Players of baroque instruments present masterpieces the way the composers would have heard them.

The figures in the posters on the walls of Music Room 3 at the University of Auckland's Epsom Campus celebrate luminaries of a bygone age. Four Liverpudlians - two dead now - who got about collectively as The Beatles; the great Jimi Hendrix, too, may he rest in peace, shyly smiling; a fresh-faced, bright-eyed bunch of Rolling Stones.

But the 15 musicians assembled in a horseshoe formation last Sunday afternoon were firmly focused on a time 250 years before Love Me Do. An interloper lucky enough to snare a seat at the side of the room was able to listen as 10 of them worked on the first movement of Bach's Brandenburg Concerto No3, or - later and at full strength - a persuasively chilly version of Winter, the last of Vivaldi's famous violin concerti collectively known as The Four Seasons.

These are among the most famous works of the Baroque repertoire, habitually hijacked by TV ads for banks and new cars - it can take a bit of effort to unshackle the association. But even to these untutored ears, there was something different about the sound on Sunday.

The reason for that is the ensemble's reason for being: NZ Barok, as it is called, plays these masterpieces the way their composers would have heard them.

Advertisement

That's accomplished by deduction based on exhaustive research, and by playing on instruments that are old (at least one in this room was already in service when Vivaldi and Bach sat down to write) or are made new-old: the designs, woods, resins, glues and techniques are those in use 300 years ago and the strings are made of sheep gut rather than synthetic or steel.

Some differences are subtle: the angle of a violin's neck changed to increase volume when performances moved from salons to concert halls. But some are more obvious: the so-called "swan-bill" bows, typically made of snakewood, look more like an archer's weapon than the modern axe-head bow and, by tapering towards the tip, have a built-in volume control. More noticeably still, violins and violas don't have chin rests and the cellists, without a spike, clasp their instruments between their thighs to hold them at the right height.

"Sometimes, I think we deserve danger money," says the orchestra's co-director Miranda Hutton, as she shows me how hard it is to slide the hand down the instrument's neck when it is not anchored under the chin.

The cumulative effect of all these differences is striking. Hutton tells me that, in contrast to its singing classical counterpart, the baroque violin has a speaking voice.

It's not a metaphor that suggested itself to me.

The sound filling the room seemed richer than that of string orchestras I've heard, and had a freshness and exuberance about it, as of something newly made.

"It's a real passion for us, to play the music as the composer intended it and would have heard it," says Hutton. "When you really get into it you hear this wonderful lightness and dance sound. The instruments really bring it to life."

The concertmaster, Ryo Terakado, explains during a tea break that a violin is always a violin. "Of all the instruments the violin is the least changed, because it was already perfect when they invented it.

"But playing baroque violin is like starting again. The gut strings react so differently. It's like you have learned to walk, now do a tightrope."

Now in its 11th year, NZ Barok (the spelling reflects the fact that many of the players have trained in the Netherlands, a mecca of the early-music revival last century) is the country's only baroque orchestra.

One of the world's leading baroque violinists, Brussels-based Terakado is in the country to lead the orchestra in concerts this weekend. But don't call him a conductor: the ensemble has no one in that new-fangled role because, as Hutton explains, that's how it was in Bach's day.

Instead, the group works collectively, cueing and watching each other, often with what seems like a sixth sense.

"In a symphony orchestra," says Hutton, "you are not allowed to speak.

"You have to shut up, do as you're told and have no thoughts of your own. In this, every person thinks independently and can contribute."

This collegial approach creates a light-hearted atmosphere.

When Terakado gently suggests a change in one violinist's technique, she winces self-deprecatingly.

"I know," she wails. "It sounds like a dog."

"What kind of dog?" a colleague asks.

"A dog that barks," deadpans Terakado.

NZ Barok plays in Hamilton on Friday and Auckland on Saturday and Sunday. www.nzbarok.org.nz