Is the Scottish Chamber Orchestra the most versatile of Scotland's national orchestras? Is the SCO the most undervalued of Scotland's orchestras? Is the SCO the most technically accomplished orchestra in the country?

All three questions lead directly into a minefield for music critics, commentators and pundits. That minefield has clear warning signs which, bitter experience in the last quarter century has taught me, should wisely be observed. Attempt any comparison between the three Scottish orchestras (RSNO, BBC SSO and SCO) at your peril.

There is a school of thought, to which many members of these orchestras belong, which says that any comparison is spurious, that all the players in the orchestras belong to one community, they all know each other, some of them live with each other, none is less well-trained than any other and indeed they pop up periodically in each others' bands, cross-fertilising, as it were, the individual orchestras.

Fair enough. But they don't all sound the same. It's not comparing like with like. Each is a different size, each has a different character, each has a distinctive musical sound and each is susceptible to circumstances, whether that is the current political and financial health of the orchestra, or the quality and ability of the conductor standing in front of them.

One major difference between the three national orchestras is this. Only two of them ever hit the headlines and become a focal point for musical, and other, opinion in Scotland.

Both the RSNO and BBC SSO, at various points in their history, have commanded attention beyond the limits of their own concert hall audience. The news might have been good; it might have been bad. Whatever, at critical moments there is a machine that goes into action that projects the orchestra into a wider field of perception than is usual.

Look at the RSNO developments in the last two years, since the appointment of Stephane Deneve as principal conductor and music director, along with the appointment of his new chief executive, Simon Woods, who has driven a coach and horses through the perceived profile of the big symphony orchestra.

With the BBC SSO, look no further than the last few weeks following the splashy announcement of the appointment of Donald Runnicles as its new chief conductor from 2009. It is the talk of the steamie at the moment, and will remain so for the next two years until the star conductor takes up his post. And this is the band, don't forget, that, 25 years ago, time forgot and the BBC wished didn't exist.

So what of the SCO? Go on, tell me the last time they were in the serious limelight. When did they last make the headlines? When was the last occasion at which the SCO chairman or chief executive made an important pronouncement about their organisation?

And, let's be brutally frank: when was the last time you had to queue at the box office, far less round the block, to get a ticket for an SCO concert? Indeed, when was the last time you overheard or participated in one of those animated pub or street conversations where folk raved about the world-class orchestra that played weekly on their doorstep?

The phenomenal versatility of the SCO, though famed among those who know, is insufficiently recognised. Look at their current track record. At the end of last month they were playing music at their home base of the Queen's Hall in Edinburgh and at the City Hall in Glasgow by leading American composer John Adams and the great Polish composer Witold Lutoslawski.

Within a fortnight they were ploughing into symphony orchestra territory with an all-Sibelius concert. A week later, the superlative woodwind section launched a new series on Edinburgh with an outstanding performance of Mozart's Serenade for 13 Wind Instruments. That same week, the full band was in the repertoire heartland with Haydn and Beethoven.

This week they are at the boundary crossing between Classical and Romantic periods with an all-Mendelssohn programme directed by the venerable early-music guru Frans Bruggen. In a few weeks' time they will be deep in the Romantic mire with music by Puccini, Chopin and Schumann. Then, within a week of that, they will be playing folk-influenced music from Eastern Europe and jazz-influenced modern music, including a new work written for jazz bassist extraordinaire John Patitucci.

The range is staggering, and, following their regular form, nothing less is expected from the SCO than a level and variety of virtuoso playing absolutely appropriate to the demands of each individual piece.

To put it bluntly, in terms of the breadth of their repertoire, and the plurality of playing styles they can exercise across that breadth, there is not a band in the land that can hold a candle to the SCO. That is not a criticism of the other orchestras. It is simply a statement of fact.

And such is the intimacy and needle-sharp acuity of communication between the players in the 37-strong orchestra that, if they are unfortunate enough to end up with a duff conductor waving a white stick ineffectively at them, they will just watch and listen to each other and produce the goods themselves.

I've heard them play all over the world, from sun-kissed Bermuda to the awesome bustle of the Japanese touring circuit. They are without parallel. They are a wonderful band, world-class, as was observed privately by a senior and respected London music critic at an SCO Edinburgh Festival performance. So why are they not trumpeted and feted at home? Why is the very mention of their name not synonymous with greatness?

Why are their concerts not automatic sell-outs?

It's the house style of the orchestra, admits SCO chief executive Roy McEwan, a quiet Borders man, soft-spoken, measured and largely imperturbable (even if he can never fully forgive me for being instrumental in screwing up his band's close association with the composer James MacMillan).

"We do sometimes under-sell ourselves, and we do soul-search about it. It's become part of our style, and it's not easy to break out of.

"It has its advantages, in a way. We never over-sell ourselves, and we don't say things about ourselves which are not actually true."

It's a house style he inherited some 15 years ago when he took over, he says, and it extends throughout the organisation, including its discreet but phenomenally effective chairman Donald MacDonald.

"My perception is that the SCO was always enterprising and pragmatic, and always had in mind an end-result of excellence, but not one that was self-important. It was not pompous, which is one of the biggest crimes.

"That said, maybe we do bend over backwards too much. Maybe we do under-sell ourselves. Maybe we should jump up and down a bit more. But doing things quietly quite often yields its own benefits and we are just careful about our integrity and making sure that what we say we do, we deliver."

  • The SCO plays Mendelssohn, tonight at Younger Hall, St Andrews, 7.30pm. Tomorrow, they play The Queen's Hall, Edinburgh, 7.30pm. On Friday, they will be at City Hall, Glasgow, 7.30pm.