Poor Puccini - unworthy, according to some, of a place among BBC2's Great Composers. Do these critics have no heart? At least they have grown out of questioning Tchaikovsky's value (well, most of them). But they missed the really interesting cultural shift which Saturday's latest (and last) instalment showed when it turned to Gustav Mahler.

Naturally the programme itself had more immediate issues to deal with. It told the life with great succinctness, as it should have done given the bewildering procession of biographers that dominated the screen. Few composers have spawned more. They even included a "film biographer", as it flatteringly called Ken Russell. All men, they allowed Mahler's wife Alma to emerge as a fusion of groupie and helpmeet - nobody spelt out the fact that he required her to stop composing. Landscapes were stunning when they got a look in. Once again in this series, the music had to take bite-size treatment. Some spacious phrases which Charlotte Hellekant sang with intense concentration felt as hard-won as the moments of peace in Mahler's symphonies.

Only a couple of decades ago, this programme in this place would have been unthinkable. Public enthusiasm and a few musical champions had by then forced his recently out-of-copyright symphonies into concerts, and record companies were rapidly latching on. The expense of putting on the more extravagant of them began to look less daunting. But was he, well, respectable? Was he hell! In an interview for a postgraduate course, I was authoritatively told that analysing Mahler's music had no point because everything was on the surface. Never mind Schoenberg's patent respect. Suddenly the awestruck yet strangely defensive tone in which Berg used to write about Mahler began to make sense.

The point is: perceptions change, and it's never totally clear why. You can argue that people took note of Schoenberg's point of view, not least by realising that his own music is steeped in Mahler's influence. Then again, one generation passes and the next holds different values. Most of the BBC contributors belonged to the one that grew up accepting Mahler. It would be nicest to believe that constant exposure to the music finally allowed it to make its own case. Two composers who received Radio 3 airtime this week reinforce that belief.

Surely there is only one reason why the name of Henri Duparc is not constantly on everyone's lips. He left barely a couple of hours' music from a whole lifetime, chiefly songs, for which the audience is limited. Most of them featured in Monday night's Voices and inspired the usual awe from presenter and accompanist Iain Burnside and, doubtless, from listeners. Like all "great" poets as well as composers he made a particular kind of sensibility uniquely his own. The songs exist in a drugged or erotic stasis with outbursts of passion: "luxe, calme et volupte" as Baudelaire put it in the text of a famous Duparc song.

Here is a fine candidate for the next BBC2 series, if it can let itself supply the exposure that would enlarge the following. No other composer, except perhaps the similarly unprolific Paul Dukas, sustains such completeness and perfection through an entire uvre, small as it may be.

Meanwhile Radio 3 has been doing its best for another candidate's cause. This was Bohuslav Martinu, the emigre Czech who took up a Composer of the Week run as well as a whole weekend of public concerts in London.

As with Mahler, the idea would have been scorned not long ago. The same professor who made light of my interest in the one was positively amused when I asked about studying the other. Since the university had little material about him anyway, the point could not then be put to the test. Nowadays it looks as if the problem was the opposite of Duparc's: prolific, therefore slapdash, was his image. Slapdash and rare performances might have been the real obstacle.

In Martinu's case, the special character has much to do with precision. Without that, the special energy and intensity do not have a chance. Supply it, and almost any one of his extensive catalogue of works can cause fresh listeners to experience bouts of excited devotion. If I were predicting the shortlist for the next generation's "Great Composers" series, 20 years on, I'd bet he will be there.

Robert Maycock