"Matched"/"Balanced" Pickups

[rbkxiiowe]

This is my first post here, so hi all!

My question is - what is your understanding of what "matched" pickups means? I understand having a matched set of single coils might mean having one rw/rp, that's fine, and I read about people saying there pickups are nicely balanced in terms of output/tone, etc, which I can also understand. And a common setup would be a single coil in the neck and mid and a hotter humbucker in the bridge for grunt. But why??

Is this something one can work out on paper?

i.e. 'if I put a hot humbucker 22kOhm in the neck and a vintage single coil from an old Hofner with a weak magnet and only 3k in the bridge it should sound like this .....'

What are other peoples experiences of pickup combos in terms of ohms, magnet strength/material, tone?

[newey]

rbx-

Since this is your first post, "Welcome", even though you've been a member for a while.

Two identical pickups will have differing outputs depending upon their respective placement along the length of the string. Because a magnetic pickup generates a signal via the string vibrating through the magnetic field generated by the pickup magnets, a pickup will sound weaker closer to the bridge, where the string "travel" is less.

So, with two identical pickups, one at the neck and the other by the bridge, the neck pickup will tend to overpower the bridge pickup when the two are played in combination.

A "matched set" of pickups therefore has a bridge pickup with a bit more output to make up for this, the idea being that, when placed accordingly in the guitar, the relative output of the two should be close to each other, so that you hear both pickups equally when in combination.

The difference in output for the bridge pickup is not great. If you check out a matched set of Strat pickups, you might find, say, 5.5KΩ for the neck, and 5.9KΩ for the bridge, with the middle pup in between other two values.

Now, the above is a simpified layman's explanation, and one of our resident electronics mavens may be along to tell me I've oversimplified this topic. You should understand that a pickup's resistance in ohms is just a crude measure of its output, there are several other variables involved. Two pickups with the same resistance may have different outputs depending on magnets, construction, and other factors.

In your example, the hot HB at the bridge combined with a weak SC at the neck would represent a fairly extreme mismatch. IOW, when both were "on", you'd likely only really hear the bridge pup, the sound of the neck SC would be "swamped". As noted above, a matched set would have a bridge pup slightly "hotter" than the neck, but not by a factor of seven as in your example.

I know of no way to work this out on paper, there are a lot of variables involved. A formula of sorts has been discussed hereabouts, but it's not a real world calculation.

Of course, people's wants (or needs . . .) vary, and there's nothing inherently wrong with mismatched pickups. Some players don't use pups in combo much and may not care a whit about the differing outputs. And individual volume controls can be used to adjust the relative output of two mismatched pickups, although this is not an optimal "switch-on-the-fly" strategy for stage work.

EDIT: BTW, having a RW/RP middle pickup is not an essential feature of a "matched set" of Strat pickups, although most such sets are sold that way. The RWRP middle is for hum cancelling in combo with one of the other 2 pups. This is a relatively recent change to the traditional Strat design ("relatively recent" meaning "within my memory").

[andy]

Ditto that above! So technically, a matched set is in fact carefully mis-matched set, so as to sound matched!

I would add from my own experience that the output difference between the bridge pickup and the others can be a little more pronounced as the string moves that much less in its magnetic field, and produces less low frequencies- I have a three pickup SG with pickups of equal impedance, but the bridge unit has a ceramic magnet (usually thought to be a bit 'louder', amongst other things). Even so, the pickup has to be set higher than the other to really match in volume.

[D2o]

Jul 5, 2008 14:57:55 GMT -5 andy said:

I have a three pickup SG with pickups of equal impedance, but the bridge unit has a ceramic magnet (usually thought to be a bit 'louder', amongst other things). Even so, the pickup has to be set higher than the other to really match in volume.

Another way to think of it is to set the pickup heights so that they are all about the same distance from the strings when fretted fairly high up the fretboard. Sort of like this:



This serves two purposes:

First, since there is less string vibration at the bridge then there is at the neck, if the bridge pickup is closer to the strings it can pick up more of the (relatively less) string vibration (i.e. the same reason Newey mentioned for why bridge pickups are usually a little higher impedence).

Second, it still allows room for the greater string vibration that occurs above pickups that are farther away from the bridge, so the strings don't touch the pickup - no matter where they are fretted - and so those pickups don't pick up as much of the (relatively greater) string vibration.

