How can innovation build on innovation? How do you know when your innovation is 'right', and for that matter how do you know when the original innovation that you’re innovating on top of is also 'right'?

As the Artistic Director of the MultiPiano Ensemble, a rare kind of group, made up of a modular combination of pianists dedicated to expanding the horizons and exploring the possibilities of the tradition of muti-hand piano playing, I look for projects based on that vision. Sometimes, as on our new album for Naxos, that means creating new versions of existing compositions, that have a logical reason to be created anew for this ensemble. On this album we created new – and now officially approved – versions of works by two of the most innovative composers. It’s a not-simple, but fascinating and satisfying process!

So. The first idea I had was around Frank Martin’s remarkable Petite symphonie concertante for harp, harpsichord, piano and two string orchestras. It’s seldom performed. But I knew it well, because this work is rooted in a childhood memory. My mother, Naomi Lev, was a keyboardist for the Jerusalem Symphony Orchestra, and took part in an historic performance of this work as harpsichordist. The legendary Felicja Blumenthal was the pianist and no less a figure than Krzysztof Penderewski conducted – a big event! In those days, children of the musicians were sometimes allowed on the stage during rehearsal. I remember being transported by the incredibly magical sounds of the composition from the rehearsals, but then in the concert, when I was sitting with the audience, it didn’t work, at least not to anywhere near the hypnotic effect I had experienced sitting on the stage. This highly unusual combination of instruments had been intoxicating when you sat in amongst it all, but from a conventional acoustic spot in the concert hall, it all seemed sorely lacking, in something.

Many years later, when we started MultiPiano, this memory came back to me. I looked again at the composition and fell in love all over again with the music, but I knew this was, in a way, a bit of an illusion. That it didn’t fully work in a concert hall. And I started to wonder – here is this incredible composition for three keyboard/string instruments, and I had an ensemble that could provide three keyboard instruments. Could some of the problems of the work be solved by giving it a new acoustical perspective?

The big moment was when I came across Frank Martin’s own quotation, 'I was convinced that this sonorous work, owing to its experimental nature and its unusual combination of instruments would be restricted in its performance ... I feared that it would remain an instrumental curiosity …' So Martin himself had created a version for orchestra only, with no solo instruments. But that hadn’t done the trick either, as the piece had lost some of what made it distinctive in the first place.

But the Martin note gave me legitimacy and the impetus to approach his publishers Universal Edition and the Frank Martin family and to discuss with them my idea of replacing the three solo instruments. To my delight they were not only open-minded, but even enthusiastic, because they also knew about this problem!

All systems go. Except – how do you avoid wrecking a flawed masterpiece? Let’s face it, the music itself, and I write this as an educated musician and a person who has been on stages for many years, is on a par with what Bartók famously achieved for strings, percussion and celesta, or any other supreme 20th century masterpiece. Here was the paradox, and the opportunity.

I didn’t touch the orchestral part, and I didn’t add a note to the overall texture of the soloists. What I did was mix and match the three solo parts, and play with registers. For instance, when you have a piano and a harpsichord conversing in the same register the sound is varied enough, but when you have pianos there isn’t enough colour differentiation, so you have to add another dimension and play with registers. By the same token, harpsichord and harp are very light in texture; piano is a massive sound by comparison, so I also had to split and reorganise, both to keep the differences etched between the instruments and to maintain the same sense of 'air' around the textures.

And that solved many of the issues with the original. All three soloists could now clearly be heard, which isn’t usually the case in live performances of the Martin, where the orchestra has to be very small so as not to overpower the harp and harpsichord, and the pianist cannot play with intensity for the same reason. So the whole thing is usually played on eggshells, where the piece is full of moments that are incredibly powerful and demand physical intensity. Now, with this new version, the orchestra and all three soloists are balanced and can express themselves so much more openly. And that creates new opportunities for dialogue between three equally strong instruments.

Because the complexity of what Martin created cannot be overestimated. He uses two string orchestras placed on two different sides of the stage, and the work is incredibly 'responsorial' for the musicians, an idea that he took from early Renaissance and Baroque music. At one moment, for instance, you have 13 different voices, five from each orchestra and the three soloists, simultaneously heard or in very dense dialogue between the two corners of the stage. It’s incredible, but it only works if you can hear it all very clearly!

There was, however, one spot where we didn’t find a solution until the last minute. In the middle adagio sestenuoso, which is really the spiritual core of the composition, the most moving and almost psychedelic heart of the work, we needed to recreate the spooky, plucked sounds of the harpsichord. Martin demands a very special sound for that heartstopping moment. Finally we hit upon the simplest of solutions. We put a pencil on the piano strings, and the vibrations of the pencil are reminiscent of the plucking sound of the harpsichord, so for just that moment we turned our instruments into ‘prepared pianos’!

And suddenly. Here was the work I remembered from sitting on the stage. The power, the energy, the almost paganistic and rhythmically provocative qualities that are hidden in this composition came flooding into the hall in so much more immediate a way. The listener is inside the music, inside the sonorities. As we performed it, I felt, in fact, and with some satisfaction, that we were allowing the listeners to ‘sit on the stage’.

The next adventure was around Shostakovich’s Concertino For Two Pianos. Shostakovich was influenced by the Baroque concerto grosso form and, after all, he called it a concertino. Except that concertinos usually have soloist parts and orchestral parts; but here is a concertino without orchestra. It’s not only an anomaly by its name, the music tells us very clearly that there are parts that have orchestral-like massive textures, and parts that are solo-like virtuoso textures. And they’re divided very systematically, between piano 1 and piano 2. Piano 1 is like the orchestra and piano 2 is like a soloist.

So this time, I added a string orchestra – the typical accompaniment to a concerto grosso. I gave all the ‘orchestral’ bits and gave them to the orchestra, and divided the solo bits between the two piano soloists to keep the sense of dialogue that Shostakovich had imagined, and here I added just a little, in a restrained way, so that two soloists are "busy" all the time and have interesting textures to work with.

As with the Martin, I went to the estate – in this case to Shostakovich’s widow, Irina Antonovna. She and I had a personal correspondence in which I explained my vision for moving Shostakovich’s musical experiment much closer to its ‘source’, as it were. I sent her the music and, happily, she approved of it.

So these two works, recorded with the Royal Philharmonic Orchestra under Dmitry Yablonsky, form the core of MultiPiano’s new album, alongside Poulenc’s famous Concerto for Two Pianos, and a newer work, Aryeh Levanon’s Land Of Four Languages. And for all my anguished questions which began this article, and which started this whole process, the answer always comes back to 'think outside of the box and – that word again – innovate. Of course, it calls for conscience, much research, a leap of faith. Above all, love. And hope...

The MultiPiano Ensemble’s new album 'Works For Piano And Orchestra' is released by Naxos (see here for details), and includes three world premieres - new versions of works by Frank Martin and Shostakovich, alongside Aryeh Levanon’s ‘Land Of Four Languages’ - and Poulenc’s Concerto for Two Pianos in D Minor.