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Post by aquin43 on May 10, 2021 3:44:17 GMT -5
Could you do something like a single loop coil, and an effectively infinitely tall coil in order to define the boundaries? The best I can do is 2mm deep slices at the top and bottom of the normal 11mm tall coil space.
Normalised at 1mm. Brown is coil at top, red at bottom, orange - bottom scaled to top level at 1mm. Magnet mu 3.5.
It is only slight influence of the mu of the magnet that prevents the second curve from being merely the first one displaced by 9mm
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Post by gckelloch on May 11, 2021 18:05:30 GMT -5
"Just when I thought I was out..." So the question is: would even 20% artificial 2nd harmonic distortion be enough to create audible modulation with the 2nd sring harmonic? FI, the 2nd string harmonic is seen in the Tillman Java app as less reduced than the fundamental in any typical pickup positon. Although the app doesn't account for pickup characteristics, string distance or the guitar damping properties, I imagine the 2nd string harmonic would be considerably louder than the artificial 2nd. Still, it was interesting to go through all this.
I was also thinking that the asymetric distortion would affect all string harmonics to varying degree, so there would be some amount of an artificial 2nd harmonic added to each string harmonic, no?
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Post by antigua on May 16, 2021 20:29:50 GMT -5
"Just when I thought I was out..." So the question is: would even 20% artificial 2nd harmonic distortion be enough to create audible modulation with the 2nd sring harmonic? FI, the 2nd string harmonic is seen in the Tillman Java app as less reduced than the fundamental in any typical pickup positon. Although the app doesn't account for pickup characteristics, string distance or the guitar damping properties, I imagine the 2nd string harmonic would be considerably louder than the artificial 2nd. Still, it was interesting to go through all this. I was also thinking that the asymetric distortion would affect all string harmonics to varying degree, so there would be some amount of an artificial 2nd harmonic added to each string harmonic, no? Yeah the harmonic doubling would apply to each physical string harmonic, but it's vanishingly small above the fundamental. |
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Post by aquin43 on May 17, 2021 9:47:38 GMT -5
Think about the notes at the 12th fret on a strat with the neck pickup selected. According to the pickup placement they should have no second harmonic but the waveform coming out of the pickup will have a very large amount of second harmonic
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Post by antigua on May 17, 2021 13:37:51 GMT -5
Think about the notes at the 12th fret on a strat with the neck pickup selected. According to the pickup placement they should have no second harmonic but the waveform coming out of the pickup will have a very large amount of second harmonic
I have a spectrum analyzer on my phone, so I just plugged in a Strat real quick and confirmed fretting notes at the 12th fret with the neck pickup shows a lot of second harmonic content. The peaks bounced around a lot, but the second was similar in amplitude to the fundamental and the third harmonic. But according to this www.physics.princeton.edu//~mcdonald/examples/guitar.pdf the second harmonic from "y-axis" movement should be rather small. Where do you think a strong second harmonic comes from, in the case of a neck pickup being used with a string fretted at the 12th fret? |
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Post by aquin43 on May 17, 2021 17:28:45 GMT -5
Think about the notes at the 12th fret on a strat with the neck pickup selected. According to the pickup placement they should have no second harmonic but the waveform coming out of the pickup will have a very large amount of second harmonic
I have a spectrum analyzer on my phone, so I just plugged in a Strat real quick and confirmed fretting notes at the 12th fret with the neck pickup shows a lot of second harmonic content. The peaks bounced around a lot, but the second was similar in amplitude to the fundamental and the third harmonic. But according to this www.physics.princeton.edu//~mcdonald/examples/guitar.pdf the second harmonic from "y-axis" movement should be rather small. Where do you think a strong second harmonic comes from, in the case of a neck pickup being used with a string fretted at the 12th fret? Purely from the pickup non-linearity. In this case the string has a second harmonic nodal point over the pickup so any true string second harmonic will not register but the asymmetrical non linearity of the pickup generates plenty of second harmonic from the fundamental. Third harmonic is probably truly produced by the string. The gross non linearity of the pickup seems to undermine the simple frequency response models based on the location of the pickup and plucking point on the string as a delay line, at least in the steady state. In the transient attack phase, where the signal consists of a series of spaced impulses, I would guess that the linearity of the pickup is much less important (cf ms performing a non linear operation on an impulse like waveform). It is well known that the timbre of a note is pretty much established by its starting transient, and this seems to survive the pickup non-linearity. |
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Post by gckelloch on May 17, 2021 20:47:53 GMT -5
Update 5/19/21: Taking a cue from the ms post just below, I recorded the low E at the 12th fret through my neck Microcoil pulled at the neck pickup from both the Side and the Top at a Loud and Quiet velocity. I set the analyzer to average the result, and I hit the "Hold" button after two seconds (when the harmonics settled). drive.google.com/drive/folders/1Pw9oh6bEB5nKtjArBg-whMbpA5EsfMTm?usp=sharing The results for Top pull are not consistently much different than the Side pull, but maybe with slightly stronger upper even harmonics. The 2nd does appear to be a bit weaker in the Quiet versions. Incidentley, I also ran the Lead (bridge) Microcoil through the analyzer to see how loud the fundamental was compared to the second two harmonics on the open E, and they were generally all at the same level as each other, with the fundamental level dropping below the others when I picked close to the bridge. I would then suppose they'd all be equally louder than when though a 42AWG wire Fender SC, but I no longer have such a pickup to compare.
