LET'S stick our heads under the bonnet for a moment this week and talk about something a little technical.

Worry not; I'm not going to attempt to baffle you with the science of four-part fugues with the second subject in inversion, or any such stuff. I'm going to witter on a bit about pedalling at the piano.

I can already hear the sniggers from the back of the keyboard lecture rooms in the Royal Conservatoire. You're quite right: what Michael Tumelty knows about the subtleties of pedalling at the keyboard could easily be filled in on the back of the proverbial postage stamp.

But what does interest me is the fact that, very recently, the great Hungarian pianist Andras Schiff, who knows a thing or three about all things pianistic, has said something extremely provocative and interesting. And what he was talking (or rather, writing) about was the subject of pedalling; specifically about ­pedalling in Beethoven's piano music. Before delving into his argument, a brief and crude word about the piano and the subject of pedalling for anyone or Everyman who might not have a piano to hand, nor any clue about music at all.

Decay is intrinsic to the sound of a piano. The piano is a percussion instrument. You press down a key, a hammer leaps forward and strikes a string, then retreats. The instant the string is struck and the note sounds, it begins to fade and decay. It's in the nature of the beast, and there is nothing on God's Earth (the real one, not the digital version) can be done to prevent that immediate decay of a sound.

What is possible is the creation of an apparent method of sustaining that sound and delaying, prolonging or extending its decay. Depress your key and put your right foot down on the right pedal. Keep it there and the sound will ring for longer, and fade more slowly.

What has happened is that the foot pedal, the sustaining pedal you have depressed, has raised a damper from the strings, leaving them to vibrate longer, and even set off sympathetic resonances in neighbouring or related strings.

Any pianist will tell you that the sustaining pedal has to be used judiciously and with great care. Keep it down too long as the music progresses, and the sustained sounds will blend, blur and confuse all manner of perspectives for your audience, whether you're pedalling through a melodic line or, particularly, through a set of ongoing and changing chords (harmonies). Composers usually indicate in their score where they want the pedal to be depressed, then raised, though in reality that can be as open to interpretation by pianists as any other aspect of notated music.

I don't know what modern educational thinking is, but in my day, a thousand years ago, you were telt to change (release) the pedal in line with the changing harmonies of the music, or you would risk harmonic congestion and blurring of the music. That's crudely expressed, but roughly the way it happened and still happens, in all keyboard music from Beethoven to Brahms and beyond.

Enter Andras Schiff, raging. He has just recorded a version of Beethoven's Olympian Diabelli Variations (actually, two versions on a double album, each using a different piano, itself an enthralling tale that will be reported here in the near future). Schiff has accessed Beethoven's original manuscript and come to the conclusion Beethoven "wants strange and alien harmonies to be joined together" by what some would consider over-pedalling (in other words, wrong pedalling instructions). The poor man was deaf, after all. But Beethoven, argues Schiff, knew exactly what he was doing, and that his pedal markings and instructions, and their consequent effects, are part of his compositional and creative DNA.

"We are all taught to alter the pedal at every single change of harmony. Incredibly, most pianists ignore Beethoven's instructions. To ignore them is the height of arrogance, a falsification of the music." Ouch. Food for thought there, and a ding-dong debate among professional pianists, I should imagine.