Body wood affects tone

richardhomer

Sassafras said:

Three-ColourSunburst said:

Post deleted because, whist I was awaiting for this post to be 'approved' I had already answered the points raised (including the ones made by NelsonP just above) by editing an earlier post on this page. 

To close. If there really are 'many more' academic papers out there showing that 'tone wood' in solid-body electric guitars really does have an effect, then I would love to read them. There you go, prove the case! Anyone up for the challenge? I have already done all I can to try to find an definitive answer. 

Done all you can???
I don't think you're taking this seriously enough.

Never had him down as a quitter!

Gassage

richardhomer said:

Sassafras said:

Three-ColourSunburst said:

Post deleted because, whist I was awaiting for this post to be 'approved' I had already answered the points raised (including the ones made by NelsonP just above) by editing an earlier post on this page. 

To close. If there really are 'many more' academic papers out there showing that 'tone wood' in solid-body electric guitars really does have an effect, then I would love to read them. There you go, prove the case! Anyone up for the challenge? I have already done all I can to try to find an definitive answer. 

Done all you can???
I don't think you're taking this seriously enough.

Never had him down as a quitter!

How's Tarporley looking?

NelsonP

Gassage said:

richardhomer said:

Sassafras said:

Three-ColourSunburst said:

Post deleted because, whist I was awaiting for this post to be 'approved' I had already answered the points raised (including the ones made by NelsonP just above) by editing an earlier post on this page. 

To close. If there really are 'many more' academic papers out there showing that 'tone wood' in solid-body electric guitars really does have an effect, then I would love to read them. There you go, prove the case! Anyone up for the challenge? I have already done all I can to try to find an definitive answer. 

Done all you can???
I don't think you're taking this seriously enough.

Never had him down as a quitter!

How's Tarporley looking?

...and thanks for all the fish

Cirrus

OK, I did my Science Experiment while the drummer was setting his kit up at the start of practice.

Aim: To find out whether an electric guitar pickup "hears" vibrations coming through the body of the instrument.

Hypothesis: The strings make the guitar body resonate in a way that will generate a signal in guitar pickups even when the direct electrical current generated by the strings vibrating in the pickup's magnetic field is removed from the equation.

Method: A double neck guitar was used for the experiment. My drummer's dad built this kit. I plugged the guitar into a Vox ac30 amplifier set with the gain at around 1/4 for a relatively uncompressed clean but loud sound. With all volume and tone controls at max and bridge pickup selected for the 6-string neck, I strummed the top, 12 string neck in a typical guitar playing style with full chords, ignoring the fact that I was utterly unable to get it in tune because, well, it was my drummer's dad's first attempt at a kit guitar and also the strings are a bit buggered. I then switched to the 12-string pickups to establish how much of a volume difference there was between the sound coming through the 6 string pickups removed from the vibrating strings and the direct sound of the 12-string pickups underneath the vibrating strings. Having done this, I reversed the procedure - strumming the 6 string neck and listening to the 12-string pickups.

Possible errors: It's possible that the vibrations from the 12-string side could excite the strings on the 6-string neck, making them vibrate which then generate a signal in the 6 string pickups in the conventional, expected way. I decided to do the test in two ways. Firstly, by muting the strings on the un-strummed neck so they could not vibrate. For muting the top neck, I used the bottom of my head between my chin and throat. This did not suffice for the bottom neck as I am not a fucking acrobat, so I used a sock. Secondly, with the unused strings free to vibrate, as this would still demonstrate that energy could travel through a bridge and nut, into the guitar body, and back through the other bridge+ nut to influence how those strings moved.

It's also possible that the pickups in the guitar are unusually microphonic and hence generate an indirect through-body signal higher than would be typical. To test this, I stomped on a Bogner Burnley distortion pedal with the gain up, tried to get squealing feedback, and satisfied myself that the pickups fell into the normal range and weren't unduly microphonic.

Result: With the strings on the unstrummed neck muted, the pickups under those strings did generate a signal when the other neck was strummed. It was a warm, muted, bassy sound. It was also bloody quiet. I'd say that if the direct signal was in the 100-105dB range at my playing position, the indirect, through-body-only signal was about 45-50dB at most. This I judged by the conversation my drummer and bassist were having at about 60dB (typical range for human speech), and the fact I've measured my AC30 with a dB meter at those settings before at it tends to be in the 105-110dB clean range.

With the unused strings unmuted, the indirect signal was louder and brighter, maybe getting closer to 60dB. So the unused strings were definitely being excited by the vibrating ones on the other neck when they were free to vibrate in sympathy. I suspect this effect would have been stronger if I'd been able to get both necks in tune.