Oh, and welcome to GN2, RB-IOU

[dugg]

I've found that, with strats you can set the middle and bridge pickups closer to the strings than the neck one without causing pitch change. The neck pickup is the one that is most sensitive to 'stratitis' particularly towards the low E string. Also, using a hybrid string set with a heavier lower three helps some.

[ChrisK]

This is all good info.

Keep in mind that the resistance of a pickup coil is really only completely indicative of the resistance of that coil. If all other things are equal, the pickup with the greater number of turns will have a higher output than one with fewer. It will also have a lower frequency response due to the increased inductance.

In order for the resistance alone to be meaningful as a comparison, the same type of pickup (magnets/material/strength/frequency_response, wire gauge/diameter, structure (single coil, P-90, side-by-side humbucker, stacked humbucker), manufacturer, and position along the strings) must be used.


Otherwise, it's only indicative of the resistance of that coil.


Unfortunately, and this is my major gripe about the pickup industry, there is a profound lack of data available for any given pickup. The only common data type (which actually includes meaningful things like absolute numbers), when actually published, is the resistance of the pickup and rarely for both coils in a humbucker.

To properly model and hence predict the response of an individual pickup alone and in conjunction with others, full engineering specifications must be used. This includes not only the structure (wire gauge, number of turns, physical dimensions) of the coil(s), the structure of the pickup form/frame, but also the full specificity of the magnetic material.

The reason that this stuff isn't available is because it's IP (Intellectual Property). After all, pickup makers are all only just winding wire around magnets/structures.

This IP, or trade secrets if kept so, are the only differentiation that they have.

Well, aside from commercial fraud marketing, that is.


I can publish plots from pSpice models for (proto)typical circuits, but one needs th have a working knowledge of electrical engineering and AC circuit theory and analysis to begin to "see" what this actually means.

Guitar Electronics Modeling - pSpice

[simes]

Hello.

I haven't been around for a while, but I thought here was a good place to start again.

I'm on the verge of ordering some GFS Lil' Killer SC-sized rails HB's. They sell "matched sets" of 15K (bridge), 10K (middle) and 6K (neck). This seems like an excessive difference to me, and I am thinking of getting 3 x 10K and staggering them height-wise.

Any thoughts on this?

Cheers,

simes

[sumgai]

simes,

Hey, welcome back! ;D

As Chris just said, the stated DC resistance is not very indicative of anything we can use when comparing how a pickup will sound. It could well be that what they've done, in the manufacture of that set, is to use different wire sizes, and/or different bobbins, and/or different magnet structures, and/or differnt magnet materials, yadda yadda, you get the picture by now.

As noted by many members here, Guitar Fetish seems to be putting out a pretty good product for the money, and also seems to be building a reputation for keeping the customer happy. I'd say, don't worry about the printed specifications, and order what GFS considers to be a properly assembled set of pickups. If you don't like them (and if you don't damage them somehow), then you can return them. Read the appropriate Returns Policy section on their Info page for more on this. Very friendly of them, compared to others, or so it seems to me........




BTW, just to further muddy the waters about pickups.........

It's practically a dead horse, it's been beaten so much here , but there's also the fact that, ultimately, one's tone will also depend on what kind of guitar you put the pickups into, meaning the body wood, the hardware, hardtail versus vibrato, the finish, all those myriad details that make players/owners go 'round in circles until they're stark raving bonkers, trying to find the "best" tone. Then we get to the strings, the cabling, the amp and speakers........

Makes a guy feel like he's being tortureduntil he's ready for the loony bin ! Maybe he'll even go bonkers, and start.........



Happy kibble hunting! ;D



sumgai

[rbkxiiowe]

Wow! Thanks for all that. I understand that resistance of a coil is only partly, or maybe even not any indicator of the inductance of an ...erm... inductor due to all the things mentioned above, but I assume in the case of guitars pickups it does give a pretty close idea.

ChrisK - I share your opinion on the lack of tech spec on pickups, I'd never thought it was because of the whole IP thing. I do remember having an Evans pickup that I was trying to find info on and their website gave loads of technical details. I just checked their site again and they give resistance, peak resonance and signal to noise ratio data. I think I remember they used to give Henrys as well.

I suppose you could make your own scale of magnet strength by hanging pennies off them.

Cheers.

[ChrisK]

Presuming that resistance is indicative of something such as the amount of wire, we could look at some ratios.

15K
10K
6K

Hmmm, 15K to 10K is 1.5:1 and 10k to 6 K is 1.67:1.

