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... in a jazz guitar forum.
Originally Posted by ruger9
;-)
Lage's dynamic was exceptional and excellent. I contribute most of it to his playing, but the guitar and amps translated that so well. I think when he played the "tele and champ" setup he was after getting drive when he picked hard, but with the collings and the deluxe reverb (kind of?) it was all clean tones with a huge dynamic range. Very inspiring.
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04-05-2022 09:04 AM
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Actually, it is. A typical pickup will put a voltage of about 25 mV across an amp’s input load from a firm pluck on one nickel or plain steel string, which is in the vicinity of 150 for a 6 string chord. But a high output p’up like the metal guys use can generate almost a full volt across the same load from a 6 string chord from modern high output strings. So the true dynamic range of a pickup’s output can vary by a factor of 5 or more for the same player. The same picking style and amplifier set to the same SPL for mezzoforte when you play your way will give you a much louder forte from a high output pickup than a low output pickup. And turning it down to tame the loudness will enable a softer pianissimo than you could possibly play with your amp turned up high enough for a usable mezzoforte from a low output pickup. Originally Posted by Jimmy Smith
Then there’s the issue of linearity. The length, insulating covering and gauge of coil wire, the size and characteristics of the magnets, the design and construction of the pickup, etc all affect linearity of output voltage vs picking force. Coil saturation and maximum fluxivity (to borrow a term usually used for magnetic tape) cause a drop-off of the rate of rise of output voltage as it heads toward maximum. This is the very definition of compression.
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Last time I saw his live pedalboard (this was before he had the Collings), he was using a JHS Morning Glory for a little drive. Originally Posted by guavajelly
And in videos I've seen of him playing the Collings+magic Amps+new material from Squint, he is not "all clean". There is definitely drive there when he hits it hard. But in those videos, he is usually using an OX, likely as an attenuator, so he can turn the amp up to point point of "responsiveness" (some people call it the "sweet spot".) But he is definitely NOT "all clean".
Just one of many:
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It's interesting. Some players report noticing the non-linear response of a pickup to the movement of the vibrating string.
But, OTOH, I've been playing amplified guitars since 1964 and this notion never crossed my mind. I never thought, "this pickup isn't tracking how I'm picking the same way as that pickup".
If I did notice some compression, limiting or expansion, I'd probably attribute it to some other part of my rig or my technique. But, it never occurred to me.
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The OP was postulating that Lage's single coils helped him have a better dynamic range. Which is false. Any pickup regardless of how much output it has, will sound softly if the touch is soft and loudly if the touch is loud, assuming a normally dialed amp for jazz. Originally Posted by ruger9
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A pickup having 5 times the output doesn't equal 5 times narrower dynamic range. What kind of circular reasoning was that? You can try to equate the incorrect definition of compression with 'less dynamics' all you want, but it's still false. I have 2 humbuckers in series on one of my jazz guitars and I can play with a normal dynamic range - pp to ff. Less top end response to pick attack from heavier winds, which you guys equate with 'dynamics' doesn't equate a narrower range of actual volume from the pickup. Or at least not realistically quantifiable for playing purposes. That's complete nonsense! Originally Posted by nevershouldhavesoldit
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Pickups don't "compress". Their response to string movement is non linear but it is an asymmetrical non linearity that has little effect on the ratio of string movement to output and just adds harmonics. Because the strings hardly interact at all within the pickup, there is no intermodulation and so no "distorted" sound, only a subtle modification of the string tone that is part of the electric sound.
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Maybe my morning coffee still hasn't kicked in yet, but I read the opposite: he claimed a wider "true" dynamic range for the higher output PU (where I read "true" as "in practice"). It does make sense to me that you could end up with a larger usable range if your input signal is stronger (in fact, scrap the "could" from this sentence!). Originally Posted by Jimmy Smith
I know too little about how electromagnetic pickups really work, but it seems reasonable to assume there's limit to their output signal so saturation could occur, and to me that does also sound like the definition of compression. No idea though if that's likely to happen before you hit other limits (like how much controlled sound you can get from your strings).
