Pickups - could "microphonic" be a GOOD characteristic?

[Stratman76]

I've been researching again...

This started as a quest to determine how much body and neck wood type (et al) affected solidbody guitar tone.

If electromagnetic pickups are designed to "read" metal string vibration within their magnetic field, I wondered if there was anything guitar neck and body material could impart on string vibration that would translate into a tone/aurel color element. Per my father-in-law, who is a retired physics teacher and wrote a book on acoustics in musical instruments, the answer is "very little." Please note, this is not to say anything about the duration of the string vibration. Bridge, nut, pup distance to string, body wood, neck wood (and more) all contribute to dampen string vibration.

But...

While everything counts, I know that wood can especially make a difference in solidbody guitar tone. How? And how much?

I think this lies in the microphonic aspect of a guitars' pickups. In other words, the more microphonic a pickup is, the more wood vibration tone it will receive and thereby deliver as part of the signal. Hey, I know all about high-gain squeal and have avoided more microphonic pickups. What do you think about this? And then what about wax potting pickups?

[RectoGriz]

Lollar says he likes a little in his.

[big mike]

Yes. It can and is a good thing for me, especially on a tele.

[Steven_K]

I think the Fralins in my strat are slightly microphonic, especially the bridge. It sequels with too much gain gain. But they sound freekin' awesome with slightly broken up distortion - all these rich higher overtones.

[brad347]

I like microphonic pickups and I like microphonic tubes. If I can use them in my application without squeal or adverse effects, then it's not too microphonic for me.

But with regards to the original question, the impact of a guitar's body woods is bigger than your father-in-law thinks. It has more to do with how the body and neck interact with the string at the points of contact. Play a fully hollow L-5CES through a cranked marshall and you'll see what I'm talking about. It sounds and behaves very differently from a Les Paul with the same pickups. That is an extreme case, one being hollow and one being solid, but it is a testament to the fact that there is more than just the electromagnetic induction at work.

[MartinC]

I've been researching again...

This started as a quest to determine how much body and neck wood type (et al) affected solidbody guitar tone.

If electromagnetic pickups are designed to "read" metal string vibration within their magnetic field, I wondered if there was anything guitar neck and body material could impart on string vibration that would translate into a tone/aurel color element. Per my father-in-law, who is a retired physics teacher and wrote a book on acoustics in musical instruments, the answer is "very little." Please note, this is not to say anything about the duration of the string vibration. Bridge, nut, pup distance to string, body wood, neck wood (and more) all contribute to dampen string vibration.

But...

While everything counts, I know that wood can especially make a difference in solidbody guitar tone. How? And how much?

I think this lies in the microphonic aspect of a guitars' pickups. In other words, the more microphonic a pickup is, the more wood vibration tone it will receive and thereby deliver as part of the signal. Hey, I know all about high-gain squeal and have avoided more microphonic pickups. What do you think about this? And then what about wax potting pickups?

Very interesting question ... about which I know nothing, but I'm keen to read what others have to say. I did read another thread on here a while back in a similar vein in which somebody claimed that wood would impact upon tone because different woods (or other materials) would dampen a range of frequencies in different ways ... I could believe that, but I don't think any evidence was available in that thread.

:munch

[Stratman76]

I like microphonic pickups and I like microphonic tubes. If I can use them in my application without squeal or adverse effects, then it's not too microphonic for me.

But with regards to the original question, the impact of a guitar's body woods is bigger than your father-in-law thinks. It has more to do with how the body and neck interact with the string at the points of contact. Play a fully hollow L-5CES through a cranked marshall and you'll see what I'm talking about. It sounds and behaves very differently from a Les Paul with the same pickups. That is an extreme case, one being hollow and one being solid, but it is a testament to the fact that there is more than just the electromagnetic induction at work.

Interesting... But I would still say your hollow body is more resonant and therefore generates MORE (louder) wood tone to be received by the microphonic aspect of an electromagnetic pickup.

Strats would be a good test base for this because it's so easy to replace pickguards which contain pickups, caps, pots and most of the wiring.

[bluesmeanie]

Neil Young claims that an integral part of his sound is due to a microphonic pickup in that beatup old Les Paul that he plays, you know the one.

