I have even read things that imply that Mozart is widely considered to be inferior music ONLY suitable for this purpose, and not serious or "difficult" enough for fully-fledged musicians to pay any attention to.
As I am not personally fond of Mozart, I haven't played much of his music and thus don't feel qualified to judge whether it really IS less technically or emotionally demanding than that of other composers. However, it recently came to my attention that Bach is treated, by some, in much the same way: as excellent 'first concerto' material for children learning the piano, or (in the cases of the preludes and fugues) excellent exercise material, but not really of any worth to the experienced musician.
This horrifies me for a number of reasons. First, to suggest that anything Bach - possibly the greatest composer that ever lived - wrote has no musical worth is nothing short of blasphemy. I can hardly think of a great composer since Bach's time who has not, in some way, been influenced by his music. However, I hardly need that as an excuse for defending the excellence of his compositions. The main reason I'm offended by this devaluing, as it were, of Bach's music is because it implies that, like Mozart, playing Bach requires less technical skill or musical understanding than playing the music of other composers.
I've noticed a curious thing when I tell people (generally musicians or music lovers who aren't pianists) about the pieces I'm working on. The conversation usually goes something like this:
Me: 'I'm learning two concertos.'
Friend: 'Which ones?'
Me: 'Bach's D minor...'
Friend: *no reaction*
Me: '...and Rach 2.'
Friend: 'OOOH! That's one of the hardest concertos there is!' *impressed face*
Me: *mumbles something about Prok 2*
Misconceptions about hardest concertos aside, it seems like Rachmaninov universally holds the status of Serious Music, while Bach is...well...less serious music - even inferior music - in the eyes of many people. If I hadn't seen evidence of this attitude elsewhere, it would never have occured to me that people might think about Bach this way. Someone once told me they were surprised when they tried to play a Bach prelude and found it difficult. It strikes me as strange that people can listen to Bach and not hear the complexity of it.
To me, Bach has always been characterised by both outstanding complexity and technical difficulty; in the early music circle I grew up in, it was widely acknowledged that Bach was pretty much the hardest early music there was. But how does the technical difficulty of Bach compare to the music of the 19th and 20th centuries?
In Rach 2, most of the notes are for texture, and the few that form a melody are the ones that need to be brought out. This is usually achieved using the damper pedal and playing the textural notes lightly while the melody notes are played strongly. More often than not the 'textural' notes end up being drowned out by the orchestra anyway, and this combined with the concealing qualities of the pedal mean that you don't need to get every note right for the overall effect to be pleasant.
Since I like to actually hear all the notes, I strongly advocate NOT swamping them in pedal to hide technical inadequacies. The technique I describe above is one of things I find most frustating about modern pianists. But the fact remains that you can do that and get away with it, because romantic music was sort of written to be played like that. In fact, most of it is unplayable without a certain amount of pedal, although swamping is totally unnecessary if you are a good enough pianist (I could probably write a whole
On the other hand, under no circumstances will I resort to the pedal in Bach. It simply isn't in keeping with the sound I envisage for his music. I like a clean, percussive, articulated technique in Bach; it helps to emphasise the counterpoint and also makes the piano sound more like a harpsichord. But this clarity is a lot harder to achieve than the pedal-swamped passages found in romantic music. One wrong note in Rachmaninov might be barely noticable, but in Bach it could be a disaster. You can't fake it: every note is of equal importance (this is especially so in fugal passages, where each voice needs to be heard clearly.) Even if you do use the pedal (and thereby conceal half the notes, making wrong ones less apparent), the keyboard instruments Bach wrote for had a much lighter action than a modern piano, and so were much easier to play on. This made it possible to execute leaps and incredibly fast fingerwork that are awkward, to say the least, on a modern piano. When playing Bach on the piano, the performer often has to battle against the unwieldiness of an instrument for which the music was not designed.
Rach 2 is hard, and as soon as you introduce the concept of actually hearing all the notes, it gets much harder, because there are lots of them, and they are often very fast. But aside from one or two awkward passages (which can be glossed over with the pedal if necessary) most of the notes feel just right - so right that, once you've learnt them, they are not only easy, but actually physically pleasant to play. This can be attributed to Rachmaninov's own skill as a pianist, which enabled him to write music perfectly designed for the piano and the capabilities of the performer.
By all accounts, Bach was equally accomplished at the harpsichord, and no doubt his own concertos were similarly well-tailored to his instrument. Like Rach 2, the Bach concerto was never easy in the first place, but (if Bach's vocal works are anything to go by) it was probably written in such a way that once the keyboardist had learnt the notes, everything just flowed - at least, on a harpsichord, where the keys are much shallower than a piano's and only require about a quarter of the effort to depress. I actually have two harpsichords in my house, but they're both in such poor condition that I haven't been able to try playing the concerto on them (apart from the fact they don't have enough keys for the low notes; Bach must have had much bigger harpsichords.)
In the end, it's hard to draw a comparison, because the technique required to play Bach is so different from that required to play Rachmaninov.* All things considered, the two pieces are probably at around the same level of difficulty. This alone would probably surprise a lot of people. However, I'm finding the concerto that was written for the instrument I'm playing it on, regardless of the number of notes, is actually easier to execute successfully. Meanwhile, I've just started learning the last movement of the Bach concerto, and for the first time since I undertook learning these two concertos, I'm really struggling. I haven't started on the last movement of Rach 2 yet, and I'm fairly certain it's going to be the hardest. Will it be harder than the corresponding movement of the Bach? Even I would feel silly if I said it wasn't, but only time will tell!
*I have encountered pianists who fully appreciate the technical challenges of Bach, and even go so far as to admit they can't play it. These are accomplished musicians who have no trouble executing extremely difficult 19th and 20th century music, which demonstrates just how different the necessary technique is.