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Author Topic: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?  (Read 70977 times)

The Observer

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #15 on: July 25, 2009, 06:51:57 PM »
Swimmingcat,

First, welcome to the forum, cool name.
I am honored that you felt compelled enough to answer my question to sign up.

Second, thanks for spending the time to write a clear answer.

Third, I can tell you made a lot of your theories up and do not play acoustic guitar..
   
      Basically, you are saying that sound that would have gone behind the guitar is refocused (echoed) back to the front... and constructively interferes with the strings waves to make bigger waves on the front side and virtually no wave on the the back.

     Thus your explanation for louder sound with no extra energy.

     You mention Resonance. but do not account for it.

Although the statement, "the acoustic guitar is loudest near the hole" is true...
    It is also louder everywhere, including behind the guitar.
        As a person who has played for over 30 years, you will have to take my word for it.

You mention a loud speaker.
    You will be surprised to find out that I claim a loudspeaker is an overunity device !
        The reason is not as simple as this (the guitar)... as one must understand magnetic permeability
                 and comprehend that a speaker built using only coils takes far more energy
                       than using a magnet and a coil/wrapped around iron.

     Anyways, since you mention resonance but do not explain how it fits into the equation...
               I will offer a short explanation.

                   You need to understand what Forced Resonance is.

          a. Every object has a natural frequency(s) that it will vibrate at.
          b. One vibrating object can start another object vibrating (must use natural frequency).
          c. A small driving force can cause a large oscillation in the second object.
              This is because of the phenomenon that Resonant Systems STORE energy.
          d. The second object interacts with the real world in terms of the energy STORED.

In the case of the Acoustic Guitar.

         There are 2 objects...
 
         1. the string
         2. the air in the guitar

         The String (1.) is the small driving force mentioned above.
         The Air (2.) is the Resonant System that Absorbs Energy and has large oscillations.
         You and me are the real world that hears the result of a Vibrating Systems
                                         interacting with the world in terms of the Energy It Stored.

I will apologize for acting like a know it all... but you will find all this (and more cunundrums)
      in a regular college physics text book.

The Observer

swimmingcat

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #16 on: July 26, 2009, 02:33:57 PM »
I do not agree than a guitar or a loud speaker are over unity devices. They simply are efficient at producing sounds that the human ear responds to with the input energy (strumming or electrical signals respectively) provided. I would like to believe that they are over-unity, but your points are not able to provide enough sway.

Though I do have an open mind to over unity devices, they appear to be much like sasquashes - people have reported seeing them and there are even videos but none are available for close inspection. Without the scrutiny of others these stories just appear to be fanciful tales.

I challenge anybody to produce a set of plans for an over-unity device. I have access to a machines shop and an electronic technician. I can have it built - no problem.

The fact is that nobody can come up with such plans. All reportedly over-unity devices are shrouded in secrecy and all reports of their operation are uncorroborated - basically hear-say. I challenge anybody to provide me with an opportunity to examine an over-unity device or produce some plans to build one. I expect I will be waiting for a long long time.

Typical of the over-unit fair are documents like the MEG-patent:

http://www.cheniere.org/references/MEG_Patent.pdf

This document fails to give enough information to build a machine. It merely gives the inventors the right to take somebody to court who they think may have infringed on this patent. And if you find it confusing perhaps you could buy one of the dozen or so books ADVERTISED in the patent that supposedly explain the principles involved. I would put forward the notion that the intent of this document is to sell books.

One such book "The Final Secret of Free Energy" talks all around the subject with analogies. But the text never actually reveals any real physical phenomenon that demonstrate the principles. Where's the beef?

If the MEG actually worked and is really just a configuration of magnets, wire, and electronics then then far more money could be made by selling these machines than by selling books. Far more benefit to humanity could be gained by making small versions of this machine available to one and all to prove the concept to the world. And I would be happy to build them for the inventors to sell. They have a patent after all, and certainly would be entitled to royalties. But for some reason they prefer to sell books.
 