[trisonic]

I've got a Tele you can talk into - if you've a mind to that is.........
Sounds great (when used normally).

Best, Pete.

PS Did I tell you I detest "potted" pick ups?

[84Bravo]

Roy Buchanan's famous "Nancy" had a famously microphonic back pickup that can be heard squealing on the Live Stock album. If that guitar doesn't define, tone, I don't know what does.

[brad347]

Interesting... But I would still say your hollow body is more resonant and therefore generates MORE (louder) wood tone to be received by the microphonic aspect of an electromagnetic pickup.

Strats would be a good test base for this because it's so easy to replace pickguards which contain pickups, caps, pots and most of the wiring.

Take a pickup and pot it in epoxy and it will have no microphony. It will still behave differently and sound differently in an L5 versus a Les Paul.

My point is not even as much one of tone but one of resonant feedback.

The resonant, hollow body of the L5 will cause an abundance of resonant feedback as the body's vibrations sustain the vibration of the strings. So much so that at high volumes and high distortion levels, it will be very hard to control. This is the most exaggerated example I can think of of a vibrating string's sound being "informed" by the wood to which it is attached.

On a smaller scale, the same thing happens with a more resonant solid body versus a stiffer solid body (say, plywood or baseball bat ash). The construction, material, and even shape of the body and neck can all affect the way the string vibrates.

If a body has a certain resonant frequency 'fingerprint,' then the instrument will contain formants (http://en.wikipedia.org/wiki/Formant) at the wood's resonant frequencies, as those frequencies will be reinforced by constructive interference when they appear as partial frequencies of the notes sounded on the strings.

Likewise, the formants resulting from the body's resonant frequency 'fingerprint' can destructively interfere with frequencies that are close, but not identical-- mitigating those frequencies' prominence in the instrument's overall tonal signature.

Different solidbody guitars will sound differently when played unplugged. You are not hearing a ton of the body's vibration unless your ear is directly on the body--maybe a little. Most of what you are hearing is vibration directly off the strings. The main differences you hear acoustically are likely a result of the manner in which the body affects the strings.

Plug it in, and I do believe that microphony of pickups can come into play somewhat in the overall output signal, especially if they are hard-mounted to the body (like a dog-ear P90) as opposed to suspension-mounted like a Strat pickup or Gibson humbucker.

But I contend that a pickup need not be microphonic in order for body wood of a guitar to have a very real impact on the guitar's plugged-in sound.

[mccreadyisgod]

Take a pickup and pot it in epoxy and it will have no microphony. It will still behave differently and sound differently in an L5 versus a Les Paul.


:agree


Microphony can be helpful, so long as it's controlled and in a useful frequency range. Some pickups develop microphony in one specific frequency, and that's when they start to squeal and feedback like a mic shoved into a monitor.

When I read the subject of the thread, but before I read the actual substance of the posts, I was thinking of Thurston Moore and his annoyingly microphonic pickups that he does some awesome noise effects with. I actually sold a friend of mine a really terribly microphonic Epiphone pickup a few years ago so he could use it almost like a microphone. I don't think he's actually done anything with it yet... he does sing into a guitar that has microphonic pickups, though. And I've seen lots of other musicians do the same.

[brad347]

Something else to chew on: There is no such thing as the "right" amount of microphony.

There are pickups in some of my guitars that sound awesome for a lot of what I use them for, but would be unusable to a high-gain high-volume metal player.

As to the poster above, the squeal "at a specific frequency" results from microphonic feedback, much like sticking a microphone in front of a speaker to which it is connected through an amplifier.

If the pickup is functioning as a crude microphone, the main variable is "how sensitive is that unintentional microphone." The frequency of the feedback squeal, as far as I know is most likely primarily determined by external variables like distance, resonant frequencies of speakers, amp, guitar, room, etc. But I suppose a pickup itself could have a resonant frequency that contributes.