Conclusion: The experiment seems to show that yes, vibrations travelling through the body do generate a signal in guitar pickups. Moreso if the strings are also free to resonate in sympathy with the body. However, more study needs to be done as to how much of an effect this has relative to the direct signal generated by the vibrating strings themselves as it seems this indirect signal is approximately 40-60dB lower. My suspicion is that in typical playing it will be closer to the loud end of that range as in a typical single-neck electric guitar, the string being played is by nature not being muted, so is free to have its vibration influenced by energy coming back through the bridge.

crunchman

So @Cirrus has established that vibrations from strings cause the wood to vibrate, and that causes the other strings to vibrate in a way that is audible through the pickups.  Not very surprising but we now have proof of what most of use already knew.

This kind of wrecks one of the conclusions of the study that @Three-ColourSunburst quoted repeatedly when they said that the effect of vibrations travelling into the wood was negligible.  Whether it completely discredits the whole of it, I'm not sure, but it does make you seriously question their competence as researchers.

On a single neck guitar, obviously the vibrations will be fed back into strings that are already vibrating, so you will then wind up with all kind of complex effects due to phase issues.  Some frequencies will be reinforced, while others will cancel out.  The effect of construction and dimensions will be a lot bigger than the effect of the wood, but if the wood does selectively filter certain frequencies, it will have an effect - which is what those of us who have played lots of guitars already know.

It's not just frequency dependent though.  I think that the conversation yesterday about the transients, and the envelope of the note was definitely on the money.  Different guitars have very different responses.  Two of the same model can have very different responses.  You can hear it acoustically (unplugged) as well.  It's not just about whether the pot values are a bit different or one set of pickups has a few more winds.

Three-ColourSunburst

Cirrus said:

 It's possible that the vibrations from the 12-string side could excite the strings on the 6-string neck, making them vibrate which then generate a signal in the 6 string pickups in the conventional, expected way. I decided to do the test in two ways. Firstly, by muting the strings on the un-strummed neck so they could not vibrate. For muting the top neck, I used the bottom of my head between my chin and throat. This did not suffice for the bottom neck as I am not a fucking acrobat, so I used a sock.

So said chin / sock absolutely negated any chance of the non-strummed strings vibrating?
 
Edit. I have just read through your experiment again and am not entirely clear about what you did. I'll come back in a moment when I have gone through it again.

Cirrus

Three-ColourSunburst said: In fact, I would bet that 40-60dB signal you detected was entirely due to the only partially muted strings above the pickup vibrating in response to you cranking it out at 100-105dB!

No.

Read it again.

You've not understood what happened.

crunchman

@Cirrus - I suspect that whatever you say he won't believe you as it doesn't fit his pre-defined views.

Any reasonable person reading this thread will come to a sensible conclusion based on what you have done, and on what a large number of expert guitar builders have said.  Talking of expert guitar builders, there was a recent TGP thread where Terry McInturff said some good stuff on this topic as well.

I said it before, but I really am out of this thread now.  It is is just going round in circles.

MartinB

Cirrus said:

Three-ColourSunburst said: In fact, I would bet that 40-60dB signal you detected was entirely due to the only partially muted strings above the pickup vibrating in response to you cranking it out at 100-105dB!

No.

Read it again.

You've not understood what happened.

Your observations can not have any validity unless you are a professor in acoustics, or you agree with him.  Either will do...

Cirrus

My post-grad was in Internet Arguments with Someone who is Wrong, so I assure you I'm well qualified for this thread. 

impmann

Cirrus said:

My post-grad was in Internet Arguments with Someone who is Wrong, so I assure you I'm well qualified for this thread. 

So should that be Dr Cirrus, then?

Three-ColourSunburst

OK, back again. So, to clarify. What you are saying is that when you played one neck, the body vibrated, this caused the pickup to vibrate and because the magnets sat under some (at least partially) muted strings, as the pickups vibrated they produced a feint signal, 45-50 dB 'at most'. With the same amp settings, the sound level of a 'direct' signal was 100-105dB?

That all sounds perfectly reasonable, but I don't see how it really supports the 'tone wood' hypothesis. For example, as you say the indirect signal was 'warm', 'muted' 'bassy' and 'bloody quiet'.  So, it was to far too low a level to be heard over any direct signal and also seemed to have a harmonic response that could not account for the tonal qualities attributed to 'tone wood', with only the bass part of the spectrum coming through.

As to whether this vibration-induced signal is 'negligible' or not. Decibels are a logarithmic unit, so a signal of 50 dB has a power ratio of 1:100,000 as compared to a signal of 100dB. Also, this was for a strummed chord, so the signal for a single string / note would be much lower still.

