myth-busting: Resonance is not synonymous with Vibration

[Deleted member 165050]

It can only diminish it, not support it, as the vibrations of the body are unlikely to vibrate the string again in phase with significant energy. And if it is imperceptible, I won't worry about it as I won't hear it.

Well that's just, like, your opinion. In all seriousness, in acoustics there is such a thing as constructive interference, which can affect SBG bodies just as much as destructive interference can. So just as some basses have dead spots, they can also have live spots. Or maybe that wasn't what you were actually talking about, I skipped out 5 pages back to mix a white russian...

 

[-Asdfgh-]

Well that's just, like, your opinion. In all seriousness, in acoustics there is such a thing as constructive interference, which can affect SBG bodies just as much as destructive interference can. So just as some basses have dead spots, they can also have live spots.

In acoustic instruments it makes more sense. With a big slab of material it's very hard to excite that into any sort of significant vibration so transference is limited. A thin flat plate (top of an acoustic) is another matter.

Or maybe that wasn't what you were actually talking about, I skipped out 5 pages back to mix a white russian...[/QUOTE

 

[chadds]

>>pro builder's take on this subject<<

Thanks for including that!

We are learning as a species why we believe what we believe. Does that belief reinforce some vision of ourselves for instance? "If I agree with that then I'm that sort of person." Our next step toward getting along will be when we accept that we all have different experiences. "Wow, he hears overtones in that Music Man bass that I don't." We argue the position instead of looking to see what limits our receptivity to new approaches.

 

[Deleted member 165050]

In acoustic instruments it makes more sense. With a big slab of material it's very hard to excite that into any sort of significant vibration so transference is limited. A thin flat plate (top of an acoustic) is another matter.

There are a couple of studies showing that bass guitar bodies are very prone to vibration, particularly the horns (which can vibrate in or out of phase with each other). It is really easy to prove how vibration transfers - just play a SBG while it's resting against or on a wooden table and see how it's much louder than if not touching anything - string vibration transfers through the wood of the solid guitar body and into the table wood, which acts as an amplifier. If the strings weren't significantly transferring energy into the guitar body that wouldn't happen.

 

[-Asdfgh-]

There are a couple of studies showing that bass guitar bodies are very prone to vibration, particularly the horns (which can vibrate in or out of phase with each other).

There are several on electric guitars. They vibrate, but it's not a huge amount of energy.

It is really easy to prove how vibration transfers - just play a SBG while it's resting against or on a wooden table and see how it's much louder than if not touching anything - string vibration transfers through the wood of the solid guitar body and into the table wood.

The human ear is non-linear, so it's actually quite quiet, just louder than the body itself, and you are creating a flat-plate resonator which is quite efficient, so demonstrates how little the body is vibrating as in terms of energy, it's a tiny fraction of the energy transfer of an ABG. It's a long time since I've tested it, though, to see how it might affect sustain. That might have to wait until I've moved and I have a table again. You can get a boost from resting the head of the instrument onto a wall, but there it's reducing the vibration of the neck by increasing stiffness, meaning more is heard from the strings. I am not sure to what extent resting it on the table is amplifying the signal from the body of the guitar or increasing overall stiffness. I'd have to think about how that could be tested. The issue is it might increase sound transfer (shortening sustain as it is robbed from the string) at the same time as increasing system stiffness (increasing sustain) so if sustain remained the same I might not know what had happened. I could put a contact mic on the body and if the signal dropped it might mean less transfer from the string (increased system stiffness) but then I'd also need to calculate the energy difference which means I'd need to weigh my table and a bass with all the hardware and neck taken off and assume the density was much the same. I might try with the Les Paul guitar kit as it's mahogany just like my coffee table I have to build it, though.

 

[-Asdfgh-]

Out of interest, I attached some self-adhesive weights all over the back of the Warmoth jazz bass's headstock, and it made the dead spot slightly worse (unscientific measurement by perceived differences since I lack a standardised plucking machine) but it stayed in the same location on the neck, which is antithetical to received wisdom, but perhaps the connection isn't sufficiently strong? The neck has steel reinforcements. I have a Fatfinger somewhere (chaos: moving house).

If recording in my 'studio' I might sometimes aim to rest the headstock on the desk to increase stiffness even more which fixes it. This reminds me to ensure the 'L' of the desk after moving or something else in the 'studio' allows this. If I go with the envisaged layout the desk will be the wrong way around but I can make an extra element of the double-decker guitar storage area something I can rest the headstock on for this purpose, very probably.