We might presume that the 1.5:1 ratio when squared is 2.25:1 and the 1.67:1 ratio when squared is 2.77:1. This might be indicative of inductance (or not).

Since the resonant frequency varies with SQR(LC), the original ratios before squaring might be indicative of the shift in frequency response between the pickups (these are about 1/2 octave each), and might even be indicative of the general output levels (maybe).

With all that being presumed, these ratios don't seem way out of line. I always thought the Fender ratios were too close.

And remember, the wire turns don't cause "Stratitus", the effective magnet strength does.


It's not just the IP, it's also the dearth of folk that could understand such specs and generate palatable melodies.

I actually have a fair amount of magnet data, but it is of little use without significant translations.

To measure magnetic field strength, one uses linear Hall effect sensor devices. I know how to do this as well, but the audience is limited.


Yet another permutation of Smoot's law.

"There are two kinds of people in technology;
Those that understand it, but don't manage it, and
Those that manage it, but don't understand it."

[simes]

Chris,

I didn't understand any of that, mate. ;D

Are you saying that (assuming the three pickups use similar magnets) a 15-10-6K set would give a well-balanced output when taking into consideration differences in string movement from one position to the next? Couldn't the same thing be achieved by having three identical pickups and varying their heights?

The reason I ask is that while GFS proposes 15-10-6K for its Lil' Killers matched set, several other sets like its Vintage '59 Alnico HB's (8.5/8.8K-8.0/8.2K) or its '64 Stagger Vintage Grey-Bottom SC's (6.5-6.3-5.8K) are "matched" much closer. Presumably the magnets don't vary from one pickup to the next within a set, just the winding.

There seem to be two tendencies: either keep values fairly similar across the set or put in a substantial jump from middle to bridge. The latter is all very well if you only use your bridge pickup when you want a big increase in crunch, but I for one like to use both bridge and neck (separately) for lead work.

Cheers,

simes

[ChrisK]

It's not just the IP, it's also the dearth of folk that could understand such specs and generate palatable melodies.

This is what I mean when I talk about the audience for specs. What I posted doesn't convey well to those without a background in electrical engineering. As a result, pickup manufacturer's are likely correct in their marketing tact.

The ratio's of the differences between the coils resistance, generally translatable to number of turns, probably cause an increase in bandpass frequency (pickup response) of about one half of an octave as you from the bridge to middle and middle to neck.

If I look at the distance of variation in an oscillating string, I would believe that there would be a 3 fold increase from bridge to neck. Now, to be fair, the distance coupling effect may not be linear, and the in and out direction (perpendicular to the pickup/guitar body face) generates more signal strength than the side-by-side movement (which most folk "see" as the mechanism). An oscillating string follows a figure 8 pattern.

And then there's the energy transient traveling up and down the string.

Go pluck an empty clothesline, you'll see it.


Varying the height of a pickup not only varies the output level, but the tone in often a major way as well.

[sumgai]

Chris,

...........
If I look at the distance of variation in an oscillating string, I would believe that there would be a 3 fold increase from bridge to neck.

Errr, I believe that distance decreases logarithmically from the center towards the endpoint. (This too can be seen on a plucked clothesline.) Which in turn.........

Now, to be fair, the distance coupling effect may not be linear.....

"May is the operative word here, but...... The inverse squares law is in now in play - the change in distance from a magnet to a vibrational source affects a squared change in the magnetic field. Of course, this does not necessarily translate directly to a same-strength change in a coil's output - that truly depends on many factors, only one of which I've just touched upon. You have, of course, enumerated above a small subset of the great number of factors.

As for those who understand what's supposed to be said, instead of marketing hype, well, unlike Dolby Labs, the audience is snoring. There aren't ever gonna be Engineers to wake them up, sad to say.


sumgai

[ashcatlt]

I've got that set of L'il Killers.

I'm no snob by any means, but they seem to mix well enough for my tastes. I did nothing but eyeball the pickup heights. I often use it in some "Tele" configuration (N+B, various combinations of internal series/parallel on each pickup) and am always pleased. The thing actually just sounds great all around!*


*Maybe not "all around" - I would say that I get less of the phasey sound I'd expect from +M positions, but I don't recall the stock SCs gave me that either.

[ChrisK]

Errr, I believe that distance decreases logarithmically from the center towards the endpoint. (This too can be seen on a plucked clothesline.)

Can't be. There is no string movement at the saddle (the anchor point). A logarithm is a ratio (multiplication) that can't be zero in actual value (not of exponent).

