Nearly a year on from starting Bachtrack, we keep on finding ever more improbable concert venues. It transpires that the main Blüthner piano showroom, a short stone's throw away from the uber-posh offices in London's Berkeley Square, puts on concerts once a fortnight or so. The concerts are played by aspiring young musicians, they are "by invitation" (in other words, you have to get in touch with Blüthner and ask to be put on their mailing list), and they're free - including the glass or two of wine provided on the house. The whole thing is a pleasantly sociable occasion.

Guitar concertos aren't performed (or indeed written) very often, not least because of the ferocious difficulty of achieving any sort of reasonable balance between a full symphony orchestra and a single rather soft stringed instrument which can't generate a sustained note.

 Since we last wrote to you in September, we've been as busy as usual, with tons of good new stuff on the site.

This morning, Gramophone magazine is publishing a list of the world's top 20 orchestras, collating the views of some of the world's top music critics and journalists (including, of course, their own staff). It shouldn't surprise you to know that the Bachtrack concert finder has listings for seventeen out of the twenty – and no, we didn't just put them in because of Gramophone!

So use this page as a "smart guide" to the top 20 orchestras in the world, where you can click on each name to see concerts in which they're involved:

A quick trip over to the Early Music Festival today, held in the gorgeous surroundings of the Wren-architected Royal Naval College in Greenwich.

The exhibition was suitably packed with the expected collections of lutes, viols, cornets, crumhorns, harpsichords and more different flavours of recorders and flutes than you could imagine. Many of the instruments are simply beautiful: early music people seem to take the aesthetics of their instruments far more seriously than the rest of us.