, people breathing, etc. cause the temperature and the humidity in the room to rise rapidly. This in turn causes your instrument to swell. The body of your cello is pushing up on the bridge, which in turn is also swelling and pushing up on the strings. Your strings were sitting at a tension of 50.21 pounds, and was perfectly in tune. With the added and somewhat uneven swelling of your instrument pushing up on the strings and adding tension, the total tension in weight is now 52.87 pounds. Your cello is now noticeably out of tune and above standard concert pitch of A440.

The rest of the orchestra suffers the same problem, and now your music sounds discordant, disjointed, and generally...well...very bad. Not to mention your body is dripping with sweat. The director waves every to a stop, and dismisses the orchestra, apologizing to his audience for the uncomfortable room, and promises them another concert the following evening.

Not so fun, is it? Now, this example was slightly exaggerated. However, under an extreme like this it could happen very similarly to what is described.