According to Classic FM’s managing director Darren Henley there are many people who find the term “chamber music” offputting, if not downright intimidating. Perhaps the best explanation of the genre comes from a musicologist who has termed it “the music of friends”. It’s a lovely description and one that, for the very best ensembles, can extend beyond the confines of quartets or duos to even the largest of symphony orchestras.

We are still acknowledging our 21st-century debts to the energy, curiosity, determination and passion for discovery of a host of Victorian polymaths, and here is another. Sir Charles Eastlake (1793-1865) was a painter, scholar, author, collector and translator – fluent in German, French, Italian – and the first director of the National Gallery, rising above disputes with trustees and the government to set the scene for the role it plays today.

This week's chronologically varied selection includes instrumental music written by one of the giants of Elizabethan music and a baffling, beguiling work composed by a 20th-century maverick, inspired by a visit to a Japanese garden. There's also a splendid new recording of an Italian opera which opens with one of the world's most famous tunes.

Who could argue that television isn’t a great medium for learning about art? In its pared-down, visually literate way it delivers what dull, theory-laden extrapolations often can’t (if only because artists don’t think that way when they make things, and we don’t think that way when we look at things). It can breathe renewed life and vigour into a subject we think we know well, and, as a medium for simplified, pocket-sized information, it can get straight to the heart of a matter. Perfect. Possibly. And so we come to The Impressionists: Painting and Revolution.

For so many days a year, Cheltenham's Regency symmetry and conservative values totter and buckle as they veer dangerously towards relative festive liberalism. As I sliced into one of the four annual beanfeasts, the Cheltenham Music Festival, it struck me how well lopsided, sometimes painful bendings of a classical framework by Schumann and Brahms sat with a battery of volatile percussion celebrating Steve Reich's 75th birthday. Even the adventure served up by trebles over in Norman and medieval Tewkesbury glimpsed a beast in the jungle.

This week’s reviews include a generous Liszt anthology played by one of the 20th century’s most fondly remembered pianists. There’s a reissued box of Beethoven symphonies performed on modern instruments by one of the classiest European orchestras. Heading further north, we've a repackaged set of Sibelius symphonies with some essential extras.

With opera houses in Britain now ringing to the four-letter cries of Anna Nicole and Two Boys (not to mention the rather more elderly, but no less explicit utterances of Le grand macabre) verbal taboos it seems are a thing of the past. Yet one word remains tainted, perpetually and immutably filthy, never to be voiced in polite cultural company: operetta. Whether or not Puccini’s La rondine actually falls into this genre is debatable, but like the heroine at its heart we shouldn’t allow this silken embrace of a work to be tarnished by a label, however obscene.

Shared Experience is certainly living up to its name; in a radical departure from normal theatre conventions, the company is currently sharing part of its rehearsal process with audiences as it develops Helen Edmundson’s latest work, Mary Shelley, which tells the astonishing story of how Shelley came to write Frankenstein at the age of only 18.

An unreleased live recording from a much missed conductor provides heartwarming food for the soul, while another podium giant brings musicality to uncompromising Modernism, aided by a phenomenal pianist. Meanwhile, a Hungarian exile in Hollywood takes a break from composing film scores and thinks of home.