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I turned on a spectrum analyzer and played the A string, tuned to 440hz, and harmonics (I guess) seem to be way louder then the actual note played.

Is this normal? I was hoping to be able to see in real time what I am playing.

Could anyone please give me some guidelines so I can read about this, possibly fix the cause, assuming there's a problem here?

Why is A2 (110 Hz) the strongest?

harmonics

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  • Why do you assume that there is a problem with your guitar if you didn't hear it before you connect the analyzer? What where you trying to do in the first place?
    – Chris
    Commented Mar 13, 2015 at 19:54
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    The guitar works and sounds great, there is no problems. I am just trying to gain deeper understanding of what's going on, just for the fun of it. I thought the A (fifth string) was 440Hz, and am really surprised by seeing this.
    – cab00t
    Commented Mar 13, 2015 at 20:00

2 Answers 2

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You might be actually playing A 110, two octaves below A 440.

The open A string on a standard tuned guitar is actually two octaves below the A that is normally tuned to 440. To play the A that should be at 440 Hz, you have to play the 5th fret on the high E string, or the 10th on the B string, or the 14th on the G string, etc.

Why? The 440 A is the A above middle C, and the guitar is actually a transposing instrument, with notes sounding an octave lower than written. So if you see sheet music with note on the A above middle C (the second space from the bottom in the treble clef), then you should play the second fret of the G string, or the seventh fret of the D string, etc.

Notation wise that would be the 440 A, but you're only playing the 220 A because the actual frequencies the guitar puts out are an octave lower than written. That's a bit weird and technical but if you are playing the open A string, the fundamental frequency should be 110 Hz.

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    You got it. Here's a link to a great explanation of why the guitar transposes: answers.yahoo.com/question/index?qid=20100331192052AALjQd7
    – Todd Wilcox
    Commented Mar 13, 2015 at 20:15
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    Also, the "440" on a guitar tuner doesn't mean you're actually tuning your A string to 440 exactly, it just means that 440 is the reference frequency and all the notes you tune will be relative to that. Since the open A is two octaves below, choosing 440 on the tuner calibrates it to tune open A to 110. If you calibrated the tuner to 435, it would have you tune the open A to 108.75 Hz (435/4 - two octaves down).
    – Todd Wilcox
    Commented Mar 13, 2015 at 20:18
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    The 'harmonics' ARE the actual note played. Your string is putting out all those frequencies. The only way to eliminate that is to get a bandpass filter that allows only frequencies in a tight gap around 110 Hz. Unfortunately this will not be even close to an accurate reproduction of your guitar's sound.
    – Darren Ringer
    Commented Mar 14, 2015 at 0:25
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    I am seriously mind blown with this... Apparently this is timbre? The fact that the guitar has these specific harmonics / overtones? Should I call them harmonics or overtones?
    – cab00t
    Commented Mar 14, 2015 at 9:36
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    "A transposing instrument is a musical instrument whose music is notated at a pitch different from the pitch that actually sounds (concert pitch)." Based on that definition, the guitar is a transposing instrument. The note that you play on guitar when you read a middle C is NOT the same note as the note you play on a piano when you read middle C. I've never seen the octave treble clef used for guitar. If you did notate guitar music with the octave clef you might want to clarify that your intention is the player not transpose.
    – Todd Wilcox
    Commented Mar 16, 2015 at 11:45
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There's a longer discussion of harmonics and their effect on instrument tone that is somewhat relevant to the discussion here. All "real" instrument pitches will have elements of the fifth, octave, and higher harmonics. Only truly electronic instruments (e.g., synthesizers) will have more "pure" pitches, but the way that electronic tones are generated, they also use the harmonics to refine the tone of the note. The fifth string A (110) is the correct pitch for that string if A-440 is the reference for tuning. Also understand that the guitar is (like a piano) tuned more to equal temperament than just intonation (same as mallet percussion instruments, but the metallophones use A-442 as reference due to the different weight of harmonics), so at baseline, the pitch shown is correct. I recommend https://www.beyondmusictheory.org/the-harmonic-series/ as a good general reference for harmonic series (overtone series) and you may connect the dots to how this affects guitar harmonics and tone. If you really want a detailed discussion of harmonics, ask a French Horn player.

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