The either compress, expand, clip, or track (linearly) all hopefully monotonically ... what other options are there? Originally Posted by aquin43
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As for dynamic range, I'd imagine we'd have to consider the ratio of peak signal to the quietist useful output. So we definitely can't talk about a pickup with 5x the output having 5x the dynamic range without some knowledge of the noise floor, or at the very least the smallest usable signal (which must be considerably higher than the noise floor to be musically useful).
No doubt there are others here with a better grasp of the physics than I, but I doubt the relationship between output voltage and string energy is anything like linear. The following may or may not be true:
The output or electromotive force is proportional to the rate of change of magnetic flux. The instantaneous magnetic flux will be proportional to the inverse square distance of the string to the pickup wire. According to the wave equation, this distance will vary in time according to the square root of the energy in the string as it oscillates closer and further away (amplitude is proportional to square root of energy). The angular frequency of the wave is also proportion to the square root of the energy, which will affect the rate of change of the magnetic flux.
That's way too much calculus for this old brain, but I think it definitely demonstrates were far from a linear relationship between picking force and output voltage.Last edited by CliffR; 04-06-2022 at 01:26 PM.
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Not disagreeing with that. But some pickups ARE better than others at it. And of course it's not just the pickup: it's the pickup and amp combination. Originally Posted by Jimmy Smith
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All pickups lose high end to capacitance (it's part of how tone controls work, which is a variable resistor coupled with a capacitor). There is capacitance at the amp input jack and within the cable, both of which shift the resonance peak of the pickup. If you use pedals, there is capacitance at the input of each (AKA "tone suck," which occurs even in "true bypass" pedals).
A single coil and a humbucker will interact differently with that, as well as sounding different inherently because of the coil interaction in the humbucker. And all pickups have internal capacitance as well, which generally speaking is proportional to the number of winds on the coil. What we are describing as the pickup response to playing dynamics may just be the result of this, not "compression."
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On this subject of "compression". I know pickups themselves don't compress. So, logic dictates that it's the AMP compressing, which would mean that the signal going into the amp got stronger, which can cause the amp to compress.
The thing I have never figured out is this: different pickups feel different, regardless of output/strength. Alnico-pole pickups (like in a strat or tele), seem to always have more punch (less compression) than a Gibson-style humbucker (bar magnet). I don't know why, but PAFs always feel "pillowy" to me, even low wind ones. The FEEL while playing them is softer.
And this isn't due to pickup strength: I have hot single coils and they do not feel like this... or perhaps, feel alot LESS like this than a normal-wind PAF does. Maybe it's not technically compression, but the feel is different... I have assumed it has something to do with the pole magnets vs bar magnet (PAF), but IDK. I also have extensive experience with Filtertrons, which are VERY LOW-wind humbuckers... and they fall somewhere in-between: less punchy/more pillowy than single coils, but still more punchy/less pillowy than PAFs. So it's not just a straight "winds/strength/output" thing...
Most punchy --> least punchy/more pillowy:
Strat - Tele - Filtertron - PAF
7.1K 8.5K 6.2K 9.0K
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I'd rather be quoted that the guitar and pickups translates his excellent dynamic range and control into very dynamic sounds through the amp and PA. The player and his ability comes first. Originally Posted by Jimmy Smith
I heard the tones to be all clean but they were not sterile – so the amp may have added a little "hair" when he dug in. In my perception his tone was cleaner tha in the Squint video.
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I like the Julian Lage crunchy sound in the video, makes me think to John Scofield in some ways.