Paul-R

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #17 on: July 26, 2009, 03:51:50 PM »
What we need is a truly standard strum.

How about the "gizmo" used by Godley and Creme?
http://14.media.tumblr.com/PwCIEKd8Nm7mbw05kyEUJkdFo1_500.jpg

I think it was some sort of rotating arrangement of six shaving brushes
which stroked the strings, and gave infinite sustain. Then a microphone can record the actual sound level produced.

Don't forget to include a National guitar with the steel whatchamecallit
Paul.

ATT

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #18 on: July 26, 2009, 10:47:11 PM »
Step 1.          Realize a resonant system STORES energy.
Step 2.          Realize a resonant system can emanate energy.
Step 3.          Realize the energy emanated has to do with the energy stored.
.
With string instruments, the materials they're made of don't -store- energy, they -react- to energy (well, they store energy to 'burn' maybe).

OK, take a Les Paul, unplugged: Why doesn't it project much sound? Because the chunk of wood the strings are attached to requires a lot more energy than a vibrating string to move/vibrate much (the solid-body has a lot of 'inertia' to overcome).

Next, take a Martin D-28: Same string produces great sound. Why? because the
-thin- top/back/sides vibrate -more- with a lot -less- energy input (a lot less 'inertia' to overcome).

Moving right along, you take a 5-string banjo that uses a drum-head as a sound-board (less inertia, yet) and it's even -louder-.

The vibrations of the strings are transmitted, through both the 'nut' and the 'bridge', to the body of the guitar, the more the body reacts (vibrates), the more air is set into motion and the greater the SPL (sound pressure level).

Regardless of any sympathetic vibrations or standing-waves setup through various resonances that result from the selection and consistency of the materials chosen or their configuration in the instrument (which has more to do with 'timbre'), the primary reason for differing sound pressure levels is the relative degree of inertia between the two styles of guitar construction.

The easier it is to get the sound-board moving, the more air you're gonna push, the more volume you're gonna get.

If you want to get into phasing, standing waves and harmonics, that's also an interesting direction that will lead you more into tone than to SPL, but the original question about 'why' is one -louder- than the other follows the above tenets (at least with guitars, winds and brass are different animals).
 
Tony
.

ATT

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #19 on: July 26, 2009, 11:52:35 PM »
@Observer
You know, I don't necessarily disagree with the direction you seem to be taking with this thread because it is interesting stuff to ponder, but it would also be useful to run some practical bench-tests and gather a little data to mull over.

How much energy would you expend in intitiating the 'seed' vibration?
How much of the resulting SPL could you 'direct' twords a collector?
Upon collection, what means would you use to convert SPL to, say, electricity?
Compare converted-energy to initiating-energy and see if it still seems viable.

I've used an old Audio Cyclopedia (Howard Tremaine) for years (since '72) as a reference for sound, the 2nd edition of this volume is still available; ISBN 0672206757, if you're more interested in sound than the average guy.

There's been a fair amount of work done in piezo-acoustics for energy production/conversion, too, you may find some interesting directions to follow there, as well.

Tony
« Last Edit: July 27, 2009, 12:22:10 AM by ATT »

The Observer

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #20 on: July 27, 2009, 02:31:15 AM »
Swimmingcat,

     To understand that a speaker is overunity you need to understand Anisotropic Energy & Magnetic Permeability
          and how they pertain to ferromagnetic materials.

     In short, when a coil is wrapped around a piece of iron..
         the resultant magnetic field is
                      The Coil's Magnetic Field + The Iron's Magnetic field.

      And the Iron's magnetic field is 5,000 times that of the coil !!!!!!!

       I appreciate your rant...
                                          I think alot of people are skipping the basics.

                   That's why I am emphatic about this Resonance Thing.

Paul,
        Although a machine to do some strumming would be cool,
               It is undeniably true that an acoustic is much louder than an electric.
     
