Body wood affects tone

Gassage

Three-ColourSunburst said:

Megii said:

Thanks for responding to my posts @Three-ColourSunburst , great mate, cheers!

Sorry, but it feels like I am trying to play a tennis match with half a dozen people throwing serves at me!

I am still collecting research on this topic in the hope that I can give some more definitive answers to the points raised, including what you posted.

Cheers!

I make it 6-0, 6-0, 6-0, against you and you'll need to requalify next year.

Three-ColourSunburst

NelsonP said:

OK, but no speaker was used. I would imagine that there would be some impact from that.

i.e.
i) string vibrates
ii) pickup turns vibration into electrical oscillation
iii) amplfier / speaker reproduces this
iv) some of the energy from the speaker is transferred back to the guitar body
v) guitar body resonates at certain frequencies and returns these to the string
vi) pickup turns these new vibrations into electrical oscillation

The guitar body material may be important is stages iv/v

Just a thought.

The initial signal is created entirely by the string vibrating, this signal is then amplified which then causes the air in the room to vibrate. The harmonic content of this sound is determined by the initial picking of the string, plus the harmonics added by the amp. This sound forces the body of the guitar to vibrate. The vibration in the guitar's body is most unlikely to be true 'resonance'. Rather the body of the guitar will be forced to vibrate in sympathy with the sound in the room. Crucially, the body cannot be vibrated by the air in the room until the signal has already been generated and amplified.

It doesn't seem clear to me how the guitar body could 'break' this initial signal, especially given that the amplifier will be producing far more energy that the body of the guitar could absorb, plus  the very high impedance of the bridge / body interface on an electric guitar means that very little vibration from the body will be fed back to the strings which, let's not forget, are still been driven by the original signal and all that energy in the vibrating air in the room.

Meanwhile the player, being a bit of a shredder, already picked another 50 notes!

crunchman

Three-ColourSunburst said:

Also proposed is a modelling of the string-body coupling, which shows that only a negligible amount of energy from the vibrating string reaches the body of the instrument and that a smaller amount still returns up the string.

I know I said I wouldn't post in this thread again, but I respectfully suggest that they need to revisit their modelling.  Anyone can generate a model, but if the model doesn't match reality it's useless.  I can feel the body vibrating on my guitars when I hit a string.  That's not a negligible amount of energy.

This next bit is even worse:

Three-ColourSunburst said:

Firstly, an acoustic guitar is designed to have a very low impedance (and hence high conductance) at the bridge, this energy being transferred into a thin, light soundboard (in a top-quality instrument as light as 100g before bracing is added). The low mass and yet high stiffness of the soundboard means that the limited amount of energy available from the string can excite the board into a state of forced vibration with the minimum loss of energy, so maximising the sound output. (Even so, the energy in any body in a state of forced vibration will tend to dissipate rather quickly.)

 In comparison, an electric guitar body is specifically designed not to 'resonate' (or rather be easily excited into a state of forced vibration) being solid with a high mass and, in the interests of maximising sustain, will be fitted with a heavy bridge with very high impedance and hence very low conductance.

Apart from the fact that Impedance and Conductance are electrical terms, any bridge that will support the tension of the strings must be rigid.  It will therefore transmit almost all of the vibrations of the strings to the body.  The kind of bridge you are attempting to talk about that does not transmit vibration to the body would have to be made of something like rubber to absorb the vibration.  It wouldn't be rigid and the guitar would not stay in tune.

I knew I shouldn't have looked that this thread again, but to see such utter rubbish being spouted does make me worry that one or two people might actually take you seriously when you attempt to come up with "science" that you have no understanding of.

I suggest that you go away and do an evening class in A level Physics and stop bothering us.

Bidley

Three-ColourSunburst said:

The initial signal is created entirely by the string vibrating, this signal is then amplified which then causes the air in the room to vibrate. The harmonic content of this sound is determined by the initial picking of the string, plus the harmonics added by the amp. This sound forces the body of the guitar to vibrate. The vibration in the guitar's body is most unlikely to be true 'resonance'. Rather the body of the guitar will be forced to vibrate in sympathy with the sound in the room. Crucially, the body cannot vibrate until the signal has already been generated and amplified.

Jesus Christ.

richardhomer

I'm in Tarporley near Chester today - a bit overcast - but dry so far....

NelsonP

Three-ColourSunburst said:

NelsonP said:

OK, but no speaker was used. I would imagine that there would be some impact from that.

i.e.
i) string vibrates
ii) pickup turns vibration into electrical oscillation
iii) amplfier / speaker reproduces this
iv) some of the energy from the speaker is transferred back to the guitar body
v) guitar body resonates at certain frequencies and returns these to the string
vi) pickup turns these new vibrations into electrical oscillation

The guitar body material may be important is stages iv/v

Just a thought.

