Yesterday I compressed my ‘cello
– that is, I turned the tuning pegs, winding up the slack in the strings and gradually started to increase their tension. At first the strings wouldn’t make any noise; and then gradually, as the tension increased, they became audible. At the same time, the wood in the main body of the ‘cello started to creak and groan, and I have to confess I became a little scared.
I started playing the ‘cello when I was five and gave up at sixteen, finding the guitar a much more exciting prospect. During those eleven years of playing, I had given little thought to the forces that the instrument must withstand. Since then I have completed an engineering degree, and so now when I look at the fragile wooden structure I find it surprising that it should be able to resist the forces that the strings place on it.
I remember being told that as instruments in the violin family age they improve because the effect of the tensioned strings is to compress the structure. The strings are stretched from the tuning pegs, over the bridge and loop over the bottom edge and around the sound peg, effectively squeezing the whole box together. This is in contract to a classical guitar, in which the strings stretch from the tuning pegs but stop at the bridge. When guitar strings are tightened, rather than squeezing the box together, the effect is to pull up on the bridge, effectively pulling the front off the sound box. Guitars are therefore said to decrease in quality with age.
I learned the hard way about the physics of guitars at age fifteen when I decided to replace the nylon strings on my mother’s acoustic guitar with steel strings to create a brighter, more jangley sound. Unfortunately the only sound I got was a cracking noise just before I ripped the bridge off of the front of the instrument.
So with that experience in mind, and some engineering under my belt, I was getting increasingly nervous as I upped the tension on my dusted-off ‘cello. The other reason why I was nervous was that until recently this ‘cello had been a collapsed bag of bits in the corner of a basement. The instrument has belonged to my Aunt. Many years ago it got consigned to the cellar, forgotten about, squashed and ultimately broken. About five years ago, it was dug out and my Dad kindly had it restored for me. My end of the bargain was that I would do a little practice now and then. The instrument was reassembled by the late Geoff Crease, the instrument mender that had supplied my first 1/8th-size ‘cello from when I was five. His parting words to me were that though fixed it remained very fragile. That was five years ago. Almost immediately the fingerboard fell off and I lost it, only it to find it again six months ago hiding in the back of the ‘cello case. It has since been stuck back on, and so it was yesterday following a trip with my Dad that I decided to give it ago.
With all that in mind that I found it excruciating to tune the strings up those final few semitones: the strings driving the back of the finger board down on to the instruments shoulders, which in turn put the thin front and back into compression. With every turn of the screw I expected to hear that cracking noise, followed by the implosion of my fragile instrument. And so it was with great relief that the A string reached 440Hz, and I could begin playing – well, scraping.
Since then I have managed two half-our practice sessions. My aim is to get good enough this summer to audition in September for the Angel Orchestra, which M plays in. Whilst tuning up for me was excruciating, I am sure it will be even more so for my neighbours who will have to hear me preparing for that audition. Does anyone have a practice mute?