Why not buy a digital piano instead of a real one?

There is no reason why you should not buy a digital piano if that is precisely what you want, and you understand the differences between a digital piano and a real, acoustic piano. However, the digital piano, however good, is not something that replaces a real piano. A real piano is one musical instrument, whilst a digital piano is another. What are the most important differences?

Investment

Pianos, like most musical instruments, are known as a good investment. For the price of a good digital piano you could get a real, acoustic piano. Electronic technology of any kind is not likely to hold its value in the same way. Consider the value now, of any electronic equipment that is 10 or 20 years old. Many good, real pianos, if they have been properly maintained, are still recognised as good instruments today, and are in common use, 60 years or more after their manufacture. This makes them valuable.

Is this true of electronic equipment of any kind, including musical instruments? 

Modern or not modern?

The real piano is not something that is "out of date" compared to a digital piano. In fact, the investment stability of a good piano arises because the basic design of the piano does not change, nor does it need to change. From time to time certain "updating" innovations take place in the design of the piano, such as the use of a new material that fulfills a required function better. However, the simple fact is that piano cannot be wholly redesigned, and turned into a 21st century machine, or a new instrument, because if it were, it would no longer be a piano.

In past ages, musical instruments were re-designed and "evolved" into new instruments that simply replaced the old, as the world and music changed. That is how we got today's instruments. Today's musical world, however, is very different to the musical world of past ages. In the modern world, new instruments are invented, but invariably leave existing instruments intact and still in use. The electric guitar versus the classical guitar is one example. The electric violin versus the real violin is another. The modern piano remains basically an instrument of the 19th century, even if it now incorporates some materials that did not exist then (such as the delignite multilaminate wrest plank or pin block). This is not a drawback, but an intention.  

The piano is not supposed to change, any more than the violin or the trombone. The basic technological design concept used in the best new pianos today, is essentially the same as that found in the best pianos over 100 years ago. There is a limit to how far innovative changes to the design of the piano can be taken, without ostracizing the new design from the mainstream concept of the instrument. The piano today is unavoidably "protected" from changes beyond a certain degree, by the modern concept of performance practice. It is performance practice that keeps modern string players in the orchestra performing on what are fundamentally carefully crafted wooden boxes with strings, rather than on a "better", "updated", electronic invention. It is performance practice that keeps classical guitarists from throwing away the guitar and replacing it with an electric version. It is performance practice that keeps the piano from being replaced by an "evolutionary update", like the digital piano.

There is a truly vast repertoire of music written for the piano. Whilst one is free to play any music on any instrument, performance practice now keeps alive and relatively unchanged the instruments for which music was written. The digital piano, as an instrument in its own right, cannot claim an associated repertoire comparable to that of the real piano. It is unlikely that it will even exist in its present form a hundred years from now.

Digital emulation

Doesn't a good digital piano sound the same as a real piano?

You do not need to be an audiophile to experience the (rather obvious) difference. But if you have little experience in listening to piano music, and playing the piano, you may be easily convinced by the similarities.

People often say that the digital piano must be a good emulation because its notes are digitally sampled from real piano notes. Well, so are the piano notes on a modern, quality CD recording of a real piano. 

Do you know how much an audiophile would pay for a top of the range hi fi system that produced an experience as close as possible to having a piano in the room, when listening to a recording of a piano? Audiophiles might pay at least £20,000, or much more, for such a system. This price reflects state of the art speaker technology, and amplifier technology, etc.  For less, one could buy a grand piano. Are you about to pay a comparable price for a digital piano?

If the answer is "no", than you cannot expect it, seriously, to sound like the real thing in the room, just because the notes are digitally sampled. It will only sound as good as the instrument from which it has been sampled, as good as the recording technology, as good as the amplifier, and as good as the speaker technology in the digital piano.

Basically, digital piano notes sound like exactly what they are - recordings of piano notes played through rather mediocre equipment. If you heard, say, a Steinway model D side by side with the best digital piano, frankly, you would have to be at least partially deaf not to experience the difference.   

Horses for courses

The digital piano has a place. It's portable, and you can use it with headphones. If you are not playing classical repertoire or serious jazz, it might be the right horse for the course. But for an accomplished pianist, or anyone aspiring to become an accomplished pianist, it's not a serious substitute for the real thing.

Tuning - a question for specialists only

There is an interesting question associated with digital pianos, to which I do not yet have the answer.  Why do even the most expensive digital pianos seem to be sampled from instruments always containing some individual unisons that do not seem to be properly tuned? There are always some unisons on digital pianos in a condition that to me, as a professional tuner, seem to be absolutely demanding attention, either because they are not well tuned, or because there are very false strings. If it is falseness, then one would think if a manufacturer was going to sample a piano, he would choose one in perfect condition, without such an obvious degree of falseness. If it's poor tuning, what's the philosophy behind it? 

If it's neither, then the current process of sampling and reproducing is, unfortunately, highlighting tonally undesirable features of the soundscape.