Also for the record, pickups and tubes are not the only things in your guitar rig that can be microphonic. Anything that can cause some sort of variable electrical response in proportion to mechanical movement/vibration can exhibit microphonic behavior. In rare cases I've even heard of intermittent/bad solder joints exhibiting crude microphonic behavior. Capacitors can certainly be microphonic. In fact, a condenser microphone IS nothing more than a capacitor that is specifically designed to be as microphonic as possible (hence the name-- "condenser" is the old-school term for "capacitor," and you will often hear them referred to as "capacitor microphones.")

[HHB]

my 58 LPjr says YES!

[ugacrow]

If you really want to get the "ahhhhhs" to sound right when playing a cover of Octupus' Garden, then you'd better have microphonic pickups so you can sing into 'em!

[dazco]

Anyone who thinks wood has little effect on tone, well, they just don't even have the slightest clue. Start building guitars and trading parts etc. It shouldn't take much time before you realize what a ignorant statement that is. Do it for years and by then you'll laugh at such statements and shake your head. at that point you'll have a dead solid understanding of not only to what degree body wood affects tone, but same with every part right down to bridges and pots etc etc etc. And if you don't believe how much body wood matters, heres one that will shock the he|| out of you.....probably the biggest percentage of the overall voice of a given guitar is imparted by the neck. yeah, go ahead and flame away, but unless you've done your homework don't discount anything you have no proof for just because it doesn't sound logical to you.

[brad347]

Anyone who thinks wood has little effect on tone, well, they just don't even have the slightest clue. Start building guitars and trading parts etc. It shouldn't take much time before you realize what a ignorant statement that is. Do it for years and by then you'll laugh at such statements and shake your head. at that point you'll have a dead solid understanding of not only to what degree body wood affects tone, but same with every part right down to bridges and pots etc etc etc. And if you don't believe how much body wood matters, heres one that will shock the he|| out of you.....probably the biggest percentage of the overall voice of a given guitar is imparted by the neck. yeah, go ahead and flame away, but unless you've done your homework don't discount anything you have no proof for just because it doesn't sound logical to you.

I might not have phrased it exactly that way, but I pretty much agree with every single thing in this post.

[treeofpain]

My original 52 tele has a bridge pu that is slightly microphonic. Not bad enough to squeal at normal playing volumes, but it does liven up th sound. Absolutely the best sounding tele I've ever played, period.

[DANOCASTER]

Microphonic - GOOD

Heavy Potting - BAD

OVERLY Microphonic - Not so Good

[brad347]

potting pickups didn't really become popular until much later. In fact I think a lot of what many people hear as "vintage" sound in pickups is a small to moderate amount of microphony.

Old Fender pickups, many old PAFs, etc. were a bit microphonic. Old DeArmonds on the early gretsches, and the old Guild humbucker, were so microphonic that you could literally talk into them and be heard loud and clear.

[brad347]

Microphonic - GOOD

Heavy Potting - BAD

OVERLY Microphonic - Not so Good

Agreed! :)

[stormin1155]

My only experience with microphonic pickups is that they don't sound good. I had an old Gibson ES225 that had a P90 going dead... it was microphonic.... sounded terrible. I've also had some cheap imports with crappy sounding, microphonic pickups.

Most good quality pickups are not very microphonic at all, and the notion that they "hear" difference between different woods, particularly in an environment of amplified sound, seems pretty far-fetched to me. Think about it... How loud is the acoustic sound coming off a solid body guitar? 60db maybe? How loud is the sound coming off a cranked amp? 120db? So what is the pickup more likely to "hear" even if it is microphonic?

So if my logic holds, the effect of wood, construction, hardware, whatever really has to be how it effects the vibration of the string, not any ambient sound the pickups "hears".

[brad347]

My only experience with microphonic pickups is that they don't sound good. I had an old Gibson ES225 that had a P90 going dead... it was microphonic.... sounded terrible. I've also had some cheap imports with crappy sounding, microphonic pickups.

Most good quality pickups are not very microphonic at all, and the notion that they "hear" difference between different woods, particularly in an environment of amplified sound, seems pretty far-fetched to me. Think about it... How loud is the acoustic sound coming off a solid body guitar? 60db maybe? How loud is the sound coming off a cranked amp? 120db? So what is the pickup more likely to "hear" even if it is microphonic?

