David Taylor <[email protected]> wrote: > On 27/01/2013 19:33, unruh wrote: >> On 2013-01-27, [email protected] <[email protected]> wrote: > [] >>> In case you are wondering, my app is a professional piano tuning app. >>> The standard in this industry is that tuning devices should be >>> accurate to 12 parts per million. I know that is probably overkill >>> for tuning pianos, but that is what the professionals expect from >>> their equipment. >> >> Ah. I would expect 1 cent, which is more like 500PPM. > > 1% (10,000 ppm) is a 4.4 cycles per second beat at 440 Hz! Completely > unacceptable. You want an imperceptible beat, ideally, well under 1 Hz. > Agreed that 12 ppm is overkill.
The general rule of thumb for metrology is that your instrument should be at least an order of magnitude better than the allowable error, i.e. if your allowed error is 1%, your instrument should be capable of measuring to an accuracy of at least 0.1% for the measurement to be meaningful. _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
