HE MAY have been dead for 63 years, but Sergei Rachmaninov — the Russian composer and one of the greatest pianists of all time — will be playing again in the concert hall.

He is among some of the greatest musicians of the past century whose sounds are being brought back from the grave. Classical and jazz geniuses, from Glenn Gould and Alfred Cortot to Art Tatum and Fats Waller, will be heard as if they are playing today — live, thanks to groundbreaking technology.

Mono recordings plagued by the problems of early records — the hiss and crackle of surface noise, scratches and sounds badly filtered through primitive microphones — are being transformed by the new technique.

Recordings of past piano masters can be difficult to listen to with modern ears that are accustomed to high-quality audio reproduction, and most experts have been taken aback by the rejuvenated music.

Tests conducted so far include a concert “performance” by the legendary Cortot, who died in 1962, of the Chopin Prelude No 3 in G major. The stage lights came up on a grand piano. No one was sitting at the keyboard, but the keys rose and fell as they did when he performed the piece.

Experts were astonished by the results after hearing his gentle touch, his luminous tone, even his mistakes, such as the light brushing of an extra note in one passage. The performance was a note-perfect rendition of the pianist’s original with the sound quality of 2006.

The technology allows historic recordings to be cleaned up and programmed into a computerised grand piano that will play exactly what the masters played. Their performances can be replicated so that every note they struck, down to the velocity of the hammer, is transcribed and encoded by a computer before being played back on a Yamaha Disklavier, a concert grand piano.

The sound waves in piano recordings are analysed and converted into precise descriptions of the keystrokes. Precision sensors operate the keys, hammers, dampers and pedals — mimicking everything to a fraction of a second.

Max Harrison, author of a book on Rachmaninov’s life, works and recordings, described the new technology as “an ingenious idea”.

This is a chance to hear Rachmaninov as his original audiences heard him. The Russian frequently appeared on the concert stage in London, Manchester and Edinburgh in the 1920s and 1930s, astounding audiences with his formidable technique.

The technology has been developed by Zenph Studios, a software company based in Raleigh, North Carolina. Its head is John Q. Walker, a musician and scientist, who was a leading developer of VoIP, the system that allows phone calls on the internet. Dr Walker, who was taught the piano by Rachmaninov’s last pupil, Ruth Slenczynska, said that when the historic records were made, the engineers of the day were using the best equipment available: “But the listener is 50 or 100 years in the future.”

Concert dates have yet to be booked, but the first recordings will be released in Britain next year. Until then, readers of The Times can visit timesonline to hear a 50-second “before and after” demonstration recording of Cortot in 1926.

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