String Theory

[Tonart]

You know, the great thing about this community is that people are respectful and open. Which means that as long as you’re sincere and respectful in your posts and threads, people react kindly and positively.

It is in this spirit that I want to share some long accumulated thoughts about tone. It is going to be a long laborious article, as the subject nature is hard to truncate without losing information and meaning.

So please forgive the length of it. Here goes.

A Long Muse on Electric Guitar Tone

Part 1: The Transferability of Tone
A speaker cone can sound exactly like anything on earth and beyond, if vibrated to the right characteristic frequency - for example the human vocal cord. That happens whenever you watch a modern movie.

Speaker cone and vocal cords. Two totally different objects of totally different material and shape, yet sounding the same. It shows the shape and form of the air disturber does not matter so much as the manner in which the air is disturbed.

Just for communicative illustration, I would almost hazard to say a whale’s body can sound like Adele, if vibrated at the right freqeucy.

I lamely call this the ‘transferability of tone’.

Now if tone is transferable, can a steel string when played and heard acoustically, sound like wood when its vibration is influenced by the wood neck/body on which it sits?

Part 2: Wood and the Steel String

Why do some electric guitars sound woody and charming when played unplugged, and yet others sound metallic and thin?

The diagram above illustrates my thesis of how this ‘woody phenomenon’ happens.

The neck, and to a lesser extent the body of the guitar, are essentially vibrating on a microscale, invisible to the naked eye, due to excitement from the string energy. The frequency of the neck vibration, would tend towards wood natural frequency.

What is wood natural frequency? Tap a wood blank, and you would get a close semblance I suppose. Those luthiers aren’t crazy afterall...

So back to the diagram. The metal string is vibrating relative to its fixed ends, at pure metal string frequency. That gives a pure metal sound when the string in turn vibrates the air around it, which reaches our ears.

Here’s the bomb. The fixed ends of the string, being the nut/fret/bridge, are also vibrating due to the neck and body. So the string is really moving internally and externally. We get intra-string vibration (metal sound) and exo-string vibration (woody sound), in a sort of composite vibration.

The thesis made from the previous chapter is that a metal string can sound like a wood blank, if vibrated at wood blank frequency.

Which is exactly what is happening here. The string itself is vibrating in a spooky part-metal part-wood manner.

NB: there could be an argument that it is the body of the guitar itself that is vibrating the air directly, or echoing/coloring the sound, and that is the source of the acoustic woody sound. Perhaps. Who knows unless an elaborate experiment is funded and done. The premise of this thesis however, is that a solid block of wood can not achieve that to a level audible or significant to the human ear. It is the string itself that is doing that.

Part 3: Implications for the Electric Guitar

Everything covered so far deals with the acoustic sound of an electric guitar. Who cares how an electric guitar sounds like acoustically, right? The acoustic character of a guitar is irrelevant whenever magnetic pickups are in play.

Yet, that is the very premise that would be turned on its head here. It is precisely because pickups are magnetic, that all this becomes relevant.

Because it is the string itself that is vibrating ‘like wood’, it is detected by the pickups. According to this thesis, a woody sounding guitar would sound woody regardless of whether it is unplugged or plugged. In fact I would expect any tonal nuances and differences to be more apparent when it’s amplified!

The conclusion is that the guitar itself could matter when it comes to electric guitar tone. It could matter a lot.

Part 4: (wild) Predictions

- Bolt-on and set neck joints will give the most organic tone to a guitar. Neck-thru’s the least.

That’s because the ‘looser’ the neck joint, the more relative movement would theoretically occur between neck and bridge. This increases exo-string vibration.

- Sustain would be the reverse.

Exo-string vibration basically suck energy from the string. The more movement in a neck and body, the less a string will sustain.

- The same can be said for soft and stiff neck woods.

A perfectly stiff and hard neck wood would sustain to the maximum extent, but would be very ‘metallic and thin’ sounding. No charming woody 59 LP tone there.

- A good guitar is one that balances sustain and organic tone.

End.

