Guitar Tuner - Which harmonic?

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Guitar Tuner - Which harmonic? 2012-05-22T17:40:32+00:00 Let's assume I have an algorithm that can calculate the fundamental frequency of a plucked guitar string. Let's also assume that I know where the harmonics are and their individual levels. Now as we know the fundamental frequency level could be lower than the level of the harmonics, or in some cases almost non-existent. My algorithm can correctly detect roughly where the fundamental frequency should be. Here is an example of such a case. The E string on this bass guitar has the following typical measured frequencies and levels (these are course frequency measurements): Freq(Hz)_____Level(dB)___Note 40.75________-22.5________E1 82.28________-20.6________E2 123.9________-10.9________B2 Interestingly, most guitar tunes I tested incorrectly detects the above note as B2. As can be seen the 3rd harmonic has a level that is 11dB higher than that of the fundamental. Note that I can calculate a much more accurate frequency for any of the harmonics at a later point in my algorithm. That is not the problem. The problem is as follows... As I have discovered, the harmonics are usually *not* integer multiples of the fundamental. This is a know phenomenon. In my measurements, harmonics can be off by anything from 5 to 20 cents from the fundamental. So the question becomes, which one of the three different frequencies above should be used as the "true" pitch of the guitar? One would instinctively think it should be the fundamental frequency, however I'm starting to think it should be whichever is the most dominant harmonic since it will probably mask the other frequencies. Put another way, I'm guessing that we as people will use the B2 above as the true reference of whether the string is in tune or not simply because it is so overwhelming the other notes. Although note that due to how we interpret the harmonic relationships, we would still hear it as an E1 note regardless of how low the E1 level is. Does anyone know which would be the most "correct" frequency to reference for the true "pitch" as perceived by humans in the above example? BitFlipper https://www.kvraudio.com/forum/memberlist.php?mode=viewprofile&u=6646

pj geerlings pj geerlings https://www.kvraudio.com/forum/memberlist.php?mode=viewprofile&u=10706: KVRian; 911 posts since 1 Dec, 2003 from tejas

Post by pj geerlings » Thu May 24, 2012 6:30 pm

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The harder you hit a guitar string the more sharp is the initial pitch
For nominal hits the sharpness is not an issue
For tuning purposes you are forced to assume that the player is hitting the string with the same intensity as during a normal perfomance
peace y'all
pj

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