A step by step method for tuning a piano aurally using beat speeds.
Each step of the way, this method gives you two beat speeds, that you have already set, and then you are required to set a third beat speed between the other two. This is the window method. No more guessing how fast the M6 has to be from the M3 in order to have an appropriate P4. This procedure gives you empirical limits that you can hear and measure. You can also use this procedure to check your progress, if you know how to measure beat speeds.