The initial signal is created entirely by the string vibrating, this signal is then amplified which then causes the air in the room to vibrate. The harmonic content of this sound is determined by the initial picking of the string, plus the harmonics added by the amp. This sound forces the body of the guitar to vibrate. The vibration in the guitar's body is most unlikely to be true 'resonance'. Rather the body of the guitar will be forced to vibrate in sympathy with the sound in the room. Crucially, the body cannot vibrate until the signal has already been generated and amplified.

It doesn't seem clear to me how the guitar body could 'break' this initial signal, especially given that the amplifier will be producing far more energy that the body of the guitar could absorb, plus  the very high impedance of the bridge / body interface on an electric guitar means that very little vibration from the body will be fed back to the strings which, let's not forget, are still been driven by the original signal and all that energy in the vibrating air in the room.

Meanwhile the player, being a bit of a shredder, already picked another 50 notes!

I'd guess the feedback loop is pretty fast - much faster than you'd think. Probably measured in milliseconds.

"Rather the body of the guitar will be forced to vibrate in sympathy with the sound in the room" - this is the very definition of resonance.

The bit about the 'very high impedance of the bridge / body interface' isn't correct, as proven when you put your ear on the body of the guitar and pluck a string.

Gassage

richardhomer said:

I'm in Tarporley near Chester today - a bit overcast - but dry so far....

Name this well known phrase or saying;

Anybody here from Canada? Anybody here from Australia?
Tarporley? Anybody here from Tarporley? Stand up, all those from Tarporley and shake hands with the person on your right.

NelsonP

richardhomer said:

I'm in Tarporley near Chester today - a bit overcast - but dry so far....

Pay attention at the back Homer, or you'll be off to see the headmaster again :-)

Megii

Three-ColourSunburst said:

Crucially, the body cannot vibrate until the signal has already been generated and amplified.

It's just not true - I know well from experience that with all my solid body guitars, the body does vibrate appreciably, even when the guitar isn't plugged in - I often practice this way, and I can both feel the body resonating, and hear an appreciable acoustic volume, even if it's not as loud as a full acoustic or semi-hollow instrument, it's definitely there. It's something I look for in what I would consider to be a good electric guitar.

Gassage

Three-ColourSunburst said:

Exactly such a rigorous academic study has been done, and it found that body wood has no effect on the tone of an electric guitar. As I posted on page 11...


OK, I have found some real academic research on this topic, overseen by a Professor of physics and acoustics. I have also found a TV clip about their research, a full text copy of their paper and also some discussion by the leading author of other research they have done into this topic, including some blind listening tests. This will do for now. It's in Portuguese, probably because any English speaking academic putting a research proposal forward to study such a topic would risk becoming the next Eric Braithwaite! Looks pretty rigorous, using a mechanical picking device to avoid the problem of human players 'unconsciously' altering their picking technique in order to get the tone they expect.

Sobre o acoplamento corda-corpo em guitarras elétricas e sua relação com o timbre do instrumento. Physicæ 9, 2010, pp. 24 - 29

'String-body coupling on electric guitars and its relation with the timbre of the instrument.'

Rodrigo Mateus Pereira(1), Albary Laibida Junior, Thiago Corrêa de Freitas.

(1) Tecnologia em Luteria, Universidade Federal do Paraná, Brazil.

I've recently read a totally contradictory Chinese Study to yours.

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Three-ColourSunburst

crunchman said:

Apart from the fact that Impedance and Conductance are electrical terms, any bridge that will support the tension of the strings must be rigid.  It will therefore transmit almost all of the vibrations of the strings to the body.  The kind of bridge you are attempting to talk about that does not transmit vibration to the body would have to be made of something like rubber to absorb the vibration.  It wouldn't be rigid and the guitar would not stay in tune.

As I said, I am not making this up of the top of my head, just reporting what I have read elsewhere. I think that, whatever the terminology used, it is perfectly true that an acoustic guitar is purposely designed to transmit as much energy as possible to the soundboard, whilst a solid-body electric is designed to minimise the transmission of energy at the body/ bridge interface, which is why it has better sustain. If, as you claim the bridge would 'therefore transmit almost all of the vibrations of the strings to the body' the guitar would have no sustain.

Here are a couple of the sources I drew on.

