It should be noted too that pitch inflation is a problem only where musical compositions are fixed by notation. The combination of numerous wind instruments and notated music has therefore restricted pitch inflation almost entirely to the Western tradition.
On at least two occasions, pitch inflation has become so severe that reform became needed. At the beginning of the 17th century, Michael Praetorius reported in his encyclopedic Syntagma musicum that pitch levels had become so high that singers were experiencing severe throat strain and lutenists and viol players were complaining of snapped strings. The standard voice ranges he cites show that the pitch level of his time, at least in the part of Germany where he lived, was at least a minor third higher than today's. Solutions to this problem were sporadic and local, but generally involved the establishment of separate standards for voice and organ ("Chorton") and for chamber ensembles ("Kammerton"). Where the two were combined, as for example in a cantata, the singers and instrumentalists might perform from music written in different keys. This system kept pitch inflation at bay for some two centuries.
Despite such confusion, A = 440 Hz is arguably the most common tuning used around the world. Many, though certainly not all, prominent orchestras in the United States and United Kingdom adhere to this standard as concert pitch. In other countries, however, higher pitches have become the norm: A = 442 Hz is common in certain continental European and American orchestras (the Boston symphony being the best-known example), while A = 445 Hz is heard in Germany, Austria, and China.
In practice, as orchestras still tune to a note given out by the oboe, rather than to an electronic tuning device (which would be more reliable), and as the oboist may not have used such a device to tune in the first place, there is still some variance in the exact pitch used. Solo instruments such as the piano (which an orchestra may tune to if they are playing together) are also not universally tuned to A = 440 Hz. Overall, it is thought that the general trend since the middle of the 20th century has been for standard pitch to rise, though it has been rising far more slowly than it has in the past.