# Theoretical: Would it be possible to have a worldwide AC standard at 55hz

The question comes from a discussion I had years ago with a keyboard player who had perfect pitch. His problem came from the fact that he lived in a very small appartment in an old building and he had to play at a very quiet level. So quiet that he could hear the 60hz humm (we are in north america) coming from electric appliances and that would bug him a lot. He thought about it a lot and he realized that the electricity itself was actually out of tune. Since most modern occidental music is based the reference not of A=440Hz, if you go 3 octaves below that, you get to 55Hz. But AC around the world is either 60Hz or 50Hz. When he made that calculation, he declared that 55Hz would be a very convenient and musical average if there is ever a worldwide standard.

So here is the question. Is there a reason for 50 or 60 Hz? Or it might as well be 55Hz?

• Pretty sure it would be OK if it was 55 Hz. Note, this is theoretical. Like, if you go back in time to before there were standards, and convince everyone to adopt the 55 Hz standard. In the real world, changing to 55 Hz would cause a lot of problems for certain types of machines that rely on either 60 or 50 Hz. Especially induction motors and transformers. – mkeith Jun 14 '17 at 3:50
• Related (but not a duplicate): electronics.stackexchange.com/questions/310150/… – MarkU Jun 14 '17 at 3:51
• @MarkU : so from what they say there it's because of the induction motors that happened to work better at frequencies between 50 and 60Hz. So the answer would be yes, in theory, 55Hz would work too? – BadgerBadger Jun 14 '17 at 4:05
• I'm not convinced that a 55Hz hum (be it in tune with the standard scale) would be less annoying for music than a 60Hz hum. What about no hum at all? – dim Jun 14 '17 at 7:00