The body of an electric guitar is normally manufactured from solid material in such a way that the bridge is as rigid as possible. As a rule, no considerable energy is transferred from the string to the body, and therefore the string signal of a solid-body electric guitar does not decay as rapidly as the signal of an acoustic instrument. In general, the "sustain" (long decay) of the electric guitar exceeds that of the acoustic guitar.

In Figure 4 typical conductances are presented as measured at the midpoints of the nut and the bridge, respectively (the end supports of the open D and G strings) of the Explorer guitar. The lower diagram shows that the conductance at the bridge is low over the entire measured frequency range with a minor increase towards higher frequencies. This means that at the bridge termination the string "sees" a support with no considerable energy loss, despite the fact that this guitar features a vibrato mechanism.

http://www.ingentaconnect.com/content/dav/aaua/1999/00000085/00000001/art00020

See also.

https://www.researchgate.net/publication/282789912_Fleischer_H_und_Zwicker_T_Investigating_dead_spots_of_electric_guitars_Acustica_united_with_acta_acustica_85_1999_128_-135

As a rule, apart from very low frequencies, for a well-made solid-body instrument the conductance is lower at the bridge than at the neck. This holds for as well the electric bass [6] as the electric guitar [8].

http://www.ingentaconnect.com/content/dav/aaua/2005/00000091/00000002/art00007

Etc. Etc.

May I respectfully suggest that the above authors are more knowledgeable  than you, and your talk of 'rubber bridges' indicates that it is you who should 'go away and do an evening class in A level Physics'.

Cheers!

Bidley

Have you ever played a guitar?

Three-ColourSunburst

Bidley said:

 Crucially, the body cannot vibrate until the signal has already been generated and amplified.

Jesus Christ.

Thanks for picking up my sloppy writing. I obviously I meant to say

"Crucially, the body cannot be vibrated by the air in the room until the signal has already been generated and amplified."

Thanks!

Ravenous

By the way chaps, Mechanical impedance is a thing.  It's quite legitimate and nothing to do with rubber bridges.

It's a complex thing though. Just saying a high impedance prevents vibration is wrong - there will be a small amount of string energy transmitted to the body, those of us who actually play from time to time will have felt it.

Unfortunately I suspect some people here are googling for advanced engineering topics and basing their debating points on something they first heard of over the weekend.

crunchman

Three-ColourSunburst said:

May I respectfully suggest that the above authors are more knowledgeable  than you, and your talk of 'rubber bridges' indicates that it is you who should 'go away and do an evening class in A level Physics'.

I don't need to.  I'm a qualified Physics teacher.  If I ever go back to teaching, I just hope you don't turn up in one of my classes.

Gassage

crunchman said:

Three-ColourSunburst said:

May I respectfully suggest that the above authors are more knowledgeable  than you, and your talk of 'rubber bridges' indicates that it is you who should 'go away and do an evening class in A level Physics'.

I don't need to.  I'm a qualified Physics teacher.  If I ever go back to teaching, I just hope you don't turn up in one of my classes.

@Three-ColourSunburst ;

Three-ColourSunburst

Megii said:

Crucially, the body cannot vibrate until the signal has already been generated and amplified.

It's just not true - I know well from experience that with all my solid body guitars, the body does vibrate appreciably, even when the guitar isn't plugged in - I often practice this way, and I can both feel the body resonating, and hear an appreciable acoustic volume, even if it's not as loud as a full acoustic or semi-hollow instrument, it's definitely there. It's something I look for in what I would consider to be a good electric guitar.

As I said, what I meant was,

"Crucially, the body cannot be vibrated by the air in the room until the signal has already been generated and amplified."

Lescaster

I just want you all to know that I am so, so sorry.

Megii

Three-ColourSunburst said:

Megii said:

Crucially, the body cannot vibrate until the signal has already been generated and amplified.

It's just not true - I know well from experience that with all my solid body guitars, the body does vibrate appreciably, even when the guitar isn't plugged in - I often practice this way, and I can both feel the body resonating, and hear an appreciable acoustic volume, even if it's not as loud as a full acoustic or semi-hollow instrument, it's definitely there. It's something I look for in what I would consider to be a good electric guitar.

As I said, what I meant was,

"Crucially, the body cannot be vibrated by the air in the room until the signal has already been generated and amplified."

OK, agreed, but it matters not, the guitar body resonates an appreciable amount anyhow, without this effect from amplification - as I said, I know this well from experience.

andyp

Lescaster said:

I just want you all to know that I am so, so sorry.

Sorry, but this made me laugh more than it should've. I nearly posted about this Johan video on here as I love his stuff. I'm really glad I didn't.