Material matters for brass instruments

I suppose we all take our instruments for granted a little bit, we pick them up and blow them and a nice noise comes out (most of the time anyway!). But how much do we consider the materials we are producing this sound with.

We talk about “brass” instruments but what is brass? This was actually quite an interesting bit of research, as there is not just one type. Brass is an alloy of copper and zinc, and is used for several reasons, firstly it is quite straightforward to mould into the correct shape as it is quite malleable. This does though make it quite soft and vulnerable to damage, as evidenced by many dings and lacquer marks that appear after a while. It is probably the case that if an instrument doesn’t have some minor dings or dents then it isn’t being used enough! Secondly it is still the case that brass does create the best sound, although there are theories that bronze, silver or even stainless steel could produce an equally good sound, but this is questionable.

Even so there are different types of alloys, with different proportions of copper to zinc. Yellow brass has a lower copper content and consequently more zinc, typically 60-70% copper, and produces a bright, sharp sound ideally suited to jazz instruments, standard gold bells have more copper, typically 70-80% and rose brass which has the highest content and the rounder, richer sound.

The finish is also important, many instruments nowadays are lacquer, a clear varnish which helps to protect the instrument from the elements, although most instruments will suffer some damage where the hands and fingers are in contact with the instrument. Silver plate is also used, but the process is more expensive than lacquer and it produces a more robust sound, but it does offer more protection against erosion.

And then of course there is a more modern medium which has become very popular, the plastic instrument. I must admit to some scepticism when they were first introduced, however since then my view has changed somewhat. The sound on these instruments is surprisingly good and a scout around YouTube illustrates this. There are also videos which compare the sound of plastic against metal and, although initially they sound remarkably similar, there are a couple of nuances which differentiate between the two. Firstly, the metal instrument has a more focussed sound which enables it to project better. Secondly, there are a much wider range of harmonics or overtones in the metal instrument, this leads to a brighter tone in the metal instruments and enables it to cut through the sound of other instruments. This is one of the downsides of the plastic instrument and one which makes it unsuitable for playing in an orchestra or band. It is unclear but the difference is probably more significant at louder volumes.

Undoubtedly, the biggest drawback with plastic trombones is the slide, which is made from carbon fibre. Now I know that it is possible to get it working reasonably well, some of the YouTube videos attest to that, however it should be considered how much work it takes to achieve that compared to applying slide cream or valve oil. For me, I never got it working very satisfactorily, and I understand that valves on trumpets and cornets also have their limitations.

So ultimately it comes down to a choice between metal or plastic, and for use in a group setting then there is probably no choice, the metal ones still produce a better sound which cuts through the rest of the group. However, plastic instruments are light and easy to transport, so for practicing when away from home they made be an option; they will take standard mouthpieces by the way and players do use metal mouthpieces with them. Their real value though lies in what they were originally designed to do, ie. to use in groups in schools where users may not be quite so careful and cause damage leading to ongoing repair costs. They are also relatively cheap to buy compared to their metal counterparts.

Finally, they are a bit of colourful fun as they are available in a range of bright colours, and when used in a group with other plastic instruments really come into their own. Fancy, a brass ensemble all played with plastic instruments.

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