Overall, even given that such a signal can be generated, this does not validate the 'tone wood' hypothesis. Firstly, the signal generated is very weak, having around 1:100,000th the power of a directly generated signal.

Secondly, the demonstration does not show that the signal affects the distribution of harmonics on all fretted notes in a way that gives the instrument a characteristic timbre. In fact it appears to do the opposite.

I would suggest that the 'bassy' response you got was simply because the bass strings vibrate the body more than the higher strings, having more mass. The 'tone wood' hypothesis argues that tone wood determines the timbre of all the notes. Your test suggests this is not the case, as the degree to which the body is forced to vibrate depends on the energy put into it, and the energy will be higher for the bass strings. In turn, any signal generated via the route you suggest would be much, much less for the higher strings.  (If you do it again, try to see if you can generate a signal by just playing the top E.)

A good contribution to the debate though!

Edit. We also need to bear in mind that this path of signal generation is very different to the one most commonly argued for by those who believe in 'tone wood'. They commonly argue that the string and body 'resonate' together, with the 'feedback' to the string passing via the bridge. It is the transmission of energy via this pathway energy that researchers such as Fleischer have described as being 'negligible'.

Three-ColourSunburst

Cirrus said:

Read it again.

You've not understood what happened.

Quite right. I realised that as soon as I posted. See my corrected response above.

Cheers!

NelsonP

Cirrus said:

OK, I did my Science Experiment while the drummer was setting his kit up at the start of practice.

Aim: To find out whether an electric guitar pickup "hears" vibrations coming through the body of the instrument.

Hypothesis: The strings make the guitar body resonate in a way that will generate a signal in guitar pickups even when the direct electrical current generated by the strings vibrating in the pickup's magnetic field is removed from the equation.

Method: A double neck guitar was used for the experiment. My drummer's dad built this kit. I plugged the guitar into a Vox ac30 amplifier set with the gain at around 1/4 for a relatively uncompressed clean but loud sound. With all volume and tone controls at max and bridge pickup selected for the 6-string neck, I strummed the top, 12 string neck in a typical guitar playing style with full chords, ignoring the fact that I was utterly unable to get it in tune because, well, it was my drummer's dad's first attempt at a kit guitar and also the strings are a bit buggered. I then switched to the 12-string pickups to establish how much of a volume difference there was between the sound coming through the 6 string pickups removed from the vibrating strings and the direct sound of the 12-string pickups underneath the vibrating strings. Having done this, I reversed the procedure - strumming the 6 string neck and listening to the 12-string pickups.

Possible errors: It's possible that the vibrations from the 12-string side could excite the strings on the 6-string neck, making them vibrate which then generate a signal in the 6 string pickups in the conventional, expected way. I decided to do the test in two ways. Firstly, by muting the strings on the un-strummed neck so they could not vibrate. For muting the top neck, I used the bottom of my head between my chin and throat. This did not suffice for the bottom neck as I am not a fucking acrobat, so I used a sock. Secondly, with the unused strings free to vibrate, as this would still demonstrate that energy could travel through a bridge and nut, into the guitar body, and back through the other bridge+ nut to influence how those strings moved.

It's also possible that the pickups in the guitar are unusually microphonic and hence generate an indirect through-body signal higher than would be typical. To test this, I stomped on a Bogner Burnley distortion pedal with the gain up, tried to get squealing feedback, and satisfied myself that the pickups fell into the normal range and weren't unduly microphonic.

Result: With the strings on the unstrummed neck muted, the pickups under those strings did generate a signal when the other neck was strummed. It was a warm, muted, bassy sound. It was also bloody quiet. I'd say that if the direct signal was in the 100-105dB range at my playing position, the indirect, through-body-only signal was about 45-50dB at most. This I judged by the conversation my drummer and bassist were having at about 60dB (typical range for human speech), and the fact I've measured my AC30 with a dB meter at those settings before at it tends to be in the 105-110dB clean range.

With the unused strings unmuted, the indirect signal was louder and brighter, maybe getting closer to 60dB. So the unused strings were definitely being excited by the vibrating ones on the other neck when they were free to vibrate in sympathy. I suspect this effect would have been stronger if I'd been able to get both necks in tune.

Conclusion: The experiment seems to show that yes, vibrations travelling through the body do generate a signal in guitar pickups. Moreso if the strings are also free to resonate in sympathy with the body. However, more study needs to be done as to how much of an effect this has relative to the direct signal generated by the vibrating strings themselves as it seems this indirect signal is approximately 40-60dB lower. My suspicion is that in typical playing it will be closer to the loud end of that range as in a typical single-neck electric guitar, the string being played is by nature not being muted, so is free to have its vibration influenced by energy coming back through the bridge.

