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When adding vibrato to a fretted note on an electric guitar, if I do so by bending the note up a semitone, I perceive as the pitch of the original note being modulated. When applying vibrato to a bend however I sort of bend up to the note from the semitone below but this I hear it as the sound of the higher pitch being modulated, despite it technically being the same as the pitch I'm not hearing in the original case.

I thought it might be my brain latching onto the start point of the vibrato as you typically bend up to pitch then release but it seems to be the same if I just start from the semi tone down.

Is this just an ambiguous sound that forces my brain just pick the most likely interpretation? If so why does it always pick the same option?

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    If your vibrato is actually as wide as a semitone, then that's a very wide vibrato. Perhaps consider pulling it back a bit to more like a quarter tone or less. – Todd Wilcox Jan 16 '18 at 15:09
  • Is it actually true in general that the ear 'picks a note' to hear? – topo Reinstate Monica Jan 16 '18 at 17:12
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    @topomorto - given several slightly different frequencies to be happy with, I reckon our ears will accept the ones that are most in tune with the rest of what we listen to. Why would it latch on to something dissonant? Maybe that's one of the reasons I find it hard listening to coliatura opera singers... – Tim Jan 16 '18 at 17:25
  • @topomorto IIRC, it depends on the width and rate of the vibrato and different brains will have different responses. Some vibratos will be heard as a single note by 99% of listeners, while others will be heard as a wide pitch variation between two notes (almost like a trill if it's fast enough) by 99% of listeners. There is research on what makes a pitch a pitch and how our brains distinguish between pitch variation and vibrato. I don't have it to hand at this time. – Todd Wilcox Jan 16 '18 at 18:20
  • @Todd Wilcox thanks for the tip. I'll be sure to pass it on to Yngwie ;-) – Willbill Jan 17 '18 at 17:16
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I found an excerpt from a chapter written by Johan Sundberg in The Psychology of Music, a compilation of articles, presumably all related to psychoacoustics.

Here are some quotes and explanations:

Although F0 [the fundamental frequency of the note] varies regularly in such tones, the pitch we perceive is perfectly constant as long as the rate and extent of vibrato are kept within certain limits.

This means if a vibrato is too wide or too slow or too fast, it will not be perceived as vibrato of one note, but instead a fast glissando or glide back and forth. I doubt that human-generated vibrato is likely to ever be too fast, but electronic vibrato can easily be sped up to the point that it is actually frequency modulation that causes a dramatic change in timbre, as used in synthesizers.

Later:

Our conclusions are that the pitch of a vibrato tone is practically identical to the pitch of a vibrato-free tone with an F0 equal to the geometric mean of the F0 of the tone with vibrato.

That suggests that upwards vibrato from a fretted note should sound a bit sharp, and downwards vibrato from a bent note should sound a bit flat.

In your particular situation, you can't entirely trust your perception of pitch, because you are overly informed about how you're creating the sounds and therefore are susceptible to confirmation bias. By that I mean, you expect to hear a certain pitch and that can create the auditory illusion of hearing exactly the pitch you expect to hear.

That said, unless you're playing in an ensemble with other instruments that are playing the same nominal pitches as you, naive listeners are unlikely to notice the difference.

  • Great answer thank you. I don't think I have a good enough ear to perceiving the level of sharpness or flatness talked about here but its very interesting to know. On the glissando effect as vibrato widens, thinking about it it becomes very simular to how a piano player might use a trill. Experimenting a bit more on both instruments it does feel like it's just an ambiguous sounds that my ear is happy to hear either way as best suits the harmonic context. – Willbill Jan 23 '18 at 17:24
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Could be a few things. The note you hear is often the one you want to hear - in tune with the accompanying chord and relevant to the melody. If the vibrato stays a little longer on the higher/lower note, that's coming out as a more important pitch.

Somehow, we tend to hear a fluctuating note as the highest part. For that reason, we often play the note we want a fret lower than it should be, so that giving it a semitone vibrato, it gives us the right note to hear. We may even start that with the string bent to pitch - a cunning, but not easy move.

There's probably a limit to the amount a note can be stretched upwards before we become aware that something's out of tune, but I'm not party to it.

  • "For that reason, we often play the note we want a fret lower than it should be, so that giving it a semitone vibrato, it gives us the right note to hear" Can you think of any examples of this? I don't know if I've ever heard vibrato what wide. "There's probably a limit to the amount a note can be stretched upwards before we become aware that something's out of tune, but I'm not party to it" Yes, this is true, but vibrato is different because it's periodic and not a static alteration in frequency. – Todd Wilcox Jan 16 '18 at 15:40
  • @ToddWilcox - the vib. doesn't have to be that wide, it just needs the 'proper' note to be played on a bent string, a fret lower than normal, as then it can be bent to the 'right' note and a sort of 'backwards vib.' applied, if that makes sense. If the note played is on pitch using a bent string a fret below, the 'let down' can be as little or as large as you need, up to, obviously, a semitone max. I used to use the technique a lot, but don't play so much guitar at the moment. Dependant on style, a tone vib. is as much as I'd go, usually that's between, say, a P4 and P5; or b7 and octave. – Tim Jan 16 '18 at 16:26
  • I don't understand what you mean about vibrato "having to be wide". You've asserted that guitarists will play the note they want a fret lower than they otherwise would if they want to apply a wide vibrato to it because we allegedly prefer the highest note when vibrato is making the pitch ambiguous. I certainly don't know everything but I've never heard of any of that before, neither the higher note preference nor the guitar technique. I would like to know more about both so I was wondering if you could point me towards some sources for further reading. – Todd Wilcox Jan 16 '18 at 16:49
  • @ToddWilcox - no, it doesn't have to be a wide vib. Imagine wanting a top string E, 12th fret. Press, play, vib. Fine. But another way would be to press fret 11 and bend so you play an E. That can have vib. applied by releasing slightly, or more, then bending back to original. So now, the pitch at its highest, is the note you want to play, rather than the note you want to play bending upwards to produce vib. No reading material, sorry. Just started using it when teaching different vibs years ago. Give it a try, it makes sense when it's happening, although maybe it sounds weird. – Tim Jan 16 '18 at 16:57
  • I've done tons of bent vibrato. Because whether you bend a note or not, if you're sticking to it, you often want vibrato. But let's leave that aside. What about the question of whether the highest frequency heard by the ear during a wide vibrato is preferred by the brain when determining what pitch is being played? I'm very interested in that and I think it cuts right to the heart of what this question is about. How does the brain choose a pitch when it is technically being presented with several nearby frequencies in rapid succession? – Todd Wilcox Jan 16 '18 at 17:05

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