Promoted from the comment stream, because I am a nerd and there’s a strong chance you might be, too.

Rosemary

In the comments for the previous post, “eub” said:

If I may geek on the tone doubling effect, was it a fairly consistent musical interval, or did the interval get smaller for higher pitches? Like a shift of X semitones, or of X Hertz? There is an uncommon drug effect that apparently sounds like a frequency shift (not a pitch shift), so harmonic sounds become inharmonic and strange.

 

As a certified nerd, I’m always ready to geek out!

The second tone was a half-step different from the real tone, and tracked in parallel motion: when the real note went up, the fake one did, too, and the size of the difference didn’t get smaller or larger. I right away (well, after calming down a bit) wondered whether it was related to the harmonic overtone sequence, with some peculiar acoustic physics going on inside my inner ear… but in order to find an overtone half a scale-step away from the fundamental, you actually have to climb way the heck up the overtone sequence to the tippity-top. And then it’s not really a half-step away anymore, is it? It would be a half-step plus a bunch of octaves. But this was not a high tone, it was literally right next to the original note on the scale. Which makes me think it was some sort of neurological artifact, and not reflecting any actual physics.

However, there was another phenomenon that was definitely related to physics.

I was tuning my guitar, using an electronic tuner, as I often do (this one a phone app; I love the 21st century). But I was having some trouble because, apparently, the tuner just wasn’t working. But only on the low E string. Worked fine on the high E, the B, the G, the D, the A — But low E wasn’t working at all; because as I could see, the needle indicating “in tune” was perfectly centered. But the note I was hearing was absolutely obviously not E.

What a strange way for an app to go wrong, I thought. Oh, well, just use the good old-fashioned method, put yer finger on the 5th fret of the E string, match it to the open A.

But they already matched.

But this is not possible. If the A on the fifth fret of the E string matches the A of the open A string, then the E string is correctly tuned.

But the open E did NOT sound like an E. It sounded, when I checked, like a B…

An acoustic guitar string is rich in all sorts of complex overtones. So, of course the B would be in there; it’s the second one you’ll find in the overtone sequence (http://www.bsharp.org/physics/guitar). A perfect fifth.

Which is when I realized that I’d lost the ability to hear the low E note itself, and was only hearing the overtones above it. The lowest and loudest of which was the B.

That is, I had become (temporarily) deaf to that frequency.

A actually went to an online tone-generator (http://www.szynalski.com/tone-generator/) and had it generate tones. The low E (around 165hz  correction: Guitar low E is E2 at 82hz), really was gone. Being only a sine wave, with no overtones, gone was gone: no sound. But as I moved the slider up, the sound faded back in.

This was actually a particularly scary moment. There was a small range of frequencies, including that low E, which no longer existed for me.

TEMPORARILY. This I kept telling myself, and so it turned out to be. I hear that low E fine now.

But at that time: I hit that E string and heard a B. Over and over and over.

For a musician, this is a level of weirdness equal to, say, stepping out of your front door and finding that your front steps don’t actually exist, but instead are a clever trompe l’oile image painted on the pavement; or that somehow you are now in Mexico City, when you weren’t before. The world just does not work that way.

Anyway, as I said: all is well now. Can’t say that enough.

<sigh>

Damn, now I’ve got myself all fidgety.

Oh, look, another fuzzy animal picture from my walk, here to cheer me up!

Yo. Public park, here, pal. You are specifically forbidden to eat me.


5 Responses to “Promoted from the comment stream, because I am a nerd and there’s a strong chance you might be, too.”

  • Mick Kelly Says:

    How odd to loose your low frequencies. As I age (I’m 66 now) I am loosing my higher frequencies. As your low E has reappeared it must be (as you say) neurological.

    Glad you are better now.

  • A Says:

    Wow. I’m glad that you’ve got it back now, but that is certainly one helluva thing.

  • Victoria McManus Says:

    FREAKY. But really interesting, all the same.

  • eub Says:

    Wow. Thank you.

    If you’re done now, that’s totally fine, but if you would care for any more —

    The doubling a consistent semitone up is remarkable. Just thinking out loud, the ear hears in “critical bands” that are about three semitones wide, so +1.5 upwards includes the +1, meaning those would normally show some masking or other interaction. It’s like masking got turned on its head. Heck, I dunno.

    And how would that possibly the in with the loss of 165 Hz… Hm, that 165 Hz E3’s partials go E3, E4, B4, E5, and so on. Were you hearing the B4, or was it in some way the B3? And come to think of it, dropping only the E3 fundamental frequency would presumably leave the E4 octave, but that wasn’t what you got. If E4 330 Hz were also lost then the B4 would come out, but you said the E4 string sounded fine. It is a strange thing.

    • Rosemary Says:

      Actually, I think the doubled note was a half-tone down, not up. And it was so weird that I’m pretty sure it happening by my auditory nerve freaking out, and not in the perfectly logical physics of my cochlea.

      As for the lost E: I just double-checked guitar tuning facts, and guess what? Low E on the guitar is E2, not E3. ( E2 A2 D3 G3 B3 E4 — Guitar music is notated an octave above the actual notes played; otherwise, there would be too many ledger lines.) However when I tested myself against the tone-generator, I actually was testing the E3, at 165hz, not the E2 at around 82hz.

      You know what that means? I lost both of those notes! The fundamental and the octave overtone. Which totally explains why I was hearing the B.

      … But not why it was a B2, and not a B3…

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