Tuner

[Zero999]

I'm not sure what you mean but no, it won't work with chords, if a chord is played, the loudest note will be counted.

I wondered what would happen if both of the two notes are exactly the same amplitude so I did a simulation and if it's positive edge triggered, the lowest frequency is counted, if it's negative edge triggered the highest frequency is counted.

The phase also makes a difference as to which signal is counted, if the low frequency signal is shifted by between 90^o and <180^o and positive edge triggering is used, the highest frequency is counted, a phase shift of under 90^o and the lowest frequency is counted.

I suppose this means that in reality, the result will be unpredictable: with a chord you could get either note.

[scrat]

The note is the first harmonic played, so you have to detect which that. If your algorithm takes the higher order harmonic, you could be able to detect this, since it is too high, and you could still detect if it is tuned or not (if it is a 2nd, 4th or 8th harmonic it is one or more octaves below, but still the same note).

[Zero999]

The note is the first harmonic played, so you have to detect which that. If your algorithm takes the higher order harmonic, you could be able to detect this, since it is too high, and you could still detect if it is tuned or not (if it is a 2nd, 4th or 8th harmonic it is one or more octaves below, but still the same note).

I think you've missed my point: a chord is more than one note being played simultaneously, so which one will it detect? Whether the highest or lowest is detected depends on the amplitude and phase of the notes, so it will be unpredictable.

[scrat]

The note is the first harmonic played, so you have to detect which that. If your algorithm takes the higher order harmonic, you could be able to detect this, since it is too high, and you could still detect if it is tuned or not (if it is a 2nd, 4th or 8th harmonic it is one or more octaves below, but still the same note).

I think you've missed my point: a chord is more than one note being played simultaneously, so which one will it detect? Whether the highest or lowest is detected depends on the amplitude and phase of the notes, so it will be unpredictable.

That's true, but since harmonics are (by definition) at frequencies multiple of the fundamental, it could be not a problem if you lock to an harmonic. I make an example: you play a LA (440Hz), but it has also 2nd and 4th harmonics. They're still LA, respectively one and two octaves above. If you detect one of those harmonics and tune the instrument, it will still be tuned right, since all of the harmonics move together and if and only if the 2nd harmonic is tuned to be 880Hz (or the 4th to 1760Hz) the fundamental is right. The real trouble could be for other harmonics (3rd, 5th,6th, or other not-power-of-two), since you can confuse them with other notes. However, if you tell your tuner which note you will be playing, it will be easy to achieve tuning also in this case, unless the instrument is very much out of tune.