[1.III.14.8] That Unfamiliar Piano
Some students fret that the recital piano is a huge grand whereas they practice on a small upright. Fortunately, the larger pianos are easier to play than the smaller ones. Therefore the issue of a different piano is usually not something to worry about for the typical student recital. Larger pianos generally have better action, and both louder and softer sounds are easier to produce on them. In particular, grands are easier to play than uprights, especially for fast, difficult passages. Thus the only time you may have to be concerned about the piano is when the recital piano is decidedly inferior to your practice piano. The worst situation is the one in which your practice piano is a quality grand, but you must perform using a low quality upright. In that case, technically difficult pieces will be very difficult to play on the inferior piano and you may need to take that into account, for example, by playing at a slower tempo, or shortening or slowing down the trill, etc. The actions of grands can be slightly heavier than those of uprights, which may give some beginners problems. It is always advisable to practice on the recital piano.
Another important factor is the tuning of the piano. A piano in tune is easier to play than one out of tune. Therefore, it is a good idea to tune the recital piano just before the recital. Conversely, it is not a good idea to tune the practice piano just before the recital unless it is badly out of tune. If the recital piano is out of tune, it may be best to play slightly faster and louder than you intended.