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I (and many others) respectfuly disagree. Simply put, compression is any reduction in the amount of change in an output parameter compared to the amount of change in an input parameter. It occurs in every single system in which energy is transfered or transduced, because no system is 100% efficient. If you hit your strings with twice the physical force, you do not get twice the electrical output from the pickup for many reasons. If you could keep increasing your volume by picking harder, you wouldn't need a volume pot. Originally Posted by ruger9
The dynamics of voltage generation from perturbing a magnetic field around a coil of wire are complex and interactive. Wire gauge and/or number of windings will not tell you much about electron flow dynamics or about sound. From Pete Biltoft: "A standard strat size neck position single coil pickup is often wound with 7,500 turns of 42 gauge wire with a resulting DC resistance of approximately 5.5 k-Ohm. From this DC resistance we can calculate that the length of the coil windings on this pickup is approximately 3,657 feet [almost 7/10ths of a mile!]. Winding an identical strat style pickup bobbin with 7,500 turns of 43 AWG wire would result in a DC resistance of approximately 7 k-Ohms. This DC resistance reading is 27% higher than the reading for the strat pickup wound with 42 gauge wire and yet the true output of these two pickups as measured in volts would be very similar." This does not mean that they would sound very similar or that the relationship between picking force and output voltage is the same in both.
The capacitance of a pickup is determined by several factors including the physical separation of the coils from other materials that can carry or hold a charge, the conductivity of whatever's between the coil and other chargeable surfaces, the shape and construction of the assembly, etc. Capacitance exerts a frequency-dependent force against the flow of current through it, so it can "hold up" passage of frequencies above the cutoff that's determined by its value. There's a backward voltage ("back EMF" - look up Lenz's Law) that opposes the forward flow of current induced in a conductor. The tiny magnetic poles at the surface flip polarity spontaneously, which is more of a factor in speaker voice coils than pickups but is a characteristic of Alnico magnets that affects response time and phase consistency of induced alternating current.
The exact relationship between picking and output is different for each string and pickup design / build. It's never perfectly linear and it's never 100% efficient. More importantly, the losses increase with the force exerted and the voltage generated. So the relationship between picking force and output voltage is closer to linear when playing pianissimo. Energy losses increase as energy levels rise. But at extremely low playing levels, the signal may be so close to the noise floor of the pickup itself and/or the rest of the system that the signal is either grossly altered or lost entirely in the noise.
There are many reasons for a guitar pickup's output to increase by less of an energy increment than was applied to the strings (which is how compression affects the guitar's output signal). Magnet type, design and location affect this. Almost everything about the coils from wire gauge and coating to wire composition to separation of the coil from the magnetic structure to winding form (e.g. random vs structured) affects this. The baseplate under a Tele bridge changes the shape and location of the magnetic field around the strings compared to a Strat bridge pickup without a plate.
Many custom pickup makers seem to agree. Here are just a few examples:
- Start with Klein's pickup descriptions for an example of a high end maker who believes that compression is a fundamental component of pickup sound. He goes to great lengths to shape it, as described in his website and literature.
- From the Duncan forum, "It depends on what the pickups was designed for? Some high output pickups are dark and compressed in order to create a fat sound and to not fall apart at high volumes. The motivation for a lot of these pickups was non master-volume Marshall Plexi's that were loud and bright. Pickups designed for one purpose may not translate well in another."
- From Lollar: "Compared to other large single-coils, our Charlie Christian pickups sound warmer, with wider dynamic range and more touch sensitivity. They have very little compression and a flat EQ response."
- From Tonerider: "Like some original 1954 and 1955 Strat pickups, the Surfari set from Tonerider pickups are made with Alnico III magnets – offering nice sustain and a bright, warm, compressed attack."
- From Mark Foley: "although the tone starts with your hands the pickups will set the tone you have before you get to the amp. Capacitance is never given with pickup data but it is critical, capacitance is what gives you the dynamic, open, airy tone."
Last edited by nevershouldhavesoldit; 04-06-2022 at 04:20 PM.
- Start with Klein's pickup descriptions for an example of a high end maker who believes that compression is a fundamental component of pickup sound. He goes to great lengths to shape it, as described in his website and literature.
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All of the phenomena you describe are linear and affect only the frequency response. In particular, the adjustment of the magnets to variations in the field happens effectively instantaneously compared to the frequencies present in a guitar string. Compression would occur if the ratio of output voltage to string displacement reduced noticeably for large excursions of the string compared with very small ones. This does not happen. Originally Posted by nevershouldhavesoldit
For some actual data, refer to Fig.5.8.3 in https://www.gitec-forum-eng.de/wp-co...distortion.pdf. Here measurements of a strat pickup have been made and an empirical formula for its transfer function derived.