So if my logic holds, the effect of wood, construction, hardware, whatever really has to be how it effects the vibration of the string, not any ambient sound the pickups "hears".

Well, one broken pickup and a few inexpensive pickups are not, in my opinion, a good sample for making an objective judgement about the tonal consequences of microphony in pickups. :)

I disagree with the notion that "good quality pickups" are not microphonic. Microphonic pickups in my opinion include some with reputations for being the best ever made, including original PAFs, original P90s (working ;)), early Stratocaster and Telecaster pickups, and old DeArmond pickups. Etc.

Regarding whether or not a microphonic pickup could "hear" vibrations coming off the body-- I understand your skepticism. However, your analysis of the situation overlooks one important point.

Try this experiment: Play your guitar through your amp at a reasonable volume, but put your ear directly on the guitar body as you play, and press your head down to the body as tightly as you can. NOW which do you hear more? The amp sound or the sound directly off of the body?

In the case of something like a dog-ear P90, the pickup is screwed directly to the body of the guitar, allowing for maximum transfer of energy. The pickup is directly coupled to the vibrating body!

I believe you might be able to concede that, in cases such as that, if a pickup were microphonic enough, it might indeed transduce energy from the vibrating body.

[splatt]

Anyone who thinks wood has little effect on tone, well, they just don't even have the slightest clue. Start building guitars and trading parts etc. It shouldn't take much time before you realize what a ignorant statement that is. Do it for years and by then you'll laugh at such statements and shake your head. at that point you'll have a dead solid understanding of not only to what degree body wood affects tone, but same with every part right down to bridges and pots etc etc etc. And if you don't believe how much body wood matters, heres one that will shock the he|| out of you.....probably the biggest percentage of the overall voice of a given guitar is imparted by the neck. yeah, go ahead and flame away, but unless you've done your homework don't discount anything you have no proof for just because it doesn't sound logical to you.
yup;
ditto.
dt / spltrcl

[gkoelling]

I've got a Tele you can talk into - if you've a mind to that is.........
Sounds great (when used normally).

Best, Pete.

PS Did I tell you I detest "potted" pick ups?

Actually, you can talk into any Tele but I know what you mean, most are like talking to a brick wall. I have one you can talk into, too. My voice comes through the amp quite nicely and, yes, potted pickups suck.

[splatt]

fwiw,
i do tend to like certain pickups
when they aren't fully or heavily potted or
potted at all,
pickups that have at least a bit of microphony present.

dt / spltrcl

[mccreadyisgod]

It may be worth noting that, as pickups age, they naturally become more microphonic than they were when brand new. Components age, there's years of micro-vibrations, and just corrosion and sweat and humidity and everything else a guitar is subjected to over 30, 40, 50 years...

And these are the pickups that many players value the most. Without getting into minutiae, most players would rather have a 1958 PAF than a 2008 PAF; ditto strat pups, ditto P-90's, ditto DeArmonds...

So, unless anyone has contrary information, one would assume that as pickups develop a bit of microphony, they become more desirable. Some pickups go too far... like a girl who got too slutty... but a nice little bit of controlled microphony is awesome.

[brad347]

There might be something to that. I'd buy that for a dollar.

Whether old pickups were "born" more microphonic than their modern counterparts or whether they got that way over time through environmental stress is never something I'd considered.

[Steven_K]

Most good quality pickups are not very microphonic at all, and the notion that they "hear" difference between different woods, particularly in an environment of amplified sound, seems pretty far-fetched to me. Think about it... How loud is the acoustic sound coming off a solid body guitar? 60db maybe? How loud is the sound coming off a cranked amp? 120db? So what is the pickup more likely to "hear" even if it is microphonic?
All a pickup being microphonic means is that the soundwaves from the amp are causing it to vibrate in such a way that it produces a signal from that vibration - feedback. So, as someone already pointed out, you can't compare the db level but which is going to vibrate a pickup more - the soundwaves from the amps or the vibration of the guitar? Its going to be the second.

[mccreadyisgod]

All a pickup being microphonic means is that the soundwaves from the amp are causing it to vibrate in such a way that it produces a signal from that vibration - feedback. So, as someone already pointed out, you can't compare the db level but which is going to vibrate a pickup more - the soundwaves from the amps or the vibration of the guitar? Its going to be the second.


