Electromagnetic pickup and micro phonics, tone, wood, pick attack etc....

[Peteus]

Ok, I know this is usually a bad idea to ask on a guitar based forum but, a electric guitar works by a electro magnetic pickup detecting the vibration of magnetically responsive strings and inducing a current in the coils which is sent to the amp to amplify. So in scientific theory: There is no extra effect from wood types, size, dimensions (unless you count length of strings vibrating) etc...

Now, I know this is a bit of a nasty subject with most people but, from my experience there is an acoustic difference in solid body guitars and this is in some small way transfers into the sound when plugged in however, I have never done a straight test using the same strings, same bridge and pickup being swapped out. However, I'm trying to distinguish my what I though (and therefore probably believe) vs what actually happens.

Now, before everyone may get angry with me, the only way I can think that acoustics make a tonal difference in a solid body guitar is microphonics through the electro magnetic pickup. So my question is when potting pickups does it remove all microphonics or is there still a small percentage which can actually be detected and hence, wood types, pick type etc.. may have some effect on a final tonality of the guitar. Can someone explain to me if this is scientifically correct?

[Mike Sulzer]

Ok, So in scientific theory: There is no extra effect from wood types, size, dimensions (unless you count length of strings vibrating) etc...

Science says no such thing. The wood of the body and neck affect the vibration of the string, and so the sound generated by sensing this vibration with a magnetic pickup depends on the material. Obviously solid body instruments made from different materials sound very different. Making the body hollow or whatever can affect the vibration even more.

[Peteus]

Science says no such thing. The wood of the body and neck affect the vibration of the string, and so the sound generated by sensing this vibration with a magnetic pickup depends on the material. Obviously solid body instruments made from different materials sound very different. Making the body hollow or whatever can affect the vibration even more.

That seems reasonable to me. So in essence the wood variety will affect the strings vibration. Any ideas on how that happens?

Also anyone any idea of if a electromagnetic pickup has any element of microphonics which would help bring about the acoustic tone?

[Mike Sulzer]

That seems reasonable to me. So in essence the wood variety will affect the strings vibration. Any ideas on how that happens?

Also anyone any idea of if a electromagnetic pickup has any element of microphonics which would help bring about the acoustic tone?

When a string vibrates the force along the string varies; the varying pull on the bridge tends to flex the body, setting it into motion. This takes energy from the string, that is, damps it. But the amount of damping as a function of frequency is dependent on the material and how it is used. In a similar way, the neck bends with string vibration, and since it bends more than the body, its material and size should be a bigger factor than the body.

I do not think an electric guitar pickup reproduces much signal from the body. Fasten one down to the body away from the strings and see what you get.

[Mark Hammer]

Mike's spot on.

Keep in mind that a string is a mechanical device that has energy inserted into it. That energy provokes motion, but the motion doesn't last a long time. What kind of motion remains after how much time is partly determined by the physics of the body, neck, frets, bridge, tailpiece, and nut (among other things).

Consider the difference between a big jazz box and a solid-body. The jazz box will likely have a floating wooden bridge. At initial pick attack, during those first 50msec, the jazz box and solid-body probably won't sound too different. But after the initial pick attack, the "lifespan" of the various harmonic components will quickly become very different. Indeed, because of the manner in which a floating wooden bridge quickly damps harmonic content, such that the note settles down to fundamental and lower-order harmonic PDQ, that increased contrast creates the impression of hollow-body electrics having greater dynamics.

Ultimately, the pickup can only sense what the string gives it to sense, and the string can only offer what the body, bridge, nut, frets, etc. allow it to give.

[bbsailor]

That seems reasonable to me. So in essence the wood variety will affect the strings vibration. Any ideas on how that happens?

Also anyone any idea of if a electromagnetic pickup has any element of microphonics which would help bring about the acoustic tone?

Peteus,

The carved top, f-holed, big jazz box guitars players sat in the rhythm section of the band. Early unamplified recordings just allowed you to hear the initial attack of the chord strum to work very close with the drummer to accent certain beats. Later, when the pickup was added to allow the guitar to be heard better, the playing technique evolved beyond chord playing to melody playing and also working with a smaller set of other band members. These guitars typically used heavy gauge strings, .013" string for the high E, and the energy from the string pluck/strum, was quickly sucked away from the string by the body absorbing the energy, giving the classic high initial attack but little sustain. This affected how these guitars were played and sounded with other instruments.


