As I write this post, the temperature is hovering around freezing here in Washington DC, where I live. A delightful freezing rain and sleet mixture is falling - Washington is famous for its "wintry mix" and today is a classic example. But fear not! I'm toasty warm here in my house. My radiators are working great and the place is nice and warm. Unfortunately, these radiators are also reducing the relative humidity in my home, taking air already dried out by cold temperatures and making it even drier by heating it up. That air in turn dries out the wood that my basses are made of, and that can make weak spots in the wood fibers stretch out and crack...
Everyone who plays a string instrument has to deal with the issue of keeping it adequately humidified. At Peabody, we bassists have some institutional help. In the rooms with bass lockers, we have large room humidifiers which keep the humidity at a safe level (around 40-45%). We also have a good system in place for keeping them filled and working. But when any of us takes our bass out to rehearse or play a concert, he or she moves it through various halls and rooms that don't have humidity control. To try to keep the instrument humidified, we should use a device to keep the interiors of our basses as close to optimal humidity as we can.
Unfortunately, our options are not great. Many bassists use the Dampit or a similar brand of sponge humidifier. In my experience, these have several problems. For one, they need to be very thoroughly squeezed out before you put them into your bass, because otherwise the water in them can drip out the bottom of the Dampit onto your bass interior (not a good thing). This means that you also have to re-wet them quite frequently, which can be a hassle. And most importantly, I feel that the overall impact a single Dampit has on the interior of a bass is pretty negligible. Take a look a the Dampit of a violin, and compare its size to the violin's size. Then imagine how large a bass Dampit would have to be to be the equivalent size - enormous! I just don't think there is enough surface area on a bass Dampit to adequately moisten such a large space as the interior of a bass. Even if you use many Dampits - I've used up to eight at one time - they still probably don't suffice to raise the humidity meaningfully. It is true that I've never actually inserted a hygrometer into a bass using Dampits to check on the humidity, so perhaps I'm mistaken and they work better than I think. But I'm skeptical that they are all that effective.
That said, what other options do we have? Not many. Our basses will probably have to spend time in dry environments, unless we're one of the lucky few living in a climate without any extremes of hot dry weather or wintry cold. I took some advice from my friend and bass colleague Jason Phillips and made my own bass humidifiers from his model. I think that they have more surface area overall and release more water then Dampits, plus they extend further into the bass. Here's the recipe:
Jason Phillips' Bass Humidifiers
2 large kitchen sponges
2 plastic Ziploc-type bags. I used to use a type that was sold as "breathable" and had lots of teeny holes in them to allow air to circulate. These must have not been very commercially successful, since I haven't seen them in stores for awhile. If you can find them, buy them and give some to bassists everywhere... If not, follow the instructions below.
4-6 feet of nylon fishing line, available at any sporting goods store
1 safety pin
Tie the line fairly tightly around each sponge, then moisten the sponges and squeeze them out enough to that they won't drip into your bass. If you don't have the breathable bags, poke lots of holes into your plastic bags with the safety pin. Then slip the bags over the sponges, and insert the sponges into your f-holes. The nylon line should rest on the bridge.
I use two of these on my bass when it's going to be out of its humidified room for awhile, and I think that they produce more water vapor than do a bunch of Dampits. Plus, the sponges are further inside the body of the bass, so more of the humidity stays inside the instrument rather than going out the f-holes. And, once inside the bass, you can barely see them!
All that said, none of these devices are a substitute for keeping your bass in a well-humidified room as much of the time as you can. Most importantly, don't expose your instrument to sudden extremes of temperature and humidity.
None of these solutions are fantastic in themselves. So, do any PBDB readers have some good suggestions on keeping your bass humidified? Post a comment and let the rest of us know!
Sadly, the best news I can offer about humidification is this: The reason the seams of our instruments are sealed with hide glue, rather than a stronger type of glue, is that the seams are designed to pop open when the top is stressed by humidity changes. Without this feature, the wood of the top itself would crack much more frequently. So, when your seams open up in the winter, be happy - it could be your top cracking instead.