Some orchestras tune using an electronic tone generator. When playing with fixed-pitch instruments such as the piano, the orchestra will generally tune to them—a piano will normally have been tuned to the orchestra's normal pitch. 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. Some orchestras like the Berlin Philharmonic now use a slightly lower pitch (443 Hz) than their highest previous standard (445 Hz). Many modern ensembles which specialize in the performance of Baroque music have agreed on a standard of A = 415 Hz. An exact equal-tempered semitone lower than 440 Hz would be 415.30 Hz; this is rounded to the nearest integer. In principle this allows for playing along with modern fixed-pitch instruments if their parts are transposed down a semitone. It is, however, common performance practice, especially in the German Baroque idiom, to tune certain works to , approximately a semitone higher than 440 Hz (460–470 Hz) (e.g., Pre-Leipzig period cantatas of Bach). Orchestras in Cuba typically use A436 as the pitch so that strings, which are difficult to obtain, last longer. In 2015 American pianist Simone Dinnerstein brought attention to this issue and later traveled to Cuba with strings donated by friends. Particularly in the beginning of the 21st century, many websites and online videos have been published arguing for the adoption of the 432 Hz tuning instead of the predominant 440 Hz. These claims also include conspiracy theories related to Nazis having favored the 440 Hz tuning.