Later in the 1950's when the solid body electric guitar was made popular by Leo Fender and others, the string energy was more preserved by less energy being sucked out of the string on by the solid body. Add the evolution of higher output pickups, extra gain in the amplifier stage, signal compression, clipping and the sound of a guitar is now more of the guitar and amplifier combination to form the whole instrument. As Mike says, the solid body guitar still imparts some effect on taking energy from the strings, but not as much as was in the big jazz box acoustic guitars. The energy that is taken from the solid body guitars is in a different spectrum and can be heard by listening to the non-amplified sound of any guitar. Since the pickups only transduce the energy in the vibrating string over the pickup they will be affected by the energy that is left in the string and is most evident when listening after the initial attack during the first second or two of the string decay. Some guitar construction techniques and materials can contribute to a noticeable extended sustain. I have a neck through body Schecter Research 25.5 inch scale length guitar that I purchased used that has the best acoustic sustain compared to my many other screw-on neck guitars.


If you want to retrieve a little more acoustic sound from your pickup, build the Tillman FET buffer in the jack of your guitar cable. This will not add any body acoustics but eliminate the 350 pf of capacitance from the guitar cable and raise the resonant frequency to capture a little more of the higher harmonics which is typically where the acoustic sound lies. Lower impedance pickups in the 25mH to 35mH winding range, like the Les Paul low impedance recording guitar will broaden the pickup response. Putting a piezo sensor near or on the bridge, buffered by a 3M to 5M input impedance can allow you to sense and/or mix a more acoustic-like sound with your electric sound. Rick Turner reported that winding low impedance pickups with Litz wire can add more high frequency components to the sound. Alumitone pickups have been reported to have a more acoustic-like quality. Only your ear (emphasize the word YOUR) is the final arbitrator in these claims to satisy what you are listening for!

Remember, the highest primary frequency of a high e string on the 24th fret is about 1312Hz and the pickup resonant peak in the 2 to 3KHz region emphasizes certain harmonics and masks the upper harmonics, where the acoustic harmonics lie, by the steep cutoff after the resonance point. This is what creates the traditional electric guitar sound vice the acoustic sound that you seek.

I hope this points you in the right direction to try the various options to achieve your goal. Keep us posted about your progress.

Joseph Rogowski

PS. Mark posted his response while I was composing the above.

[Bruce Johnson]

It's refreshing to read some sensible answers on this subject. As Peteus is referring to, on some other instrument forums there is a weird cult-like thing about hating Tonewood and Luthiers who talk about it. I'm a veteran Luthier, building mostly high-end electric basses, and I spend a little time on TalkBass. On there, as soon as you mention anything about how wood affects the sound of an electric bass, a whole crowd wells up, stamping their feet and yelling that WOOD DOESN'T MATTER and ALL ELECTRIC BASSES SOUND EXACTLY THE SAME EXCEPT FOR THE PICKUPS, or something like that. And they get really hostile about it. I've tried many times to patiently explain it to them, and I've been accused of being a liar and a Snake Oil Salesman. They don't make any sense at all, and I've given up trying. Hardly any serious Luthiers bother posting on TalkBass any more, because that anti-wood crowd has gotten so obnoxious and silly.

Anyway, Peteus, you're obviously read some of those threads and are wise enough to have recognized that something isn't right in their arguments. Believe us, the wooden frame of an electric guitar or bass plays a very important part in the final sound that you hear in the amp. The pickup plays an important part too, but it's just one portion of the instrument.

Mike's description above is right on. The mini-summary is:

1.) The string has a tonal curve of its own, based on its construction and condition. That's the original source.

2.) The frame of the guitar modifies the strings' tone by flexing minutely as the string moves back and forth. How and how much it modifies the strings' tone will depend on how stiff the frame is, and what materials the frame is made of. A really stiff frame doesn't modify the strings' tone very much, so in that case, the tone on the strings will mostly be from the strings themselves. However, the more flexible the frame is, the more it will modify the tone ringing on the strings. The movement of the wood can change the whole attack/sustain profile and the frequency curve. This stiffness and movement of the frame is the main way in which we Luthiers play around with shaping the sound of the instrument. But this only works if the frame is capable of flexing. That's where people get so confused. If you build a super rigid frame, then it really doesn't matter what you build it out of; you'll just hear the strings' own tone. But that's not what we do. We build them flexible so that we can use the wood to shape the tone.