My first bass didn't have a dead spot. The second (Jazz bass copy) didn't either. Nor did the Squier JV, at least not that I noticed. It was my first real Fender that had one, and a doozy of one. The second one was a bit less but workable and handily on the 7th fret of a Cowpoke which meant that leaving the D string unfretted compensated for it a bit.

 

[Deleted member 165050]

There are several on electric guitars. They vibrate, but it's not a huge amount of energy.



The human ear is non-linear, so it's actually quite quiet, just louder than the body itself, and you are creating a flat-plate resonator which is quite efficient, so demonstrates how little the body is vibrating as in terms of energy, it's a tiny fraction of the energy transfer of an ABG. It's a long time since I've tested it, though, to see how it might affect sustain. That might have to wait until I've moved and I have a table again. You can get a boost from resting the head of the instrument onto a wall, but there it's reducing the vibration of the neck by increasing stiffness, meaning more is heard from the strings. I am not sure to what extent resting it on the table is amplifying the signal from the body of the guitar or increasing overall stiffness. I'd have to think about how that could be tested. The issue is it might increase sound transfer (shortening sustain as it is robbed from the string) at the same time as increasing system stiffness (increasing sustain) so if sustain remained the same I might not know what had happened. I could put a contact mic on the body and if the signal dropped it might mean less transfer from the string (increased system stiffness) but then I'd also need to calculate the energy difference which means I'd need to weigh my table and a bass with all the hardware and neck taken off and assume the density was much the same. I might try with the Les Paul guitar kit as it's mahogany just like my coffee table I have to build it, though.

Really you need high quality transducers as are used in vibration analysis and some accurate data capture and analysis software (A-weighted or otherwise), but the table acts as an amplifier purely because it's a flat resonant surface transferring received energy to the surrounding air. I know it's not that much louder but actually on my mahogany table it is significant with any solid body instrument. But not sure I'd use that rig for gigging

 

[-Asdfgh-]

Really you need high quality transducers as are used in vibration analysis and some accurate data capture and analysis software (A-weighted or otherwise), but the table acts as an amplifier purely because it's a flat resonant surface transferring received energy to the surrounding air. I know it's not that much louder but actually on my mahogany table it is significant with any solid body instrument.

If someone is willing to fund me for the kit and 2 days a week working on all this I am game.

But not sure I'd use that rig for gigging

I tried to rescue my grandmother's old mahogany table when she died to get a guitar made out of it.

 

[chadds]

This is good! I laid an Ashbory on a very thick soft bath towel, that I use when doing minor tweaks, on a 150 year old oak kitchen table. Plucked strings. The volume was huge and it sounded just like the Ashbory plugged in. There you have agathis a light not dense wood making whoopy with some serious oak with almost 1/2" of towel and air space being vibrated by strings with very little tension.

I mentioned micing a Telebass. What I did was put a thin towel on a piano bench to protect the bench. The mic a lowly SM57 was in a desk mic stand. The short ones with the round heavy bass. The bottom by the jack on a Tele was on the towel on the bench in a normal playing position. I sat on the bench. The airborne string vibrations were picked up by the capsule. The deep bass and low mids came through the base of the stand up through the body of the mic and together delivered quite a full performance. Now what kind of bench? How old was it? Varnish yes, not poly finish. There were some music books in it. I'd experiment with that. There were some finger artifacts that the mic picked up that added definition and aren't present when plugged in. Very wispy tops on everything.

 

[-Asdfgh-]

This is good! I laid an Ashbory on a very thick soft bath towel, that I use when doing minor tweaks, on a 150 year old oak kitchen table. Plucked strings. The volume was huge and it sounded just like the Ashbory plugged in. There you have agathis a light not dense wood making whoopy with some serious oak with almost 1/2" of towel and air space being vibrated by strings with very little tension

Is the table vibrating?

 

[chadds]

Is the table vibrating?

Absolutely.

In the piano bench technique had the mic been hung and in a suspension then there wouldn't have been a transference of the lower frequencies to the body of the mic.

 

[Deleted member 165050]

This is good! I laid an Ashbory on a very thick soft bath towel, that I use when doing minor tweaks, on a 150 year old oak kitchen table. Plucked strings. The volume was huge and it sounded just like the Ashbory plugged in. There you have agathis a light not dense wood making whoopy with some serious oak with almost 1/2" of towel and air space being vibrated by strings with very little tension.