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Post by ms on May 18, 2021 18:21:33 GMT -5
So I did a non-linearity test with a pickup in the strat neck position, fretted on the 12th. The pickup is a strat pickup sized sidewinder with high permeability poles. I measured the relative level of the 2nd harmonic and fundamental for two kinds of rapid picking: 1. very soft, and 2. very hard. In case 1, the result was about -21 db, and in case 2 about -11 db.
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Post by pablogilberto on Jun 17, 2021 8:44:07 GMT -5
I imagine the thin copper shielding under the coil also reduces the hum harmonics in the critical hearing range and above. hi antigua and gckellochI'd like to understand the thin copper shielding under the coil better. I've seen some pickups manufacturer do that. Like this.  What is the effect and advantage? When using this, is it correct to assume that the start should always be connected to the ground? Since the start wire is near the polepiece, which is connected to the ground via the copper shielding. Will there be any problem when the start wire is connected to the hot of guitar wiring? Thanks! |
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Post by gckelloch on Jun 17, 2021 9:43:14 GMT -5
I imagine the thin copper shielding under the coil also reduces the hum harmonics in the critical hearing range and above. hi antigua and gckellochI'd like to understand the thin copper shielding under the coil better. I've seen some pickups manufacturer do that. Like this. What is the effect and advantage? When using this, is it correct to assume that the start should always be connected to the ground? Since the start wire is near the polepiece, which is connected to the ground via the copper shielding. Will there be any problem when the start wire is connected to the hot of guitar wiring? Thanks! Here's a test showing how different shielding types affect EMI. Copper works better than Aluminum when in thinner sheets. alexkenis.wordpress.com/2016/04/13/guitar-pickup-theory-7-effect-of-pickup-cover-material-on-tone-and-noise/Not sure I understand your second question. The coil will short if the start (negative) and hot (positive) leads are connected. The ground wire is from the chassis. Kdeeping it separate allows for reverse-phase wiring. |
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Post by antigua on Jun 19, 2021 1:08:35 GMT -5
I imagine the thin copper shielding under the coil also reduces the hum harmonics in the critical hearing range and above. hi antigua and gckellochI'd like to understand the thin copper shielding under the coil better. I've seen some pickups manufacturer do that. Like this. What is the effect and advantage? When using this, is it correct to assume that the start should always be connected to the ground? Since the start wire is near the polepiece, which is connected to the ground via the copper shielding. Will there be any problem when the start wire is connected to the hot of guitar wiring? Thanks! Yeah, ideally the start is hot and the finish is to ground, and the pole pieces are grounded, so that the outer layer of the coil will not be on the hot side of the circuit, and noise that is received from the pole pieces is grounded out. That will increase the capacitance a bit, but a lower noise floor is probably preferable to the reduced capacitance. The amount of noise that is gained or lost depends on the noise source. I have a Fender Mustang, which has built in phase switching, so I can compare start to ground versus finish to ground, and there is a small difference in noise levels, but usually not a very big difference. Like so many other things, people have wired pickups both way forever and nobody ever says the guitar must be broken one way or another. |
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Post by pablogilberto on Jun 24, 2021 0:58:30 GMT -5
antiguathanks for the reply! If the hot side is in the start of the coil (inner windings close to the polepiece magnet) will be there no problem since the polepiece magnet is connected to the ground via the copper shield? I'm also checking the Telecaster Bridge pickup since it is similar in such a way that the baseplate is conductive and is connected to the ground. What they usually do is connect the baseplate into the start of the coil (inner winding) which is also connected to the ground. What do you think is the reason? Thanks a lot
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Post by antigua on Jun 26, 2021 23:36:25 GMT -5
antiguathanks for the reply! If the hot side is in the start of the coil (inner windings close to the polepiece magnet) will be there no problem since the polepiece magnet is connected to the ground via the copper shield? I'm also checking the Telecaster Bridge pickup since it is similar in such a way that the baseplate is conductive and is connected to the ground. What they usually do is connect the baseplate into the start of the coil (inner winding) which is also connected to the ground. What do you think is the reason? Thanks a lot Yeah if the pole pieces as grounded, then it's OK for the start of the coil to be hot. We discussed this a few years ago in relation to grounded blades and humbucker pole pieces guitarnuts2.proboards.com/thread/8347/why-ground-rails-bladesI'm not sure if there is a rhyme or reason to the grounding scheme of a Tele bridge pickup, it could just be a happy accident, as was the case with many things Fender did in the 50's. |
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