Damn - it seems you can't award both a LOL and a wis for the same post, so have a wis (although the bit about not being a fucking acrobat did actually make me laugh out loud).

You should submit this paper for peer review. It's much more entertaining that most of the dross that gets published! And thank you for being so diligent with the experiment during valuable rehearsal time. I only hope that your next gig is brilliant!

On the results / conclusions:

"With the strings on the unstrummed neck muted, the pickups under those strings did generate a signal when the other neck was strummed. It was a warm, muted, bassy sound. It was also bloody quiet" - interesting finding. This is could be due to the 'unstrummed' pickups vibrating with the body while the muted strings above them are held still. That could generate a change in the electric field which may be sufficient to create an audible signal?

"With the unused strings unmuted, the indirect signal was louder and brighter, maybe getting closer to 60dB. So the unused strings were definitely being excited by the vibrating ones on the other neck when they were free to vibrate in sympathy. I suspect this effect would have been stronger if I'd been able to get both necks in tune." - agreed

Conclusion - agreed. This suggests that the mechanical impedance between strings and body is in fact not sufficient to prevent all of the vibrations from entering the guitar body (this we knew already), and crucially it also can affect the output at the pickups.

So if vibrations are passed to the body and they are audible via the pickups, do different woods pass these vibrations in different ways depending on their density and stiffness? Answer = probably.

It would be interesting to conduct the same experiment using a modeller and output to headphones, just to completely isolate any speaker effects. But your band mates will think you are a nutter and you have already made your contribution to 'Fretboard Science' 1.01.

dindude

Nice experiment, well done.

Isn't the definitive experiment: using the same bolt on neck, pickup and hardware - strapping it all to say an Ash tele body - recording the results. strapping it to a mahogany Tele body - recording the results. then strapping to anything (coffee table / mother in law) - recording the results. Then see if they sound the same.

WezV

dindude said:

Nice experiment, well done.

Isn't the definitive experiment: using the same bolt on neck, pickup and hardware - strapping it all to say an Ash tele body - recording the results. strapping it to a mahogany Tele body - recording the results. then strapping to anything (coffee table / mother in law) - recording the results. Then see if they sound the same.

sadly not - the act of taking them apart and putting them back together introduces variables.   Although I would say it gets you pretty close if you make sure you control string height above the pickup and break angle at the bridge

Three-ColourSunburst

dindude said:

Isn't the definitive experiment: using the same bolt on neck, pickup and hardware - strapping it all to say an Ash tele body - recording the results. strapping it to a mahogany Tele body - recording the results. then strapping to anything (coffee table / mother in law) - recording the results. Then see if they sound the same.

Funny you should say that, just such a 'definitive' experiment has already been done. Conclusions? 'Tone wood' is a myth.

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.

Abstract.

Nine electric guitar bodies were built in the form of the Telecaster model by the author RMP. These were assembled using the same neck and pickup assembly. Once each body was assembled two strings of the electric guitar were mechanically excited and the sound, obtained directly from the instrument, was recorded for later analysis. Also recorded was a musical piece played with each electric guitar. These sounds were analysed via a Fourier transform in order to obtain the component harmonics of the sound, these harmonics are responsible for the timbre of the instrument. The harmonic spectra of each electric guitar were compared to each other and there were no significant differences between them. Thus the variations of timbre of electric guitars, according to the results obtained here, depend on other factors than the wood of the body itself, a fact that arises from the absence of a significant coupling between the string and the body of the instrument. 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.

http://physicae.ifi.unicamp.br/index.php/physicae/article/view/physicae.9.5/116

https://physicae.ifi.unicamp.br/physicae/article/view/154

WezV

NelsonP said:

Cirrus said:

Result: With the strings on the unstrummed neck muted, the pickups under those strings did generate a signal when the other neck was strummed. It was a warm, muted, bassy sound. It was also bloody quiet

interesting finding. This is could be due to the 'unstrummed' pickups vibrating with the body while the muted strings above them are held still. That could generate a change in the electric field which may be sufficient to create an audible signal?

it could be - I think you have to still assume the muted string is not totally still, so can't say if the small signal if from string movement or pickup movement.   I assume its most likely both

Although its clear either one of those can only be explained by understanding the vibration in the body first

bacchanalian

" For muting the top neck, I used the bottom of my head between my chin and throat. This did not suffice for the bottom neck as I am not a fucking acrobat, so I used a sock."

I did not want to Lol such a useful post but I nearly pissed myself having read this.

Where did you get the sock?

richardhomer

@Gassage - I’m in Salford today - only 10 degrees and cloudy....