myth-busting: Resonance is not synonymous with Vibration

[James Collins]

@ficelles Thank you for such an informative paper and lively conversation. I have read it and learned a whole lot.

Your paper you provided does not support your assertions and actually argues against your points.

A few things: The paper you supplied does not support your assertion about constructive and destructive interference. In fact, the words "constructive" and "destructive" don't even appear in the paper. The word "interference" does not either.


The paper does not agree with your definition of a live spot. You say:



The paper says:
A live spot, as defined by the regular decay of all partials dominated by internal damping, is found at the 10th fret; cf



The paper does not agree with your definition of a dead spot. You say:



The paper that you posted says:

Obviously, there is a close correlation between dead spots and the conductance. Where a dead spot occurs the conductance proves as high for the first partial

and

A dead spot occurs as soon as support damping dominates, which is selective with respect to location and frequency


The paper specifically says it's not talking about anything having to do with constructive/destructive interference. The closest it comes is talking about inharmonicity and out-of-phase vibrations in the string which I mentioned to you previouly:

Quote: The inharmonicity, which may originate from damping, is not considered in this report. The main scope is to analyse the decay of the vibrations. (note that by vibrations he means those in the string interacting by resonance of the neck and body of the bass)



Thank you!

The paper uses the word reactive instead of constructive interference. It doesn't address it other than to say it is one reason his model overestimates the number of dead spots and requires further study.

I don't really have time to read through a 100 page technical paper. Just glanced through what I thought looked like relevant sections and read the conclusions.

 

[BBQisgood]

The paper uses the word reactive instead of constructive interference. It doesn't address it other than to say it is one reason his model overestimates the number of dead spots and requires further study.

I don't really have time to read through a 100 page technical paper. Just glanced through what I thought looked like relevant sections and read the conclusions.

I did. I read quickly and I read several papers a week. It didn’t take very long but I enjoyed it.

He specifically says that he has not dealt with it. He analyzes the conductance of certain frequencies and concludes that live vs dead spots are influenced by whether the dampening of the wave happens fundamental up or higher secondary frequencies. Also talks about dampening intrinsically and in support structures in that context.

He does not say reactive interference. He refers to reactive admittance. He does not say he overestimates their number of dead spots. He says that he underestimated one small part of one component of time decay.

What you said earlier:

Constructive interference wouldn't make the string louder than when you first plucked it.

is 100% correct.

 

[Deleted member 165050]

@ficelles Thank you for such an informative paper and lively conversation. I have read it and learned a whole lot.

Your paper you provided does not support your assertions and actually argues against your points.

... lots of obfuscation

I'm just going to disagree with your conclusions.

Firstly, quibbling about terminology is nothing more than obfuscation. You obviously substituted "live spot" for "constructive interference" and "dead spot" for "destructive interference" so why devote so much verbiage to the minor issue of whether specific terms were used?

Secondly, the paper clearly defines the effect of those interferences in terms of decay time rather than relative volume. But the perception of the effect is the same. A dead spot sounds quieter as the note decays very quickly. A live spot sounds louder because it decays much more slowly. All relative to the majority of notes where no interference occurs.

Finally, re-interpreting selective text to claim the context of the paper isn't relative to the subject under discussion is nothing more than a shallow debating tactic. Obfuscation, re-interpretation, diversion.

I'm going to stand firmly by my assertion that constructive and destructive interference within a solid body instrument affects the amplified sound, and that this is proven by vibration analysis.

 

[BBQisgood]

I'm just going to disagree with your conclusions.

Firstly, quibbling about terminology is nothing more than obfuscation. You obviously substituted "live spot" for "constructive interference" and "dead spot" for "destructive interference" so why devote so much verbiage to the minor issue of whether specific terms were used?

Secondly, the paper clearly defines the effect of those interferences in terms of decay time rather than relative volume. But the perception of the effect is the same. A dead spot sounds quieter as the note decays very quickly. A live spot sounds louder because it decays much more slowly. All relative to the majority of notes where no interference occurs.