Pickup makers seem not to be equipped to make such measurements and rely instead on intuition as they construct yet another minor variation on one of a few old themes. Perhaps they evaluate their pickups using high gain on a tube amp and confuse the compression of an overdriven amp with pickup compression. Perhaps they are using the word to mean something else.
Of course, the string itself compresses if only because it will strike the upper frets if struck hard.
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With all due respect, I don't agree with any of this. I could not load the page you linked, so I don't know what's there. I'd be delighted to learn whatever you have to offer, if I could access it. Originally Posted by aquin43
First of all, the phenomena to which I refer are not all linear. For example, back EMF is neither constant nor linearly related to signal strength. In fact, it is zero when the string is first struck - so the coil starts to put out the full driving voltage as the tone begins. But as the string vibrates, the back emf grows and opposes the signal. This then reduces both the voltage across the coil and the amount of current it delivers. So the initial attack will be unopposed. But before it can reach its peak, it will start to be attenuated. Even 1 dB at the pickup would be quite noticeable at the speaker, as it would be amplified by the gain of the amplifier. This could certainly cause some true compression by limiting peak voltagw of the signal. As pickups may generate more or less back emf, depending on their design, some pickups will display more attenuation of peak voltage on the attack than others. It doesn't take much to achieve audibility.
The effect of capacitance on frequency-spcific signal passage is also not linear. A pure, simple first order low pass filter (which is what a simple capacitor is) has a transfer function and a phase effect like this:
Couple that nonlinearity with the other factors in an RC filter (e.g. inductance, resistance and capacitance in the wiring, inductance in the load etc) and you have a complex function that's definitely not linear. Those phase shifts can combine with the signal to remove an audible part of the spectrum and cause volume drops. This is also compression.
It's clear that we disagree, and I'd love to see the data and analyses on which you base your conclusions. I think it's quite fair to say that many authorities in the field of pickup design and construction feel as I do. Your lack of confidence in them ("Pickup makers seem not to be equipped to make such measurements and rely instead on intuition") seems a bit harsh without data to support it. And if you read the references I quoted, you'll find that none of them is referring to amplifier characteristics.
Let's try to learn more and report back.
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For a change of pace, the Beatles used flatwounds on their Gibson flattops. The single coil pickup sounds great in that context.
Gabor Szabo did magic with pretty much the same setup.
I offer these comments up to balance out the focus on arcane technical aspects of the musical product and to give a nod to artists who can make good, people pleasing sounds based on ear instead of theory. Both are important.
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Interesting reading, thank you. Originally Posted by nevershouldhavesoldit
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In Julian Lage's own words:
He talks about the pickups (and how they built the guitar around these) starting at @0:35 and elaborating more about how it can "handle" information in different registers and helping with his "orchestral" approach starting @3:20 – how the instrument is able to handle his blend of melodic lines and comping.
I know it's an advertising ;-) But he elaborately tells what he wanted from the instrument and how they achieved that. An instrument that is able to translate his dynamic playing style.
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Linearity... maybe it's time to invent the optic guitar - an optical device would probably be our best chance to get an accurate reading of string vibration? Of course it'd be a digital signal signalling crossings so it'll take some post-processing to shape those 0s and 1s into a faithful representation of playing dynamics
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The link works here. It is a .pdf rather than a web page. It is part of a very comprehensive book by professor Zollner. Gitec - Everything about the book “Physics of the Electric Guitar" Originally Posted by nevershouldhavesoldit
With all due respect, I don't agree with any of this. I could not load the page you linked, so I don't know what's there. I'd be delighted to learn whatever you have to offer, if I could access it.