3.) The pickup detects the tone that's on the string, which is the strings' own inherent tone that has been modified (or not) by the frame. The pickup then modifies that tone in its own way, before sending it down the cord to the amp. The pickup mostly modifies the tone the way that a Parametric Equalizer does; by pushing sections of the frequency curve up or down. But it can also change the attack curve some, with magnetic field strength and proximity to the strings.

It's important to understand the sequence above. The pickup can only detect what's left on the strings after the frame has modified it. The pickup cannot really put back what the frame has taken away, particularly in the attack/sustain curve. If a soft frame has killed the sustain, no pickup is going to put it back. If a rigid frame has left the string with long sustain, a pickup can't cut it off.

Likewise, if a rigid frame has made the strings' tone thin and piercing and metallic, then it's very difficult for a pickup to make it rich and warm. The pickup can boost the low mids and cut some highs, but it's still going to sound thin and metallic overall. And if a soft frame has made the tone deep and thumpy, a pickup can cut the lows and boost the highs somewhat, but it's still going to be deep and thumpy overall. It doesn't do much good to boost what isn't there.

The point is that frame is the coarse adjustment that makes the big changes to the sound of the instrument. The pickup fine-tunes the sound. We choose the string, build the overall sound of the instrument in the frame, and then smooth it out by building or selecting the pickup that works best with it.

This is for your secret knowledge only. Please don't paste it on one of those other forums and get yourself beaten up. Because they might follow you back here.

[David Schwab]

I'm a veteran Luthier, building mostly high-end electric basses, and I spend a little time on TalkBass. On there, as soon as you mention anything about how wood affects the sound of an electric bass, a whole crowd wells up, stamping their feet and yelling that WOOD DOESN'T MATTER and ALL ELECTRIC BASSES SOUND EXACTLY THE SAME EXCEPT FOR THE PICKUPS, or something like that.

Oh yeah, I've been through that over there too. It's pretty funny.

Another good one was a guy on YouTube that has this channel where he gives guitar lessons. I think it's groovy guitar lessons or something. Anyway, he posted a video doing a comparison of guitar pickups. But the way he did it was just play totally different guitars! He starts off by saying "we have proven that the wood the guitar is made out of doesn't matter" etc! I sent him a polite message saying that was nonsense, and besides that he's using guitars with different scale lengths and construction, etc. He proceeded to send a stream of rude ignorant messages back which was mostly based on he was rich and has X amount of custom guitars, so he know all about guitars... etc.

If any of these people tried building an instrument, or even swapping a rosewood neck for a maple neck on a Strat, they would hear that there is a tonal change.

My experience is that a lot of the tone cones from neck construction, since that is the most flexible part, unless it's a hollow body.

[jason lollar]

"Another good one was a guy on YouTube that has this channel where he gives guitar lessons. I think it's groovy guitar lessons or something. Anyway, he posted a video doing a comparison of guitar pickups. But the way he did it was just play totally different guitars! He starts off by saying "we have proven that the wood the guitar is made out of doesn't matter" etc! I sent him a polite message saying that was nonsense, and besides that he's using guitars with different scale lengths and construction, etc."
agreed nonsense- what about matching the pot values in both guitars, having strings with the same amount of hours played on them and a multitiude of other factors.
My bitch is there is another sector that thinks they can predict with high accuracy the results of using lets say an alder body with a maple fingerboard and this or that type of bridge etc..... There is huge variablity from one piece of alder to another ect.. combine all these variables and see how consistant you get with 20 teles all made of the same wood. youll hear a difference from one guitar to another from subtle to easily noticeable even with matched pots, fret wire, tuners and all related hardware including matched pickup sets.

[Mike Sulzer]

In order to investigate the different sounds resulting from different woods and how they are used, I built a guitar that looks like a solid body, but is hollow with a removable back. Inside is a 5.5" by 7" by up to 3/4" thick piece of wood mounted at the four corners. The special bridge goes through the top and rests on the slab of wood. By varying the type of wood, the thickness and its structure (braces if thin) you can get quite a variation in sound. I usually leave in a thin braced piece of spruce because the sound has some of the attributes of a semi-solid, although a bit less bass.

[Bruce Johnson]

Likewise, you can build a guitar with a solid body of one particular wood. If you start with the body real thick, with no chambering, it will sound bright, with plenty of sustain and a wide frequency range. At that point, it almost doesn't matter what wood you use; most will sound about the same.