The log of 0 (movement) is an invalid function.

If the string displacement is modeled as a sine wave (which it fully isn't), up to the neck pickup, which is at Pi/4, the sine function is relatively linear. This only completely applies when the string is plucked at midpoint.

When plucked at other places, there is the energy transient that travels up and down the string, somewhat affecting the degree of movement.

This is why the harmonic content of a plucked string varies as a function of where it is plucked.


Both of the following are animations generated by worksheets written in Maple, a licensed symbolic mathematics analysis suite (I DO own a license).

Since these are licensed and copyrighted, I can't disclose the underlying worksheet mathematics (but one can buy a license [$$ = to a new Deluxe Strat or so] or consult the source material).

d'Alembert's formula

From a published work on string movement.
An off-center plucked string.

source;

Partial Differential Equations

The vibrating string: d'Alembert's formula.

from a Maple worksheet by

Anton Dzhamay

Department of Mathematics

The University of Michigan


From a published work on string movement.
Here is a fundamental sine model.

Here are static higher modes.

Here is a parabolic model.

Here is an energy propagation wave model.

Here is a cubic model with higher modes.

Here is a pentic model with higher modes.

Which looks quite similar to the paper above.

source;

E. Kreyszig : Advanced Engineering Mathematics (8th Edition) John Wiley New York (1999)

from a Maple worksheet

Section 11.3-Motion of a string

by Alain Goriely,

Department of Mathematics

The University of Arizona


Remember, we are viewing these in only two dimensions (flat screen society).

[sumgai]

Chris,

Remember, we are viewing these in only two dimensions (flat screen society).

True, but I can imagine, by virtue of virtual projection, what the third dimension carries, in the way of valid data for analysis.

To assume that a vibratory medium does not, and cannot vibrate at an endpoint is failing to view the whole, one is viewing only a static-state condition within arbitrarily chosen constricting parameters. While the motion may not be visible to the naked eye, lots of methods have been developed to actually capture said motion, not just "envision it". Google can perhaps help here?

But your point was not "let's quibble", your point was based on what's usable in reality, and therefore I yield. While the linearity is definitely questionable, thanks to the log function not being Base 10, but Base e (if I recall correctly, it's been a few days....) the resultant real-world observable results will approximate linearity closely enough for my girl friend. Or your government's work, whichever you prefer.

The so-called "energy pulse" resulting from a non-mid-point excitation is something that I've not really gone into in detail. I might dig into that aspect later on, or I might not...... depends on what's for lunch. I do know that the basic concept is valid, it's the basis for the Axon pitch-to-midi conversion system being able to detect the point along the string where it was plucked. Axon calls these "picking zones", and makes use of them to trigger non-pitch related MIDI commands, etc. Interesting, to say the least.

But back on topic.........

I understand your relentless quest to relate all things to ratios, they are good in the same way as radians, to a mathematician. But somehow I get the feeling that you've stated one thing ("there's more to the story than just DC resistance"), and then almost the opposite ("the ratio of those resistances can lead one to certain conclusions"). Granted, you disclaimed anything beyond a hazy generalization, but even just making the juxtaposition in the first place, that causes me some confusion, I gotta tell ya.

Is it Miller time yet? ;D



sumgai

[rbkxiiowe]

Cheers all for the highly technical responses. I'm trying to find a cheap electrical engineering course so I can fully appreciate them!

And sumgai - Miller?? I'm sure you mean Stella time

[andy]

Jul 18, 2008 9:18:49 GMT -5 rbkxiiowe said:

And sumgai - Miller?? I'm sure you mean Stella time

What the ol' wifebeater? Blimey- but then again, I'm a traditional Englishman in that I like my beer warm and flat!

I'm sure Sumgai has a much better smiley for that...

[sumgai]

I'm a traditional Englishman in that I like my beer warm and flat!

I'm sure Sumgai has a much better smiley for that...

This would sum up the feelings of most people when they think of warm and/or flat beer:



In fact, some folks would do this to such a person:




Yes, I have others, but those should get the point across.





sumgai

[rbkxiiowe]

What the ol' wifebeater?

Nothing wrong with the old wreck the hoose juice!

But yeah, you and I both know it's not beer unless it's brown, warm and flat.

[andy]

OW!! Stop it!

[simes]

Well, I went ahead and ordered a 6-6-10K set as per e-mail advice from GFS, given that I'm looking for a classic rock sound. I'll let you know of the results.