It is always interesting when listening to works recorded over a period of years to try and detect changes that may have taken place in instruments or surroundings. On this occasion you will have to allow both myself and David Fanning (who reviewed the LPs) this little indulgence for a series stretching from April 1981 to September 1983. In the event, the differences prove to be small, small enough to pass unnoticed to many ears. Wisely, those responsible for recording these works (in Switzerland) chose largely to exclude the encircling ambience by adopting a fairly close pick up, so that the reproduced sound takes up the ambience of the listener's room. Thus, one can readily adjust the volume to give a natural level so that these two distinguished players might well be performing in that room. In so doing one can shift one's attention to either partner at will. Having done this once, it is rather annoying to find that moving to another recording period requires one to carry out a reassessment and make some adjustment to restore the status quo.
It is hard to tell if the same piano was used throughout, certainly the 1981 recordings have a harder and more dominant character and the pedalling seems more obvious. However, it is very unlikely that any listener would wish to sit through the whole four hours involved at a single hearing and these details are then of little relevance.'