On Changing Bass Strings
Changing strings on a string bass can be more challenging than anticipated. There's always the possibility that the soundpost or bridge will move or fall down .Certainly the bridge top will pull forward (toward the scroll) when the new strings are installed and there's a lot of winding to do with those long strings. Even for people who have played for years, changing strings can be a little intimidating. A system is very helpful to minimize problems.
First, assuming your setup is as you like it, mark the bridge and soundpost placements to later determine if they moved and to allow you to move their setup back to the original location. Change one string at a time, tuning the new string up to full pitch before going on to the next string. It doesn't matter in which order you change the strings. I usually start with the G string and work my way down. If the D string's location makes it difficult to access the G string: loosen the D string a few turns to push the D string off the G. This maintains pressure on the top to keep the soundpost in place.
I recommend a winder. We make one that attaches to both a hand drill and an electric screwdriver. If you're on the road an electric winder may be too cumbersome to carry. Instead, you can buy a hand powered swivel roller type for about$10. These are small and easy take along on the road. But in case you don't have a winder, I'll describe a way to change the strings without one.
Unwind the first string you're going to change until the part that is wrapped around the string roller starts to unfurl and fall away from the roller.(see photo example 1-tuner anatomy) Allow the end of the string to be freed from the rest of the string that is wrapped around it. Now you should be able to push the string end toward the hole in the roller and pull this end through the hole. Sometimes, especially if the string is installed correctly, your fingers alone will do the job. At the shop, I use forceps that I suggested for the first aid kit in a recent column. Needlenose pliers will also work. If the previous installer tied a knot to really 'secure' the string around the roller, it may require some real patience to unknot it. You'll never secure the end of the string around the roller with a knot again.
When installing the new string, start by positioning the hole in the string roller so that it runs from the nut to the scroll. In this way when you insert the string through the hole it won't be blocked by the back of the pegbox and you'll be able to grab the end to further pull the string through the hole. Pull the string through the hole so that about 1/3 of the fabric wrapped end of the string is sticking through.. Take this loose end and wrap it around the fabric wrapped section that has not passed through the string roller(see photoexample 2) . If you are not using a winder, pull the string through so that there is very little slack left in the section of string that is actually played. That is, about 3/4 of the fabric end should go through the roller. In this way you'll only need to twist the string around the roller a couple of times before it grabs. There will be a long piece of the end of the string sticking out, don't clip this off. Tuck it back under the string rollers and adjust it if it buzzes. If you clip off this long loose end it will become a problem if you later decide to lengthen the section of string behind the bridge by shortening the tailpiece wire or use that string on another bass with a longer string length. The main objective is to make sure that the string overlaps itself on the string roller at least once.
The strings should not cross each other while in the pegbox. This will cause unnecessary friction and wear. Some players like to roll the string neatly along the roller which is great as long as the string is being pulled straight back on the same line as it is intended to be played.(See photo example 2)It's alright to have the string wrap over itself several times as long as the thickening spool clears the back of the pegbox. Be careful to avoid pinching the string between itself and the cheeks of the pegbox. This can occur when the spiraling twist of the string literally pushes itself laterally.(see photo example 3)where it becomes pinched against the side of the pegbox. This problem is most common with the E string because its width accelerates the lateral movement.
Make sure that the string grooves in the nut are wide enough for the strings to pass through without binding on the side of the notch. There are many different string thicknesses so, for example, if you're changing from solo strings to orchestra tuning strings or from metal to gut strings the groove has to be wider. A notch in the nut or bridge that is too wide is fine as long as the string rests on the bottom of the notch and that you're happy with it's location with respect to the other strings and the side of the fingerboard. We recommend lining these grooves with graphite (pencil 'lead') to lessen the friction as the string passes through while tuning.
In general, the E string's life expectancy is lower than the other strings. They tend to lose their volume and focus more quickly than the others. The actual string life depends, of course, on the amount of playing done and how well the string was maintained. If you feel your strings are dead in 6 months then try changing the E string in 3 months and then the entire set in 3 more months. Simple string maintenance consists of wiping the strings down with a clean cotton cloth after each use. If rosin builds up, wipe the strings down with rubbing alcohol on a cloth. Just a little alcohol will do and make sure not to get any on the varnish. Finally, the bridge thickness at the notches should not be less than 3.5 m.m. or the bridge top will tend to separate the string winding.