That's completely and totally false, sorry.

A pickup that is "microphonic" is a pickup that is capable of picking up acoustical vibrations in the air, making it into a crude microphone. The term microphonic in this instance means "like a microphone".

A lot of people notice microphony in pickups when they develop that squeaky, squealy feedback from their guitar amps. When it gets an annoying, high-pitched feedback, then it's because the pickup has become badly microphonic. But the feedback is just a symptom of microphony, they are not the same thing.

[splatt]

Whether old pickups were "born" more microphonic than their modern counterparts or whether they got that way over time through environmental stress is never something I'd considered.
i've been told that
many were "born" with more microphony.
can't verify personally, but it came from a man
whom i consider to be one of the great pickup
designers/builders.
dt / spltrcl

[mccreadyisgod]

Whether old pickups were "born" more microphonic than their modern counterparts or whether they got that way over time through environmental stress is never something I'd considered.


Some pickups certainly are more microphonic from the start, and some are built in such a way that they will become more microphonic over the years. Others are manufactured in ways that makes them less microphonic, like epoxy potting. But with rare exception, pickups will develop/increase in microphony over many years as they age. Anything will shake and rattle more as it gets older... just look at Robert Plant...

[luis h]

if there where no contribution to the sound by wood, they long ago stop using plastic beside wood, is not just the looks. let me think just some more for a better answere but is like having a spring attached to the celling and a load attached to the other side, you make an initial movement and the spring statrs oscilating up and down , think that the string is the spring and the wood is the load, thers always and interaction, it thepends a lot on how heavy or light is the weight on the actual movement and 'sustain' of the movement.

is not the best analogy thats what i ask for more time for a better one, but the point is that theres an interaction of the guitar in the vibration of the strings, the guitar is vibrating at the same time and damping some frequencies, and also amplifying others.

i have a lot in mind at the same time, and lenguage diferences doesn't help, tell me if i'm clear or if i need to explain my self more.

[luis h]

Originally Posted by mccreadyisgod:

A pickup that is "microphonic" is a pickup that is capable of picking up acoustical vibrations in the air, making it into a crude microphone. The term microphonic in this instance means "like a microphone". end quote


how does the microphonic pup pick sound waves, if they are made for picking only the magnetic field of the strings???

why does the sigur ros guy use his pups as mic?

im so new to this i don't know how to quote

[zombiwoof]

Neil Young claims that an integral part of his sound is due to a microphonic pickup in that beatup old Les Paul that he plays, you know the one.

I've actually seen Neil sing through that microphonic pickup on stage, so it is definitely true!

Al

[mccreadyisgod]

how does the microphonic pup pick sound waves, if they are made for picking only the magnetic field of the strings???

why does the sigur ros guy use his pups as mic?

im so new to this i don't know how to quote


A guitar pickup becomes microphonic when some of the pieces of the pickup become just a little tiny bit loose, giving them the ability to vibrate in microscopic levels. Usually it's the pole pieces. So, when sound waves hit the pickup, it causes these parts to move and vibrate, which then goes into the electronics of the pickup.

As for why some people do this... sometimes it's because it looks cool, mostly it's because it sounds... different... you can use your guitar FX and amp to alter the sound of your voice. Mostly it's an atmospheric element in the music.

As for how to quote... if you see a post that you want to quote, there is a button in the bottom right-hand corner of every post labeled "Quote".

You'll get it eventually! :BEER

[stormin1155]

Well, one broken pickup and a few inexpensive pickups are not, in my opinion, a good sample for making an objective judgement about the tonal consequences of microphony in pickups. :)

I disagree with the notion that "good quality pickups" are not microphonic. Microphonic pickups in my opinion include some with reputations for being the best ever made, including original PAFs, original P90s (working ;)), early Stratocaster and Telecaster pickups, and old DeArmond pickups. Etc.

Regarding whether or not a microphonic pickup could "hear" vibrations coming off the body-- I understand your skepticism. However, your analysis of the situation overlooks one important point.