Now start thinning that body down, and cutting chambers in the area between the neck pocket and the bridge. The thinner and weaker (more flexible) that you make the body, the tone will get warmer and richer, and you'll lose sustain and overall frequency range. This is with one single piece of wood. That one piece of wood can make a guitar really bright or really warm, all depending on how stiff or flexible you allow it to be, by how you cut it.

This is where so much of the confusion is. Someone assigns a particular tone to a particular species of wood, as if the mere presence of that species of wood causes that tone to happen. But then it's real easy to show completely contrasting examples. A rich warm guitar with a maple body, and a bright metallic guitar with a mahogany body. And the beer bottles start flying......

Different species of wood, and even different boards of the same species, will create different tones on the strings of an electric guitar, but ONLY if the structure is built to be flexible. Wood all sounds the same when it can't move.

The same things apply to necks and the woods that you build them out of. A very stiff neck won't change the tone on the strings much, so the guitar will sound mostly like the strings, bright and metallic. The softer and more flexible the neck is, the more the tone on the strings becomes warmer and richer. And you can build a really stiff mahogany neck that will be very bright, or a soft flexible maple neck that will be warm, or the opposite of either.

In comparing the overall frame, in my experience the stiffness (or flexibility) of the neck will mostly control the lower side of the frequency range. It will also set the overall sustain and clarity. The stiffness (or flexibility) of the body has more effect on the high end frequencies; how bright or warm they are. But you can play around with the balance between the stiffness of the neck and the stiffness of the body. Many combinations are possible. I generally like to build my basses with moderately stiff necks and very soft bodies. That's usually a good compromise to richen and warm the tone, but keeping reasonable sustain and clarity. On a bass, players will tend to notice warmth more when it's on the higher end. Putting a soft neck on a stiff body usually ends up unappealing sounding, particularly on a bass. That's a "Thud" bass that thumps and clicks, and has no sustain.

Guitars may want a different balance. You can warm up the bottom end by softening the neck, but keep the body stiff to make the high end crisp and icy.

Like I said, many combinations are possible. And then you can play around with pickups to smooth it out and optimize it.

[shawnl]

Another good one was a guy on YouTube that has this channel where he gives guitar lessons. I think it's groovy guitar lessons or something. Anyway, he posted a video doing a comparison of guitar pickups. But the way he did it was just play totally different guitars! He starts off by saying "we have proven that the wood the guitar is made out of doesn't matter" etc!

I can't remember the guy's name, but some acoustic playing guy tried to put out a video about making your own pickups. The video in fact illustrated nothing about the practice other than the man suggesting that you have no business making them unless you are an electronic engineer. It alarms me how unwilling some people are to dive in and investigate for themselves.

[Steve Conner]

Fascinating thread

[Mark Hammer]

To cut the naysayers some slack, though, it helps if we approach the "debate" (and I use the term loosely) from a more statistical viewpoint, and treat the tone as having multiple sources of variance, some of which account for, or predict at least, more variance or interindividual differences in tone, than other sources.

Holding pickups constant, we will undoubtedly notice variance stemming from tonewood and body design. Conversely, holding tonewood and body design constant, we will notice variance stemming from pickups used. Holding wood, design, and pickups constant, we will notice variation stemming from hardware and how the strings are terminated: nut material, fret material, bridge design and materials, tailpiece design, and so on.

In fact, ALL of the elements will, at some point and in some set of circumstances come to "matter". Where I suspect the "pickups reign supreme" sentiment comes from with bass players (or simply bass chatters) is that bass bodies and necks tend to be deliberately more "inert" than guitar bodies (though I imagine there are many lively bodies out there). Tap on them, and you don't get the same evident resonance you get from many guitar bodies. Of course, what such thinking completely neglects is that bass bodies have to be more to that end of the spectrum precisely because tonewood does matter so much. Make a bass out of "spongier" material and there would be precious little string energy for the pickups to detect.

In a sense, their reasoning is partly correct, but is seriously misled by what is staring them in the face the whole time: the need to prevent the impact of tonewood from detracting from the intended sound.

[Lyrebird Steve]

Here's some experimental research that shows Vibrational Behaviour of different types of guitars.

Dr. Russell's Research - Acoustics of Guitars



... and some experimental research on the effect of tone woods

http://www.stormriders.com/guitar/te...uitar_wood.pdf