Again, I have to emphasise this is just an unsubstantiated thesis borne out of intuition and inference. A lot of scientific theories start out as intuition. They become accepted and proven science after being tested out and verified in experiments. There is sadly no way I am ever going to test this out in a lab.

It could be right, it is infinitely more likely to be wrong. Because there is only one right and infinite wrongs.

I just hope this will serve as an interesting read for this forum. I’ll be happy if it can achieve just that purpose.

My one message: an electric guitar may not be just it’s pickups. It could be a lot lot more!

 

[shimmilou]

I have always been in that same school of thought (if I understood you correctly), that nearly all of the materials used on an electric guitar do affect the sound produced, and it isn't just the pups and strings (wood type/quality, construction method, nut material, finish, etc). With strings muted, knock on the body with knuckles and you can hear that sound from the amp. So in addition to the pups picking up string vibrations, the pups can pickup other vibrations, just like a microphone.

I made a short video which shows that the pups even pickup the trem-springs vibrations. It is at the end of the sloppy playing

https://www.youtube.com/edit?o=U&video_id=pG-98OfBI7I

 

[László]

I like your thinking, Tonart, and have a few ideas of my own. It’s clear from nearly a half century of playing experience that the wood, construction method, hardware and even how the pickups are mounted affect tone.

Unscientific, anecdotal, sure. But I’ve played a crap ton of guitars since 1967...

Like you, I’ve thought about why. So I’ll throw a couple more factors into the mix to ponder:

1. Pickups are microphonic. They not only act as magnetic pickups, they also pick up a little of what a microphone would “hear,” and it matters to the outcome of the sound. Microphones have their own sonic characteristics.

2. As a synthesist of long experience, I often think the guitar is analogous to a subtractive synthesizer.

The string is more or less acting as a sine wave oscillator. This oscillator is then acted upon by the materials of the guitar that filter its oscillations - both as lowpass and highpass filters - and that these filters, in addition, have characteristics of resonant filters, subtracting and emphasizing certain frequencies and causing various-order harmonics.

Instead of being done purely electronically as in a synth, the subtractive synthesis of a guitar is ultimately electromechanical.

So it’s my thinking that, for whatever reason, the filtering/resonances inherent in various neck configurations, woods, hardware types, pickup mounting methods (for example, springs, direct mounts as with P-90s, plastic pickguard mounts, etc.), all operate differently enough on the vibrating oscillator (the string) to affect the tone.

Throw in the microphonic characteristics of the pickups along with their purely magnetic operation, and you have the tones we hear from electric guitars.

Thus the material choices and design differences not only have their own characteristics in how they vibrate, they have their own characteristics in how they filter the oscillating string.

 

[toothace]

You know, the great thing about this community is that people are respectful and open. Which means that as long as you’re sincere and respectful in your posts and threads, people react kindly and positively.

It is in this spirit that I want to share some long accumulated thoughts about tone. It is going to be a long laborious article, as the subject nature is hard to truncate without losing information and meaning.

So please forgive the length of it. Here goes.

A Long Muse on Electric Guitar Tone

Part 1: The Transferability of Tone
A speaker cone can sound exactly like anything on earth and beyond, if vibrated to the right characteristic frequency - for example the human vocal cord. That happens whenever you watch a modern movie.

Speaker cone and vocal cords. Two totally different objects of totally different material and shape, yet sounding the same. It shows the shape and form of the air disturber does not matter so much as the manner in which the air is disturbed.

Just for communicative illustration, I would almost hazard to say a whale’s body can sound like Adele, if vibrated at the right freqeucy.

I lamely call this the ‘transferability of tone’.

Now if tone is transferable, can a steel string when played and heard acoustically, sound like wood when its vibration is influenced by the wood neck/body on which it sits?

Part 2: Wood and the Steel String

Why do some electric guitars sound woody and charming when played unplugged, and yet others sound metallic and thin?

The diagram above illustrates my thesis of how this ‘woody phenomenon’ happens.

The neck, and to a lesser extent the body of the guitar, are essentially vibrating on a microscale, invisible to the naked eye, due to excitement from the string energy. The frequency of the neck vibration, would tend towards wood natural frequency.

What is wood natural frequency? Tap a wood black, and you would get a close semblance I suppose.

