#1
I've been wondering this for a while:

How does a hollow body electric guitar create a different sound through an amplifier than a solid body electric guitar (assuming they have the same pickups). Theoretically, shouldn't they sound the same? An electric guitar pickup is just a solenoid, so the current should only be affected by the vibration of conductive objects (strings, in this case), not acoustic sound waves resonating in the body.

I assume the only way a hollow body can change the sound in this case is if the resonating body affects the strings' vibrations. Otherwise, I don't see how any sort of acoustic resonance can affect the flow of current and, therefore, the sound produced by the amplifier.

Does anyone have a good physical explanation of what causes the sound difference?

I promise I am not just some jerk who is trolling the forums. I really am curious.

Thanks!
#2
Think about it. Strings aren't the only thing resonating - everything the strings touch resonates. The string touches the nut and the bridge, which are mounted in the wood. Strum your guitar and put it up against your wall (or even easier, just touch your headstock). Simplest test to disprove your assumptions.
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Last edited by Offworld92 at Dec 22, 2011,
#3
But the strings are the only conductive objects that are resonating enough to cause a fluctuation in the magnetic field of the pickups. Any non-conductive objects that resonate shouldn't affect the magnetic field.
Last edited by saxman42 at Dec 22, 2011,
#4
The vibration feeds back differently depending on shape, density and what not. The body's vibration alters the bridge vibration, which in turn alters the strings vibration.

Basically: what your pickup picks up is what is essentially a collective vibration between strings, body, neck, nut and bridge. Even though its only the string that it picks up, but the string is affected by the rest because it is rested upon and reliant of the others' vibrational coefficient.
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Last edited by MonsterOfRock at Dec 22, 2011,
#6
Quote by saxman42
But the strings are the only conductive objects that are resonating enough to cause a fluctuation in the magnetic field of the pickups. Any non-conductive objects that resonate shouldn't affect the magnetic field.

They don't affect the magnetic field, they affect the vibration of the strings. Different construction methods and woods will create patterns of resonance in the strings, damping certain frequencies.
#7
Quote by saxman42
But the strings are the only conductive objects that are resonating enough to cause a fluctuation in the magnetic field of the pickups. Any non-conductive objects that resonate shouldn't affect the magnetic field.

Exactly. But the different vibrations from different materials, shapes and construction feed back into the string, and affects how the string vibrates. As such, the pickup simply picks up what the strings do, and no more... but the string's vibration is coloured by the instrument.
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#8
Quote by saxman42
I assume the only way a hollow body can change the sound in this case is if the resonating body affects the strings' vibrations.

spot on - you've answered your own question
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#9
Wow. Thanks for all of the replies! I think it's interesting how much body construction can actually change how the strings vibrate. I've always been under the impression that your pickups and the rest of your electronics are responsible for 90+% of the sound in an electric guitar.
#10
Quote by saxman42
I've been wondering this for a while:

How does a hollow body electric guitar create a different sound through an amplifier than a solid body electric guitar (assuming they have the same pickups). Theoretically, shouldn't they sound the same? An electric guitar pickup is just a solenoid, so the current should only be affected by the vibration of conductive objects (strings, in this case), not acoustic sound waves resonating in the body.

I assume the only way a hollow body can change the sound in this case is if the resonating body affects the strings' vibrations. Otherwise, I don't see how any sort of acoustic resonance can affect the flow of current and, therefore, the sound produced by the amplifier.

Does anyone have a good physical explanation of what causes the sound difference?

I promise I am not just some jerk who is trolling the forums. I really am curious.

Thanks!

this.

EDIT: lol after actually scrolling through the replies, I notice that others have highlighted/or something the exact same thing
#11
The posts above have it right - the body affects things to the extent that it affects the dynamics of the string vibrations that are being detected by the magnetic pickups. Since the pickups detect movement of the metal strings in relation to the pickup, there may also be a second-order effect from the pick-up itself vibrating.

As kind of a side comment - this is why piezo-electric pickups are used to more accurately reflect the sound of acoustic and hollow-body guitars. Since they basically respond to vibration of any kind, and not just of metal objects. They therefore respond to the vibrations of the soundboard/top, as transmitted from the strings and through the bridge.
#12
the construction of the guitar impacts how the strings resonate. even though it doesn't necessarily affect what the pickups sense (though, try tapping parts of your guitar with a screwdriver, you may be surprised by what you hear through your amp), the effect on string resonance has a huge effect on the sound of the amplified signal