You are sitting comfortably in the other room, reading a book, and you hear a god-awful bang…. It sounds like your harp has split in two! Don’t worry – it’s just a broken string. But you’ve never changed a string before! It can seem quite intimidating the first time you have to wrangle with a slippery, uncooperative nylon string, but it’s really quite a simple process that just takes a bit of practice. For anyone who may not have a teacher or harpist friend to show them how to tie that special “harp knot” (it’s really not hard, essentially just a loop within a loop), the folks at Wm. Rees have an excellent set of instructions, including pictures, here. If you know someone with the old standard, Sylvia Wood’s teach-yourself harp method book, she also has a good diagram with instructions in the back of the book. You can practice the knot with a piece of string a few times first; I also recommend practicing on the broken string, since the nylon is stiffer and more likely to slip than a piece of twine.
Strings don’t just need to be changed when they break – it’s also a good idea to change them if they start to sound dull, or have developed obvious weak spots (which might mean they are prone to breaking, and you don’t want that to happen in the middle of a gig). Some people change their strings periodically just as a matter of course, to keep the harp sounding bright; if you’ve had the same set of strings for a number of years, it might be time to consider gradually replacing them with new ones. Some people dive right in and change the whole set all at once, but this isn’t necessary; you can start by changing the ones that sound a little dull, or all the bass strings, or one octave, and do the others over a longer period of time. Or, you can set aside an afternoon and do the whole harp.
Keep in mind that any new string will take a while to settle in (nylon strings stretch); you’ll want to check its tuning several times a day for the first couple of days, and should probably tune it every day for a week after that. If you absolutely have to change a string during a performance, you will need to tune it during every break, and possibly after only a couple of songs. If you’re worried about taking the time to tune the string frequently, you can either try to leave that note out of your playing, or you can explain to the audience what you’re doing. Most people will have no problem with you tuning a bit more often, if it means the harp will sound better. Our medieval ensemble regularly has to re-tune after several pieces; we usually delegate one of our members to be MC and talk to the audience a bit while we’re doing it. If you’re playing solo, you can use the time you’re tuning to talk a bit about the harp, or the pieces you’re playing, or tell a story or amusing anecdote.