Finally, re-interpreting selective text to claim the context of the paper isn't relative to the subject under discussion is nothing more than a shallow debating tactic. Obfuscation, re-interpretation, diversion.

I'm going to stand firmly by my assertion that constructive and destructive interference within a solid body instrument affects the amplified sound, and that this is proven by vibration analysis.

No.

This isn’t obfuscation. No terms were redefined. Your problem is that you said

Destructive interference occurs within solid body bass guitars as has been proven by multiple formal studies and that interference is transmitted to the amplified sound. That is why basses have dead spots,

Those are your words. I’m not obfuscating by quoting you. You said that destructive interference causes dead spots. Then you posted a paper as proof that has nothing to do with it. Then you accuse me of conflating terms?

You also said

The decay on a constructive interference (live spot) frequency is much longer than a frequency where there is no interference, and with both those scenarios the decay is much longer than with a destructive interference (dead spot) frequency.

Again, you defined it that way, and not me. Yet you accuse me of conflating the terms?


You also said

As always, opinion is no substitute for formal education and experience.

Have you all done your homework yet? There will be a test paper later in the week...

On top of that, you use the name “idiot” in a later post to label those here who disagree with you. I let all that go.

I have been respectful and honest with you. Accusing me of obfuscation is an attack on my honesty and openness. Believe it or not, I care about that even on an Internet forum. (Talkbass might be the best).

It would have been great to have a good, two-way conversation about this. In the future, don’t knock others’ level of education. Some of the brightest I know don’t even have one. Also, some of the most educated you meet won’t toot their horn about it.

I’m disappointed.

 

[Killed_by_Death]

Maybe this will ring your bell:

the definition of to resonate is produce or be filled with a deep, full, reverberating sound.

Correct, so
if an instrument is vibrating, but NOT reverberating, it is NOT resonating!

This is the interweb. Keyboard commandos spouting opinions as if they are truth.

In this case, the commando pretended to know more than the rest of us, while presenting links to experiment reports that only confirm the fact from the OP.


This thread has been a big win, a lot of folks learned something. Only a few are left who simply can never concede, the 'We know what they meant!' crowd, supporting misnomers, no matter the cost.
The point of the exercise was to inform people, mission accomplished!

 

[Deleted member 165050]

.... stuff ...

You're not discussing science, you're arguing for the sake of arguing. And this discussion is now well and truly under the bridge, as per usual.

 

[James Collins]

Maybe this will ring your bell:

Correct, so
if an instrument is vibrating, but NOT reverberating, it is NOT resonating!

Yeah. It doesn't really change anything. I'm obviously missing something. I would again say this is cherry picking definitions. The point of language is to understand each other. Language has failed some of us I guess.

re·ver·ber·ate
/rəˈvərbəˌrāt/
verb

(of a loud noise) be repeated several times as an echo.
"her deep booming laugh reverberated around the room"

(of a place) appear to vibrate or be disturbed because of a loud noise.
"the hall reverberated with gaiety and laughter"

ARCHAIC
return or re-echo (a sound).
"oft did the cliffs reverberate the sound"

have continuing and serious effects.
"the statements by the professor reverberated through the capitol"

 

[-Asdfgh-]

According to that paper it's more a function of decay time than of making it louder. The decay on a constructive interference (live spot) frequency is much longer than a frequency where there is no interference, and with both those scenarios the decay is much longer than with a destructive interference (dead spot) frequency.

Yes, sorry, I was referring to the theory people have that the body vibrating will help sustain by vibrating the string. It assumes the transfer back will be in significant. The conductance will give an indication of the ease of transfer. Some of the vibration may be as a flat plate, so some chance of in phase vibration, perhaps, but a lot will just end up as heat.

 

[mtdkingstonheir]

This thread is making my head hurt! I just like playing my bass.