Try this experiment: Play your guitar through your amp at a reasonable volume, but put your ear directly on the guitar body as you play, and press your head down to the body as tightly as you can. NOW which do you hear more? The amp sound or the sound directly off of the body?

In the case of something like a dog-ear P90, the pickup is screwed directly to the body of the guitar, allowing for maximum transfer of energy. The pickup is directly coupled to the vibrating body!

I believe you might be able to concede that, in cases such as that, if a pickup were microphonic enough, it might indeed transduce energy from the vibrating body.


I agree with your last point. And I also agree that to some extent, many, if not all pickups are somewhat microphonic. If it produces a sound by tapping it (with anything other than metal), it is microphonic.

My point is that coloration of the tone by the type of wood, other materials, construction, etc. occurs primarily by their affect on how the strings vibrate, not by the ambiant sound coming of the body. And notice I said 'primarily', because I'm sure at some level there is some contribution. I believe it to be significantly less than the the contribution of the wood, etc. on how the strings vibrate.

I tried the experiment you suggested. When I held my ear next to the strings (about as close as the pickup is to the strings), even at very moderate amplification, all I could hear was the amp. Not the strings at all. Now when I pressed my ear against the body I could hear the vibrations of the body, probably not so much through my eardrums, but by the transfer of vibrations to the bone structures of my ear, because even when I put my hands over my ears I could still hear it.

Your point about the dogear P-90 pickups is interesting. So I wonder, all things being equal, which of course they seldom are, a dogear P-90 would sound differently than a soapbar P-90? Those of you who have both types, do you think they react diffently?

[84Bravo]

Theory vs applied: about twenty five years ago I rewound a T-top humbucker and put it, unpotted, in my 335. It sounded great, fabulous in the bridge. I began to have second thoughts about an unpotted pickup in a semi-hollow guitar, so I took it out and wax potted it and put it back in. The sound changed so dramatically that we were all stunned. There was also a slight increase in reading DC resistance. So, my point is simply that potted/unpotted, in my own personal experience, resulted in a different tone and a slightly different physical measurement of the coil. Whether one is better or worse depends on your ear and where and how you play.

[Walter Broes]

Hmmm...I like a microphonic pickup, which makes for an extremely "alive" guitar, in a studio setting.

On stage, I think microphonic pickups are a major PITA, though a little bit doesn't hurt.

Obviously, if you're a high gain player (I'm not), I don't think a microphonic pickup will be for you.

[daddyo]

A mildly microphonic bridge pup is fundamental to a classic Tele sound. Mine is and it's great:)

[brad347]

My point is that coloration of the tone by the type of wood, other materials, construction, etc. occurs primarily by their affect on how the strings vibrate, not by the ambiant sound coming of the body. And notice I said 'primarily', because I'm sure at some level there is some contribution. I believe it to be significantly less than the the contribution of the wood, etc. on how the strings vibrate.

I agree with this point 100%. I hope you didn't think I was trying to imply otherwise. :AOK

I tried the experiment you suggested. When I held my ear next to the strings (about as close as the pickup is to the strings), even at very moderate amplification, all I could hear was the amp. Not the strings at all. Now when I pressed my ear against the body I could hear the vibrations of the body, probably not so much through my eardrums, but by the transfer of vibrations to the bone structures of my ear, because even when I put my hands over my ears I could still hear it.

Your point about the dogear P-90 pickups is interesting. So I wonder, all things being equal, which of course they seldom are, a dogear P-90 would sound differently than a soapbar P-90? Those of you who have both types, do you think they react diffently?

Nice! That's exactly the intended result. What I was getting at was microphony through direct mechanical coupling-- i.e. "the transfer of vibrations to the bone structures of the ear." :) This type of microphony is, of course, the reason that it becomes necessary to put sensitive condenser microphones in shock/suspension mounts to prevent them from picking up noise from the floor through the mic stand.

It's interesting to consider that while some pickups are screwed directly to the body, others are in effect "suspension mounted" on springs. PAF humbuckers come to mind, as do the spring-mounted pickups on a strat pickguard.

Kinda makes you wonder what type of effect that would have, particularly with a moderately microphonic pickup. Also makes you wonder why that design was chosen in the first place. Was it purely for height adjustment, or was there some sort of isolation component in the design philosophy?