I should probably have said that when I do the same thing I rest the wood of the bass guitar body directly against the wood of the table - no towels, just direct contact. Works best with the edge of a lower bout contacting the surface.

 

[chadds]

I should probably have said that when I do the same thing I rest the wood of the bass guitar body directly against the wood of the table - no towels, just direct contact. Works best with the edge of a lower bout contacting the surface.

Makes sense of course. The Ashbory was shockingly effective with that towel that’s why I reported it.

With the Piano bench it was a cloth diaper so “thinish” and only under the bass not the mic stand.

 

[Iristone]

Just occured to me, if pedagogy is the goal, than "Höfner" should be anglicized as "Hoefner", and pronounced "Herfner". Since Höfner (PS: and pedagogy) had been mentioned in this thread...

 

[mongo2]

There are a couple of studies showing that bass guitar bodies are very prone to vibration, particularly the horns (which can vibrate in or out of phase with each other). It is really easy to prove how vibration transfers - just play a SBG while it's resting against or on a wooden table and see how it's much louder than if not touching anything - string vibration transfers through the wood of the solid guitar body and into the table wood, which acts as an amplifier. If the strings weren't significantly transferring energy into the guitar body that wouldn't happen.

I've had a similar experience but playing with the headstock pressed against the sheetrock wall of the room while playing standing. It's a bit clumsy but there are no deadspots and a considerable volume and clarity increase.

 

[HaphAsSard]

Just occured to me, if pedagogy is the goal, than "Höfner" should be anglicized as "Hoefner", and pronounced "Herfner". Since Höfner (PS: and pedagogy) had been mentioned in this thread...

IIRC, not only is the spelling "oe" occasionally used by German speakers themselves on umlaut-less keyboards, but also the actual origin of the umlaut diacritic.
[More generally: an inline, "diacritic letter" ("-e" as in ae/oe/ue) used as a common way of rendering the umlaut sounds in centuries past, itself frequently executed as a superscript "e" over a/o/u which in turn eventually became identical to the diaeresis symbol.]

As for the "Herfner" pronunciation, it is indeed a decent English approximation of the German original if a non-rhotic accent is assumed (specifically, one with a central vowel in "hurt", as opposed to a syllabic "r" or a "hoit" -type pronunciation): much less so for most North American, Scottish or Irish accents ("Hurrrfnurrr")...
[Or so I'm told: I am not a native speaker of English.]

 

[-Asdfgh-]

I've had a similar experience but playing with the headstock pressed against the sheetrock wall of the room while playing standing. It's a bit clumsy but there are no deadspots and a considerable volume and clarity increase.

You get a lift in volume using a solid brick wall too, and that's not from the brick wall vibrating, it's from the increase in stiffness of the system meaning the neck isn't absorbing as much energy so you hear it from the strings more. Just to be sure, I double-checked it just now.

 

[mongo2]

You get a lift in volume using a solid brick wall too, and that's not from the brick wall vibrating, it's from the increase in stiffness of the system meaning the neck isn't absorbing as much energy so you hear it from the strings more. Just to be sure, I double-checked it just now.

Yes, it acts to restrict loss of energy due to neck movement. I also tried it on a brick wall and a cement block wall with the same results but I don't want to ding my headstock so I won't be doing that again.

 

[-Asdfgh-]

Yes, it acts to restrict loss of energy due to neck movement. I also tried it on a brick wall and a cement block wall with the same results but I don't want to ding my headstock so I won't be doing that again.

I tried on one that was at least plastered

 

[chadds]

I called my friend who used to do "Hunt for Red October." Hydro acoustics were part of his work. He said everything vibrates even on a subatomic level. Some surfaces are extremely reflective. Like singing in a marble bathroom. The vibration of objects is how we hear. It is how with your eyes closed you know that a metal spoon fell on the tile floor or on a carpet.

The energy from the bass is not enough to vibrate the brick wall enough to be audible. Adding stiffness to the bass was a possibly desirable effect. The oak table was easily receptive to being vibrated. You know that were you playing with a full band on the other side of that wall while your neighbor was sleeping your neighbor might complain. That wall is passing that sound through by being vibrated.

This is not an either or thing. It's an and thing. We want our instrument bodies to have characteristics that are dominant in support of the tone we want. Leo may have intended to use cheap swamp wood to mass produce instruments for sale. That after the fact musicians preferred certain characteristics was possibly unintentional. Now that luthiers can choose to mimic those characteristics we have available to us the kind of instruments we want.