So back to the diagram. The metal string is vibrating relative to its fixed ends, at pure metal string frequency. That gives a pure metal sound when the string in turn vibrates the air around it, which reaches our ears.

Here’s the bomb. The fixed ends of the string, being the nut/fret/bridge, are also vibrating due to the neck and body. So the string is really moving internally and externally. We get intra-string vibration (metal sound) and exo-string vibration (woody sound), in a sort of composite vibration.

From the previous chapter, the thesis made here is that a metal string can sound like a wood blank, if vibrated at wood blank frequency.

Which is exactly what is happening here. The string itself is vibrating in a spooky part-metal part-wood manner.

NB: there is an argument that it could be the body of the guitar that is vibrating or reflecting the air directly, and that is the source of the acoustic woody sound. Perhaps. Who knows unless an elaborate experiment is funded and done. The premise of this thesis however, is that a solid block of wood can not achieve that to a level audible or significant to the human ear. It is the string itself that is doing that.

Part 3: Implications for the Electric Guitar

Everything covered so far deals with the acoustic sound of an electric guitar. Who cares how an electric guitar sounds like acoustically, right? The acoustic character of a guitar is irrelevant whenever magnetic pickups are in play.

Yet, that is the very premise that would be turned on its head here. It is precisely because pickups are magnetic, that all this becomes relevant.

Because it is the string itself that is vibrating ‘like wood’, it is detected by the pickups. According to this thesis, a woody sounding guitar would sound woody regardless of whether it is unplugged or plugged. In fact I would expect any tonal nuances and differences to be more apparent when it’s amplified!

The conclusion is that the guitar itself could matter when it comes to electric guitar tone. It could matter a lot.

Part 4: (wild) Predictions

- Bolt-on and set neck joints will give the most organic tone to a guitar. Neck-thru’s the least.

That’s because the ‘looser’ the neck joint, the more relative movement would theoretically occur between neck and bridge. This increases exo-string vibration.

- Sustain would be the reverse.

Exo-string vibration basically suck energy from the string. The more movement in a neck and body, the less a string will sustain.

- The same can be said for soft and stiff neck woods.

A perfectly stiff and hard neck wood would sustain to the maximum extent, but would be very ‘metallic and thin’ sounding. No charming woody 59 LP tone there.

- A good guitar is one that balances sustain and organic tone.

End.

Again, I have to emphasise this is just an unsubstantiated thesis borne out of intuition and inference. A lot of scientific theories start out as intuition. They become accepted and proven science after being tested out and verified in experiments. There is sadly no way I am ever going to test this out in a lab.

It could be right, it is infinitely more likely to be wrong. Because there is only one right and infinite wrongs.

I just hope will serve as an interesting read for this forum. I’ll be happy if it can achieve just that purpose.

My one message: an electric guitar may not be just it’s pickups. It could be a lot lot more!

Nice Tonart! Let's add a little to the equation...the natural vibrating frequency of all objects and how that can interact resonantly(google the collapse of the Tacoma Narrows Bridge for a history lesson)

 

[Tonart]

With strings muted, knock on the body with knuckles and you can here that sound from the amp. So in addition to the pups picking up string vibrations, the pups can pickup other vibrations, just like a microphone.

1. Pickups are microphonic. They not only act as magnetic pickups, they also pick up a little of what a microphone would “hear,” and it matters to the outcome of the sound. Microphones have their own sonic characteristics.

You guys are spot on with this! Thanks for adding this important point. I’m guessing that the body vibrates the pickup, which results in relative movement (on a micro scale) between the magnets and the coil. That means relative movement between the magnetic field and the coil. ‘Self induction’, so to speak.

That could be how feedback happens, in its exact sense. And it may also explain the knuckle rap phenomenon, or the ‘speaking into the pickups’ phenomenon.

Which means that ‘self induction’ from body vibrations during plugged-in play, could plausibly color tone in a ‘woody’ manner! Again, just a guess.

I still can’t get over how some guitars sound so woody unplugged though. My eyes and ears are laser-focused on that phenomenon. I suspect there is really something special and significant happening there.