[Steven_K]

A pickup that is "microphonic" is a pickup that is capable of picking up acoustical vibrations in the air, making it into a crude microphone. The term microphonic in this instance means "like a microphone".

A lot of people notice microphony in pickups when they develop that squeaky, squealy feedback from their guitar amps. When it gets an annoying, high-pitched feedback, then it's because the pickup has become badly microphonic. But the feedback is just a symptom of microphony, they are not the same thing.
:huh That's not really any different from what I said. What is it that is causing the pickup to "hear" acoustic vibrations other than the pickup itself, or some components in it, vibrating?

[mccreadyisgod]

:huh That's not really any different from what I said. What is it that is causing the pickup to "hear" acoustic vibrations other than the pickup itself, or some components in it, vibrating?



Your post seemed to imply that the only sonic result of a microphonic pickup is feedback. You can get feedback from a guitar with no microphony, and you can get no feedback from a fairly microphonic pickup, so the two aren't necessarily synonymous. It is true that the harsh, squealing, undesirable feedback from *most* guitars is due to bad microphony.

[Stratman76]

Take a pickup and pot it in epoxy and it will have no microphony. It will still behave differently and sound differently in an L5 versus a Les Paul.

My point is not even as much one of tone but one of resonant feedback.

The resonant, hollow body of the L5 will cause an abundance of resonant feedback as the body's vibrations sustain the vibration of the strings. So much so that at high volumes and high distortion levels, it will be very hard to control. This is the most exaggerated example I can think of of a vibrating string's sound being "informed" by the wood to which it is attached.

First off, thank you for this post. I consider it nothing short of brilliant! It's easy to see how guitar body and neck wood can influence the duration of a strings' vibration. What I'm driven to learn is WHAT actually gets imparted into a given strings' vibration.

On a smaller scale, the same thing happens with a more resonant solid body versus a stiffer solid body (say, plywood or baseball bat ash). The construction, material, and even shape of the body and neck can all affect the way the string vibrates.

If a body has a certain resonant frequency 'fingerprint,' then the instrument will contain formants (http://en.wikipedia.org/wiki/Formant) at the wood's resonant frequencies, as those frequencies will be reinforced by constructive interference when they appear as partial frequencies of the notes sounded on the strings.

So this is...adding/imparting harmonic overtones to a strings' vibrational...pattern? So, on a tone affecting level, this is altering what is presented to the pickups' magnetic field-reading ability of the strings' vibration? Or is the addition of a "partial frequency" being overstated and/or misinterpreted?

I now feel like Uncle Billy in 'It's a Wonderful Life.'
"I can't think anymore...it hurts!":huh

[Steven_K]

Your post seemed to imply that the only sonic result of a microphonic pickup is feedback. You can get feedback from a guitar with no microphony, and you can get no feedback from a fairly microphonic pickup, so the two aren't necessarily synonymous. It is true that the harsh, squealing, undesirable feedback from *most* guitars is due to bad microphony.
Yeah, I didn't mean that, but I can see how what I said was confusing.

[wingwalker]

I actually prefer a slightly microphonic pickup...covered buckers and tele lead coils more so than others but I like a little in them all!

[brad347]

So this is...adding/imparting harmonic overtones to a strings' vibrational...pattern? So, on a tone affecting level, this is altering what is presented to the pickups' magnetic field-reading ability of the strings' vibration? Or is the addition of a "partial frequency" being overstated and/or misinterpreted?

I now feel like Uncle Billy in 'It's a Wonderful Life.'
"I can't think anymore...it hurts!":huh

OK, re-reading my post I think I made it sound more difficult than it really is! :rotflmao

Look at it like this. Every object, for the most part, has a resonant frequency. Actually, most things have multiple resonant frequencies-- A tuning fork would only have one, but most objects will have several. Even a room will have a resonant frequency. A column of air inside a partially-full beer bottle will have a resonant frequency. Virtually anything that's not totally dead will have one or more frequencies at which the object will resonate when mechanically excited... tapped, struck, blown on, whatever.

