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Gibson Les Paul Pickups - To Cover or Not To Cover

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  • #16
    Originally posted by freefrog View Post
    To illlustrate a bit my previous answer, I share below a pic translating the electrically measured effect of a cover on a given Gibson type humbucker. The difference is clearer than in other tests on such a linear chart with vertical increments of 0.5dB (and it's not even about a "bad" cover, too thick or containing too much copper)...

    Click image for larger version

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    One problem that my friend luthier has noticed with such parts years ago was sourcing, exactly like with magnets: some sellers appear(ed) to provide parts from random / variable / "dubious" origins albeit cosmetically similar at first glance (unless they are/were themselves victims of their own suppliers).

    Now, a lucky player could certainly deal with dozens of pickups covers in his musical life without ever encoutering a "bad" one... Or without detecting the difference because of "secondary" parameters masking it. Hence my advice about personal experience as the only way to decide, IMHO and IME.:-)
    So what am I looking at exactly? What's going on at 7000Hz/17dB compared to 20000Hz/8dB?

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    • #17
      Originally posted by Securb View Post

      If you need a computer to analyze the frequencies do you think the average ear will be able to hear a significant difference?
      The reason these sort of tests are done is so the doubters don't say 'oh well thats just you wanting it to make (or not) a difference by hearing what you want to hear' - surely you're aware of the purpose of science after all.

      You can do side by side aural comparisons too (like the Bareknuckle Pickups one), and they also confirm a noticeable difference side-by-side even with the better quality covers.

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      • #18
        The Just-Noticeable-Difference for a human is around 1db (varies by pitch...) assuming "normal" hearing. So on that curve, there is probably no difference perceived out until 4k or so.

        There is a big difference in the slugs at the end vs others. But those three are pretty close. Probably indistinguishable.

        And those pitches out at 18k+ could be killed by a cable, a speaker cone, or whatever.
        Originally posted by Bad City
        He's got the crowd on his side and the blue jean lights in his eyes...

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        • #19
          Originally posted by Lucius Paisley View Post

          So what am I looking at exactly? What's going on at 7000Hz/17dB compared to 20000Hz/8dB?
          Any magnetic guitar pickup is moslty a LRC resonant filter. You are seeing the "resonant peaks" (resonant frequencies) of each coil (both being normally in series), with or without cover.

          Resonant peaks shape the upper harmonic response of such transducer. 40 years ago, people like Larry DiMarzio explained that resonant frequencies set the "voice" of pickups. That's why Seymour has mentioned resonant frequencies in his specs during decades.

          There's thousands of similar pics in my archives, thousands or comparable tests done by other people elsewhere on the web. The only difference is that lab routine here doesn't use an "integrator" circuit.

          Here is the kind of link that I use to share after such posts: http://www.buildyourguitar.com/resources/lemme/

          The Just-Noticeable-Difference for a human is around 1db (varies by pitch...) assuming "normal" hearing. So on that curve, there is probably no difference perceived out until 4k or so.

          There is a big difference in the slugs at the end vs others. But those three are pretty close. Probably indistinguishable.

          And those pitches out at 18k+ could be killed by a cable, a speaker cone, or whatever.
          This test has purposedly been done to focus on upper harmonics but yes, covers affect mainly high harmonics... and perceived "compression" on fundamental frequencies as suggested by my former precision about the impulse response screen. :-)

          The maximal difference in the Rz measurement is of a bit more than 1dB for screws and 1.5dB to 4dB from Rz to 20khz for slugs... and as previously explained, it's not even due to a bad cover.

          These differences in upper register will be heard or not according to the amount of gain used, amp and its cab(s) etc.

          I mean that if the guitar is plugged in a Jazz Chorus or Fender Twin with bright switch enabled, the difference will be much more obvious than through a Metal Zone with gain full up. :-D

          More later if time permits.


          NOTE - I live in Europe. It's 7:10 AM here. My previous answer has been posted around 2AM, while I couldn't sleep and wanted to change my mind by sharing free info with this forum (reasons : 2 people in my family are seriously hill and I wait results to know if I've been contaminated myself)...

          These private infos are meant to put in perspective my contributions in this thread (if not their "tone": I hope it's not the case since I always try to stay polite and zen in my posts). It also states why I might stay silent for a while - or definitively, who knows? "LOL".

          Duncan user since the 80's...

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          • #20
            NOTE - I live in Europe. It's 7:10 AM here. My previous answer has been posted around 2AM, while I couldn't sleep and wanted to change my mind by sharing free info with this forum (reasons : 2 people in my family are seriously hill and I wait results to know if I've been contaminated myself)...

            These private infos are meant to put in perspective my contributions in this thread (if not their "tone": I hope it's not the case since I always try to stay polite and zen in my posts). It also states why I might stay silent for a while - or definitively, who knows? "LOL".[/QUOTE]

            You're doing pretty with so much on your plate. F' this virus.

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            • #21
              So sorry to hear about your family illness. Hope they all get feeling top notch soon and that you have avoided getting the virus.
              Originally Posted by IanBallard
              Rule of thumb... the more pot you have, the better your tone.

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