 

[Tonart]

Nice Tonart! Let's add a little to the equation...the natural vibrating frequency of all objects and how that can interact resonantly(google the collapse of the Tacoma Narrows Bridge for a history lesson)

Another good point again! I suppose certain woods, bridges and body shape combination could have a combined combined natural frequency that is closer to string frequency than others. In which case - you get better sustain!

 

[Tonart]

It’s clear from nearly a half century of playing experience that the wood, construction method, hardware and even how the pickups are mounted affect tone.

You can’t beat experience and curiosity.

 

[shimmilou]

An interesting read, along these same lines, checkout Taylor's new "V bracing" on accoustic guitars.

 

[László]

I love this stuff. So interesting!

 

[dogrocketp]

I also believe that as humans we will naturally be more attracted to certain resonant frequencies in every vibrating object we encounter. Hence, the "magic" guitars we find. And because we are not static beings (well, most of us) the favorable frequency vibrations can change over time as our perceptual systems change. This is a pseudo scientific rational for more guitars. Works for me.

 

[pac90]

Just for communicative illustration, I would almost hazard to say a whale’s body can sound like Adele, if vibrated at the right freqeucy.

I lamely call this the ‘transferability of tone’.

That Adele, she's overrated. I went to see her once, boy that was a waste of money. She did one number and left!



(copyright norm macdonald)

 

[Shizzrock]

If you ask a lot of people if they prefer vinyl or CDs a good lot of them will prefer vinyl. They will say things like "it's warmer" or "it's more natural sounding" but the truth is they like it because it is less accurate than a CD. A lot of that "woody" sound you are hearing is most likely frequencies cancelled out by the wood selection rather than an additive theory. Sustain occurs with resonance, so that is absolutely affected by the choice of every material on the guitar. If a material's resonant frequency falls in the same range as a guitars spectrum, it will add to sustain because the materials will be vibrating sympathetically and create self-oscillation to an extent. So I posit when you hear wood that is "brighter" or "warmer" you are actually hearing the opposite of the frequencies the woods cancelled out through dampening and also the additional amplitude of the frequencies the woods resonated at.

Also, the frequency is just one component of the wave. You also have the envelope, attack, decay, etc. And no sine wave is perfect, it is always complex. Every variable can affect that shape of the complex wave and therefore the perceived tonality of the guitar.

 

[Wakester]

awesome information, how many college credits is this worth, and will there be a quiz?

 

[veinbuster]

I certainly believe the composition of the guitar makes a big difference. I’ve played all of my electric guitars acoustically a fair bit and I almost always play them acoustically before I buy them.

Curiosity about the impact of the wood is my excuse for having a bunch of 59/09 guitars. Well, curiosity and I like those pickups.

And Shizzrock makes a really good point. Guitar would be pretty bloody boring if all we heard was the pure vibration of the string. Just stretch the thing over a chunk of iron and set the vibrating length with a strip of steel. I think the simplest materials experiment anyone could do would be to use a glass bottle and a tube of steel to set the string length and see how different it sounds. The fretted note would be different again.

 

[merciful-evans]

This is the most interesting topic I've come across so far. I've read everything, but need to re-read. I'll try to add something pertinent later.

 

[Tonart]

awesome information, how many college credits is this worth, and will there be a quiz?

I don’t know about the rest who made great points, but my post is worth 1 comic con point.

 

[bodia]

This thread made my head explode! I usually just judge by widdly, widdly....ker-RRRRAAAAAANNNNNGGGGGG....chugga chugga!

 

[Andrew Paul]

This is a great thread!

 

[László]

This thread made my head explode! I usually just judge by widdly, widdly....ker-RRRRAAAAAANNNNNGGGGGG....chugga chugga!

I’ll bet you say that to all the guitars.

 

[Screamingdaisy]

I've always gone by the assumption that everything affects everything else.

People can try to explain why they think that the acoustic sound of an electric guitar is inconsequential all they want, and I'll continue to disregard everything they're telling me because they're wrong.

I don't need a double blind test to prove that the sky is blue. I don't need a scientific study to confirm what I can clearly see for myself.