The replica bells and cymbals – an update!

We have an update on the status of our metal instrument replicas! To recap, local Canterbury jeweller Justin Richardson is making replicas of a number of the metal  Roman bells and cymbals in the Petrie Museum, using alloys and manufacturing methods as close to the originals as possible. The aim is to play these replica instruments to reveal the sounds of Roman Egypt, and to see how different production methods and materials might have affected their sound. We recently met up with Justin to get a progress update.
Justin Richardson with some of the bell and cymbal replicas. Photo: Ellen Swift.
The process began with the 3D laser scanning of our selected objects – this data was used to make wax models which were then used to create casts in metal. This, along with sand-casting (discussed in our other blog post here), would have been the most common methods of casting metal in Roman Egypt.
There were however a few problems encountered along the way. Some of the objects we scanned created models where the walls of the bells and cymbals were very thin. This is because during their lives the surfaces of the instruments had worn down through use. However, this thinness resulted in castings that had large holes and with sections missing. We therefore had to edit our scanned models to increase the thickness of the instrument walls in places, thus ensuring a successful cast during the next attempt. This does however mean that the finished replicas will represent the instruments as they had been when new, rather than the older worn versions we now have in the museum collection.
The replica bells, cast using moulds made from the 3D models of the laser scanned originals. Photo: Ellen Swift.
Another challenge was presented by the clappers inside the bells – these are the articulated pieces of metal that cause the bell to ring when they touch the walls. The clappers could not be laser scanned as they moved around, and in a couple of examples were no longer extant at all. Instead we had to rely on what we could see by eye both in terms of style of clapper and material. It appears that both bronze and iron were used for clappers, with several different styles in use – therefore we have tried out a range of examples in the replica bells to reflect this. The cymbals also presented us with a range of different production techniques and materials. Brass, bronze, and copper are all represented, as are the techniques of both casting and hammering. For our replicas, there will be a pair made in spun brass, and a pair cast in bronze – this will allow us to see what kind of difference there is in sound quality.
One of the original Roman cymbals with a thinned wall (UC33268B). Photo: Ellen Swift.
 Justin and his team are now adding the final touches to the replicas. One of the bells had a ring that was originally gilded (as identified by the XRF analysis) so that element will also be replicated. The cymbals also need metal attachments added in the form of U-shaped metal handles. Finally, several of the bells were attached to metal bracelets, which are also being made. These bracelets are made of iron, but we cannot source iron of suitable dimensions to use for this. Instead Justin will be using steel, which is more difficult to work with than the original iron.
The bell that originally featured gilding – this decoration will also be included on the replica. Photo: Ellen Swift.

Once the replicas are completed, our next step is to create a recording off them being played. We will be using software that can mimic the acoustic qualities of any space, so we hope to replicate the sound of music as played in typical houses known archaeologically from Roman Egypt!

Bells, Cymbals, and Radiation

An important element of reconstructing musical instruments is making sure they are made out of the right stuff. In making our replicas of the bells, cymbals, pipes, and clappers in the Petrie Museum, we need to make sure we are using materials that are as close to those of the originals as possible – this gives us the best chance of ensuring that they will make the same sounds as the original artefacts. For example, the kind of alloy used in the cymbals will affect the resonance and tone of the sound they create when struck. So it is important to get it right! This is where compositional analysis (and a fair bit of science) comes in.

One of the cymbals selected for XRF analysis. Photo: Ellen Swift.

We have been using an XRF machine to find out exactly what our metal musical instruments are made of. The XRF (“X-Ray Fluorescence”) machine uses radiation to identify the elements present in an object; the x-rays cause the artefacts to emit radiation that is characteristic of its own elemental makeup, allowing the equipment to identify the component parts (if anyone wants a more scientific explanation, see here!). In the case of our metal artefacts, the XRF tells us exactly what the ratio of different metals were in each alloy used. All the bells and cymbals seemed to be variations of copper alloy, either towards brass (an alloy of copper and zinc) or bronze (an alloy of copper and tin) – however the compositional analysis has ensured we know exactly the ratios of these, and therefore can choose the most suitable modern alloy for the replicas.

The XRF machine in action at the Petrie. Photo: Jo Stoner.

The XRF machine is a fairly hefty bit of kit, thanks to the lead lined case that it comes with – this contains the object when exposed to the X-ray, and keeps us safe from the radiation. It is however portable enough for it to come up to the Petrie for a day’s worth of compositional analysis. To get accurate results, the objects need to have a clean surface – the artefacts in the Petrie are great for this as, by and large, they were thoroughly cleaned and conserved post-excavation, preserving their surface. Thus many of our readings were accurate enough to identify traces of gold, as well as the more usual bronze, brass, and iron, which suggests the presence of gilded surfaces now deteriorated and no longer visible to the eye.

The compositional analysis of this bell showed that it was originally gilded. Photo: Ellen Swift.

Now we have this data, we can undertake the next step – meeting with our replica makers to discuss the most appropriate alloys to use, as well as which manufacturing techniques should be used to ensure their authenticity.