Take a bar from a marimba. It's a piece of wood tuned and shaped to sound a specific note (frequency) above all others when it is struck with a mallet. But it will also sound many other frequencies! It will sound the overtones of the fundamental frequency to which the bar is tuned, but it will also sound several other frequencies--unrelated to the fundamental pitch--that are inherent in the wood itself. Even if the bar was shaved to tune at a different fundamental frequency, these frequencies-- the formants-- would stay mostly the same.

Formants are one thing that determines timbre of an instrument. In other words, these frequencies, which are unrelated to the pitches being played (and which remain constant), are part of what helps us tell one person's voice from another, or one guitar from another, or a saxophone from a 'cello. The other main factors in timbral discrimination are (IIRC), transient envelope (i.e. the shape of the initial attack), and the proportions of the fundamental frequency's overtones. Detailed description of that is beyond the scope of this little note, so bear with me. ;)

NOW-- a guitar body is not the same as a marimba bar in that it is not tuned to resonate at one specific frequency. But it DOES still have certain frequencies at which it is more easily excited to vibrate.

Here's where I get to the easy explanation! :rotflmao

Say a guitar body has a resonant frequency at 110 Hz. Each time 110Hz is sounded on a string, either as a fundamental frequency or as an overtone of a lower pitch, the body will become easily excited and vibrate freely at that pitch. The body, being connected to the strings, will transmit that vibration back to the strings, aiding in the sustain of that particular frequency component. Conversely, say another pitch was sounded that was close, but not identical-- let's say 100Hz. This is close to (but not exactly) 110Hz. The body would be trying to vibrate at 110 Hz, and since the wavelength is slightly shorter, it would quickly cause destructive interference and discourage the string from vibrating at that 100Hz frequency, dampening the sustain of that particular frequency component.

On a carved top hollowbody instrument, this might even cause wolf tones (http://en.wikipedia.org/wiki/Wolf_tone), a phenomenon with which anyone who's ever played a cheap violoncello is surely familiar. The effect is more exaggerated on hollow instruments, and can manifest itself in all sorts of less-than-mellifluous ways including beating and out-of-tune sounds. But though the effect is different/mitigated somewhat on a solidbody plucked instrument, the acoustical phenomena of constructive and destructive interference are still very much real. It is just a bit more subtle. On a bowed instrument, the notes are sustained for longer and the beating and interference is easier to hear.

Another thing to note is that even on inexpensive string instruments with wolf tones, the wolf tones will often "play themselves out" or disappear over time as the wood "learns" what to do. I don't want to get into the whole "vintage versus modern" debate, but that is certainly proof that SOMETHING is going on as an instrument ages/is played.

So I say all that to say, the wood of the body manifests its influence on the strings, tonally, in all sorts of ways-- some of which we understand, and, undoubtedly, some of which we probably don't.

Hope that helps clear it up. (Clear as mud, right?)

[luis h]

now thats an explanation, :bow

[Tone_Terrific]

Consider that whacking the body, with the stings damped, will create some output from the pup that sounds, sort of, like whacking the body, then consider how much less energy the string vibration puts into the body's vibration than hitting it with your fist.

How much of the mechanical (body) tone is transmitted as output vs the string's magnetic/electrical signal? Does it sound better or worse? How would you know unless you could mount the pup outside the guitar, isolated from the body vibrations but stil sensing the strings and compare? Piezo pups are pretty good at capturing body tone in acoustic guitars, but they are excessively microphonic for rock purposes in that application but work in some bridges where they capture more of the string tones.....like a lot of stuff, nothing is simple. It's a good thing we don't have to know how things work to use them.:huh

[Stratman76]

Lollar says he likes a little in his.

Jason Lollar, I believe, has wax potting down to a science.

[uOpt]

Movement inside the coils are very audible. Over at LPF somebody posted pre- and post-potting Tele neck pickup soundclips, just in case it wasn't obvious.

Movement of the pickup relative to the vibrating body is also a big factor. The kind of mount - direct to wood, humbucker ring, full-size pickguard, Tele bride - all make audible differences. The wobbly mounts like in a Strat actually bring more life to the sound because they now add movement that isn't synchronized with strings or body.