       However you brought up such a great point.
            National Guitar...
                   I discovered this last night when doing research.
 
      For those of you that don't know, In the 1920's they made super duper
         loud Acoustic Guitars because of problems of the band overpowering
            the guitar before electric amps.

      http://en.wikipedia.org/wiki/Resonator_guitar

      You know what they called it?

       A Resonator Guitar.

       hmmm... they made it louder by doing something with a Resonator !

      No kidding?
     
I'll be back,
                 The Observer

The Observer

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #21 on: July 28, 2009, 06:56:56 PM »
Utiltarian... from page 1 of this thread,

The sound is amplified, but the energy is not.  Without the soundbox of the acoustic guitar, the energy in the vibrating string would simply escape in another fashion.  With the soundbox, much more of the energy is converted to audible (and audibly pleasing) sound.  The soundbox does not magically amplify the energy, though; that would be impossible without some type of other input of energy, such as an electric amplifier.

You state the sound is amplified, but the energy is not?
             
          1. Higher amplitude waves come from a larger energy source.       

You mention the energy would escape in another fashion?

         2. Everything is the SAME except for the Acoustic Resonating Cavity.

You assert the sound box converts energy to audible energy.
 
         3. The sound box is actually an Acoustic Cavity Resonator.

On a side note. I stopped by the book store and read some Tesla books.
I was interested in exactly what he was going to do with Wardencliff.
Apparently there were going to be many uses, one of which was Free energy for all.
Wardencliff was actually smaller than the worldwide version, but in short...

Tesla wanted to put a radio frequency out that would Resonate in the Schumann Cavity ( a very specific frequency ).

That is , a small driving force (the tower) would cause a large oscillation in the resonator (the Schumann Cavity).
This large oscillation would then be tuned into for free energy by "large radios" dialed into that frequency.

Or using the guitar analogy...

          The Wardencliff Tower is the String.
          The Schumann Cavity is the Body of the Guitar.

Regards,
            The Observer

     `
       

The Observer

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #22 on: August 20, 2009, 05:50:40 PM »
I made an important discovery.

This discovery proves that two similar tuning forks (1 struck, 1 not struck) ring for a longer period
        than the case with just 1 tuning fork.
 
            This proof is important because naysayers and Wiki pages say the opposite is true !

1. Take an acoustic guitar and tune it perfectly... with a tuner if you have to.

   2. Strum the High E String.

     3. Damp the High E String.

       4. Observe an E still ringing.

5. Observe that the Low E and A Strings are vibrating. (Two Strings that were Not Plucked !)

6. Strum High E Sting with all other strings Damped.
 
    7. Time the length of sound from High E String (~6 seconds)

       8. Strum High E String without Damping any other strings.

          9. Time length of sound from High E, Low E and A vibrating... (~ 12 seconds !)

One final point is that it is louder with all vibrating too, however I havn't tested this with a decibel meter for definitive proof.

Please try this at home, this is reproducible proof that Free Energy exists in Forced Resonant Systems.
   It will happen every time, as long as the guitar is in tune.

                  Please let me know how this turned out for you. ;o)

                                                   ++
                                                    ll
                                                    ll
                                                    ll
                                                 (  O  )
                                                (____ )
                                           The Observer

mscoffman

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #23 on: August 20, 2009, 06:16:26 PM »

The acoustic guitar's body is designed to couple to ambient air
better then the electric guitar which is designed to couple better
to an electronic pickup. But...the resonant box of the acoustic
guitar is going into interfere with a number of "hot licks" and
offset tuning of an accomplished musician. So the acoustic
guitar is louder...but not necessarily better.

Which is louder; A big cone speaker in an acoustic chamber cabinet
or small cone speaker when driven with the same signal?

:S:MarksCoffman

MileHigh

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #24 on: August 20, 2009, 11:43:17 PM »
The Observer:

Quote
Please try this at home, this is reproducible proof that Free Energy exists in Forced Resonant Systems.

