Jonathan's Carriacou diary: Phonograph

Day 1

I had an idea I knew what the challenge would be for this programme. I thought it might be a communication device to go with the map making. It wasn't: it was to build a device to record sound - a phonograph - that's a tricky one!

The basic idea is simple. Capture the vibrations of sound in some way, store them and then replay them back when you want to hear the sound. Way back in the last century Edison used a rotating wax disc to store the vibrations that sound created at the end of a large metal cone. The cone had a needle attached to it and when this was carefully set in the wax the sound was stored as a series of hills and troughs as the wax moved. Repositioning the cone and needle onto the start of the groove and moving the wax recreates the vibrations which moved the needle and the cone setting up the same sound waves again - recording and playback are therefore possible. Making one work is however very difficult and I remember reading that it took Edison many years (thousands of hours) to perfect.

Built the basic apparatus for the phonograph. Wax loads up well on the cylinder. Screw mechanism and handle work really well with a bit of coconut oil as lubricant. Tease Kate on camera that I have already recorded a donkey!! I turn the handle of the squeaky mechanism (before I put the oil on) and it goes eeeooorrr eeeooorrr!!

Load up the wax onto the cylinder and Kate and I paint on layers of white normal candle wax and yellow beeswax. Used a chisel to cut it down to a cylinder and then a razorblade. The thing looked beautiful like onyx or marble.

Day 2

The Rain in Carriacou falls mainly on the Rough Science Crew

Rained and rained and rained last night - very stormy.

Mike L's birthday today. I had thought about this before we left the UK and so I packed the best present I could think - something that Mike might like to cause a little havoc with - a water pistol! Kathy and Mike L go map making all day. Poor them - it rained and it rained.

Kate and I cut the wax today so that the cylinder was as smooth as could be. There were a few potholes on the surface so we spent some time filling them in and re-filing/cutting. Try out a first test with a nail attached to a tin can. The tin can was to act as a sound-collecting device while the nail used to cut the groove and convert sound into vibrations on the groove. This didn't work really although we might have recorded some kind of sound from one of the loud "hellos" I shouted into the can.

Spend the rest of the day making up a sound box to go on the end of the large metal funnel. This was a little cavity that goes on the funnel and increases the amplitude of the vibrations for a given sound. Tried many different types of diaphragm, but an old tuna can with a wooden fitting to fix the funnel worked the best. You could talk into the cone and easily feel the vibrations on the bottom. Fixed a drawing pin in place as the groove maker. Tomorrow we test the new gear on the wax.

Sat out with Kathy and Angie watching the stars for half an hour before going to bed. Saw two shooting stars.

Day 3

Turning a wheel,
Moves the wax,
Cuts a groove,
Which before it lacks.

Sound falls on cone,
Is transferred to needle,
Its motion on the groove,
Records sounds of people.

Back to the start,
Our groove and needle,
Replays the sound,
If ever so feeble!

Yesterday the tin can and nail recorder didn't work. Spent hours yesterday making up a sound box to go on the metal cone. Made a versatile unit to test out lots of diaphragms. Also tried plastic, sheet metal, wood etc. The next step today was to fix this larger cone in place onto the apparatus. Had to make up a wooden hinge with a screw mechanism to fine-tune the position of the needle onto the wax - and take the weight - reproducibly.

On one of the test runs, which was filmed, it really worked! It was a wonderful moment especially as I had not expected it to work on the wax alone. I thought that we might have to cover the wax in a thin layer of aluminium foil to get it to work.

Went on to try out thin layers of foil but my cylinder moved around too much and every so often the needle tore the foil! We need several days' work to get it to function properly and this was our last day. Angie made some major suggestions along the way, such as the need for the hinge, and that the needle had to be bent slightly so that it points away from the direction of travel of the cylinder (so that it has less tendency to dig into the wax).

I shouted "One, Two, Three BOOM" into the cone and on playback we got "Un, ou, fee, oom"! Just audible - it was really great.

As a grand finale we got Kate, Ellen and Kathy to shout "ONE, TWO, THREE, ROUGH SCIENCE" into the cone but I couldn't get anything recorded on those tries (even after my ears had stopped ringing!). I reckon that one in a hundred tries would have worked with the wax and we managed to catch one live on TV - that's jammy!