First of all, the phenomena to which I refer are not all linear. For example, back EMF is neither constant nor linearly related to signal strength. In fact, it is zero when the string is first struck - so the coil starts to put out the full driving voltage as the tone begins. But as the string vibrates, the back emf grows and opposes the signal. This then reduces both the voltage across the coil and the amount of current it delivers. So the initial attack will be unopposed. But before it can reach its peak, it will start to be attenuated. Even 1 dB at the pickup would be quite noticeable at the speaker, as it would be amplified by the gain of the amplifier. This could certainly cause some true compression by limiting peak voltagw of the signal. As pickups may generate more or less back emf, depending on their design, some pickups will display more attenuation of peak voltage on the attack than others. It doesn't take much to achieve audibility.
The effect of capacitance on frequency-spcific signal passage is also not linear. A pure, simple first order low pass filter (which is what a simple capacitor is) has a transfer function and a phase effect like this:
Couple that nonlinearity with the other factors in an RC filter (e.g. inductance, resistance and capacitance in the wiring, inductance in the load etc) and you have a complex function that's definitely not linear. Those phase shifts can combine with the signal to remove an audible part of the spectrum and cause volume drops. This is also compression.
It's clear that we disagree, and I'd love to see the data and analyses on which you base your conclusions. I think it's quite fair to say that many authorities in the field of pickup design and construction feel as I do. Your lack of confidence in them ("Pickup makers seem not to be equipped to make such measurements and rely instead on intuition") seems a bit harsh without data to support it. And if you read the references I quoted, you'll find that none of them is referring to amplifier characteristics.
Let's try to learn more and report back.
With all respect, I do object.
All of the phenomena that you enumerate are in fact linear. The back emf in the coil is incidental and is what gives it its inductance. The fundamental effect is the induction of a voltage in the coil by the varying flux from the string which has been magnetised by the pickup magnets and now moves relative to the coil. The magnetic field from the string propagates at the speed of light so the total time delay across a 1 inch tall pickup will be 83 picoseconds (83 millionth millionths of a second). This means that all the interactions within the pickup are effectively synchronous. A previous point you made about the enormous length of wire in the coil even though the coil itself is small is interesting. In fact, the coil is a form of transmission line, shorted at one end and with distributed capacitance between turns. A rigorous analysis of it would be virtually impossible but fortunately, in the audio frequency range it behaves like an inductor with a capacitor across it.
There is a non-linearity in the response of the pickup because the magnetic field falls off as distance from the pickup increases. This, combined with the way the magnetisation pattern with in the string reaches the coil makes the sensitivity fall off roughly in proportion to the distance from a line slightly below the pole tips. It turns out that this form of non-linearity adds harmonics but doesn't compress the fundamental.
Note that I am using "compress" in its engineering sense i.e. amplitude non-linearity where the output no longer increases in proportion to the input.
The signal generated in the coil is subject to filtering by the inductance and capacitance of the pickup and subject to other frequency dependent losses due to eddy currents in the metalwork and cover. This filtering is what gives the pickup much of its characteristic sound and is what is manipulated by makers as they produce yet another variant of the old designs by altering the number of turns and wire gauge. The filtering, while by its nature frequency dependent, is another linear process.
Pickup making seems to be more of a craft than a scientific or engineering pursuit. Bill Lawrence was not ashamed to say in his patent for the sidewinder pickup "for reasons not known, this particular pickup construction works fantastically well."
Many of the claims made by makers about the frequency responses of their pickups, particularly about the amount of mid range, are simply not possible if they refer to the pickup in isolation.
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A Closer Look at Optical Pickups - Premier Guitar Originally Posted by RJVB
Linearity... maybe it's time to invent the optic guitar - an optical device would probably be our best chance to get an accurate reading of string vibration? Of course it'd be a digital signal signalling crossings so it'll take some post-processing to shape those 0s and 1s into a faithful representation of playing dynamics
=)
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Wait, linear process vs. linear transfer function, are we really talking about the same thing here - how the output tracks your intended ppp-fff playing dynamics? Originally Posted by aquin43
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I knew someone would have beaten me to it Originally Posted by JohanAbrandt
(reminds me of physics classes in highschool ... almost every answer I thought to be an impossibly silly wise-ass turned out to be correct
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