The Go A.P.E. Aural Piano Tuning System is the most Accurate, Precise, and Efficient Aural Piano Tuning System I have ever used, EVER!

There are three elements that make this system so powerful.

1. Beat Speed Windows.
When tuning notes, we tune them so that they produce a beat speed with another tuned note that relates to other already tuned intervals. Often these other intervals create a "window" - a pair of intervals that beat slow and fast - and the note we are tuning must produce a medium speed between the two already tuned intervals.

2. Double String Unison
This is tuning two strings as a clean unison and then judging the pitch. If we need to move the pitch, we move one string first. In this way we hear pitch changes as little as 0.5 cents.
This forces us to get good at tuning clean, stable unisons fast because without clean unisons, we can't hear the beats.

3. Non-Speaking Length (NSL) Tension Analysis
By knowing how tight we must leave the NSL, and knowing how to do that, we can analyze why our strings aren't stable and change our technique to fix it.

The videos below explain more about the method.