--------

I recently posted this response to someone else's statement about resonance:

The statement:

Shortly : ask yourself , how RESONANCE is at all is possible ? When you struck a rod at correct frequency and it sings very long - isn't that an unexpected miracle ?

The reply:

It's not a miracle because it's the same resonance ring-down that you see in an RLC resonant oscillator.  The stiffness of the rod is like a spring, and that represents the size of the coil.  The mass of the rod is like a capacitor - the speed of the moving mass is like the voltage across the capacitor, and the amount of mass is like the size of the capacitor.  The fact that the rod does not sing forever, is because there is some energy lost in the mechanical hysteresis loop of the rod.  This is like the resistance in the electrical RLC resonator.

When you hit the rod you put energy into it.  The rod stores that energy by singing.  The stored energy goes back and forth between the moving mass and the compressed spring.  When the mass is moving its fastest, the spring is completely decompressed, and all of the stored energy is in the moving mass.  When the mass has stopped moving, the spring is at it's maximum compression, and all of the stored energy is in the spring.

Just like in the electrical version the energy goes back and forth between the capacitor and the coil.  When the capacitor voltage is at it's maximum, there is no current in the coil, and all of the stored energy is in the capacitor.  When the capacitor voltage is at zero, there is maximum current in the coil, and all of the stored energy is in the coil.

So in both cases, energy is just going back and forth in a nice smooth sine wave pattern.  Resonance is just energy smoothly moving back and forth between two things that can store the energy.

At the same time, the form of the energy is always transforming back between two different states in a sine wave pattern.  In the above examples the two states are a moving mass and a compressed spring, and a capacitor with voltage across it and a coil with current going through it.

That is the key to understanding resonance and it applies to almost anything that resonates.  If you don't understand it, it is worth reading through until you do understand it.  The prize is five Brownie Points.

------

"Forced Resonance" would more aptly be described as putting energy into the resonant system, and then watching it decay out of the resonant system and transform itself into other forms of energy.  There is no over unity there, but it is a fun and fascinating study.

Can anyone see how this applies to the acoustic guitar example?

MileHigh

Bob Smith

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #25 on: August 21, 2009, 04:37:23 AM »
Quote
Can anyone see how this applies to the acoustic guitar example?

Mile High,
The rod's response to forced resonance is similar to the response of a decent guitar made from solid tone woods. A solid back, sides and top -and neck- will all resonate together, much like your rod example, until the resonance eventually subsides below the audible level.  Cheap guitars made with plywood back, sides, top and neck generally won't resonate this way.
Bob

MileHigh

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #26 on: August 21, 2009, 05:12:03 AM »
Hey Bob,

You are right and I will throw in lots of colour commentary.

The string is a resonator, the mass of the string per unit length is the capacitance, and the springiness or stretchability of the string is the inductance.

The air cavity is a resonator, where the mass of the air in the hole is the capacitance and the rest of the air inside the cavity acts like a compressible spring so that is the inductance.

Then the main body of the guitar is a resonator where the mass of the wood is the capacitance and the stiffness of the wood is the inductance.

So when you pluck a string, the initial energy in the string resonator starts being coupled to the resonators of the air cavity and the body of the guitar.  They look sort of like electrical transformers, and some of the initial vibrational string energy is coupled or transferred into the other two resonators with a certain coupling factor that is dependent on the frequency.

To be a bit more precise, the string is the driving source of the energy after it gets plucked and the other to resonators simply react, and act like filters.  In other words, the natural resonant frequencies of all three resonators are different.  So it depends on what note the string is playing to see how much the air and guitar body "filters" react to the stimulation.

In the end, you can cut the energy that your finger initially imparted into the string into two things, sound energy and heat energy.  Ultimately the sound energy becomes heat energy also.  Even the string itself heats up as you play it, there is some energy lost in the wire just like bending a coat hanger.

So you pluck the string, and after 10 seconds, all that you are left with is heat.  The resonance was just storing the energy for a short while, and it bleeds off and becomes heat.

