What is a...Trill?

A trill is a short musical action, or 'ornament', whereby a musician quickly alternates between two notes; imagine a twittering bird...

Now this one's simple, isn’t it? A trill is one of those extended wobbles on a long note you tend to hear at the end of a show-off solo in a concerto or coloratura aria. In the Baroque or Classical eras it’s virtually a fixture.

Yes, the wobble must be on two notes – neighbouring notes to be precise (either a major or a minor second) – but surely that’s it.

Alas, no. Go back to the very early Baroque period (at this point regular readers of this column may be experiencing a slight anticipatory contraction of the stomach muscles), to the vocal works of Monteverdi and his contemporaries, and there you will find the word ‘trillo’ identified with something significantly different.

There it’s not so much a wobble as a shake, and on just one repeated note. The kind of trill described above is usually smooth, legato, but this one is jerkier, more like a vocal spasm.

The gorgeous ‘Duo Seraphim’ from Monteverdi’s Vespers contains plenty of these, as when the word ‘Sanctus’ becomes ‘Sa-ah-ha-ha-ha-ha-ha-ha-han-ctus’. When historically minded performers first revived this kind of trill, critics and listeners found it rather funny; now we’re used to it, it can be strangely touching or, even more strangely, erotic.

Nowadays we’d be inclined to call this a ‘tremolo’. Monteverdi would also have used the word ‘tremolo’, but what he meant by it would be what we would call a trill. At some stage during the 17th century, the two terms seem to have swapped over.

The sign for a trill is an italic tr followed by a wavy horizontal line, which for once looks very like what it represents, and perhaps for that reason it has remained standard since the early-18th century.

What it doesn’t tell you, however, is how to begin or end the trill. All sorts of exit strategies are possible. You can anticipate the final note by a fraction of a beat, or just drop onto it. You can preface the fall to the final note with an elegant downward twist or a breath-catching minute pause.

As for the beginning, unless indicated otherwise, the modern trill starts on the lower note; the high Baroque trill, however, began on the upper note. The change seems to have happened around 1830.

Not for the first time, I wonder if this was just a change in fashion, or whether there’s some deeper sociological significance. A possible subject for a thesis?

This article was first published in the December 2015 issue of BBC Music Magazine