MileHigh

The Observer

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #27 on: August 21, 2009, 05:32:49 PM »
Hey Mile High,

As far as I can tell, you have some decent knowledge when it comes to how resonant systems work.

The most important points that I am trying to impart to others are.

       1, What a Driven or Forced Resonant System is...
            (Small Giver of Energy ------> Receiver of Energy)

       2. How the Receiver in a Forced Resonant Situation receives and STORES ENERGY.

       3. How the Receiver of Energy vibrates at an amplitude congruent to it's STORED ENERGY.

       4. We FEEL/SEE/HEAR the vibrations that are the amplitude of the STORED ENERGY.

                         I would like you to respond to my guitar experiment.

In Summary... While the High E String vibrates for 6 seconds alone,
              the High E will start the Low E and A vibrating (if not damped)
                                                                           and all will ring for 12 seconds !


         If you wanna calculate Watts-seconds using...   Power=Intensity*Area*Seconds

         It is easy to see there is twice the energy ,and that's if it isn't louder... (which it is).

Have a nice day,
                           The Observer


MileHigh

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #28 on: August 22, 2009, 12:46:53 AM »
The Observer:

Quote
While the High E String vibrates for 6 seconds alone,
              the High E will start the Low E and A vibrating (if not damped)
                                                                           and all will ring for 12 seconds !

This is very similar to the string coupling it's energy to the air cavity and the body of the guitar.  In this case it's going from string to string.  I am not a guitar player buy are the High E and the Low E one octave apart?  If yes, then the Low E probably vibrates at it's first harmonic; the High E again.

The bottom line is that the energy drain to heat is slower.  Some of the energy moved over to some other strings, and that ended up extending the life of the oscillations.  From another viewpoint, you simply drained the power out of the oscillation more slowly, producing heat more slowly.

It may appear to sound louder because your ear is so sensitive to sound and you are dealing with the psychoacoustics of how you respond to the apparent volume of two strings vibrating at the same time.

MileHigh

The Observer

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Re: Why is an Acoustic Guitar so much LOUDER than an Electric Guitar?
« Reply #29 on: August 24, 2009, 02:41:15 AM »
Hello Mile High,

Thankyou for your response.

I agree that the other strings are vibrating at Harmonics of the High E.

But you say

   
Quote
The bottom line is that the energy drain to heat is slower. 
   Some of the energy moved over to some other strings,
    and that ended up extending the    life of the oscillations. 
   From another viewpoint, you simply drained the power out of the
   oscillation more slowly, producing heat more slowly.

Heat drain is slower?
 
    Come on... You will need to provide something vaguely specific here.

Energy moved over to the other strings?

    Well yes and no.
            Yes....Sound waves crossed the other strings and started them vibrating.
            No... No more energy left the Low E String to accomplish this !
                    (unless you count the energy coming back from all the resonators)

 Drained power out of the oscillation more slowly?

        Well, since the Resonators not struck... The Body of the Guitar... the Air in the Guitar,
             the Low E String and the A string... started vibrating..

                       They give off vibrations !!!
     
                             Yes it's true.
   
        And reinforce the system of aforementioned Resonators including the High E. 
 
                                       This is how it is working... is it not?

Finally, I had to look up psychoacoustics.

     You are saying that I am imagining that it is louder when all 3 strings vibrate.
     I say, yep, just like I imagine that the Acoustic Guitar is louder than an Electric.

Which brings me to my final point.

You say the human ear is sensitive?
   
       I would like to know how in God's good name you figure that?

Did you know the energy difference between 20 and 40 decibels is not 2 times more but 1000 times more.
In other words..  Normal conversation is over 1000 times louder than the library !

My point is... our ears are not sensitive, they need to be UNsensitive to cover the range of volume that they do.

          My next post will include a College Text Book Proof that the waves emitted from an Acoustic Guitar
                            are indeed 1000 times more Powerful than those from an Electric Guitar.

                                                                     The Observer