Do the acoustic properties of an electric guitar matter?

Whitestrat

New member
Here's some food for thought:

There's an age-old debate on guitars on whether a guitar's acoustic properties matters when you plug in the guitar and play it through an amp. Some say yes, some say no.

To me, it does matter. You have to separate the effect of the electronics over the natural sound of the wood. Terry McInturf said it best before as a ball park analogy:

The acoustical nature of the electric guitar's chassis imposes firm boundaries upon what the guitar can sound like amplified.

Think of the acoustical sound as being the fence around the perimeter of a ballpark; within this boundary, we can emphasise/de-emphasise certain frequencies by means of different pickups, strings, etc etc.

But we can never leave the ballpark.

For the resultant tone plugged in, there are many factors. not just the electronics, but something called sympathetic oscillations. There's a famous watch by Swiss Watchmaker FP Journe called the Resonance. It demonstrates sympathetic oscillations by having 2 completely independant but identical "pendulums" connected by a single bridge. The result is while both are oscillating at different frequencies, they will synchronise with each other in a matter of seconds, and both pendulums will move in perfect synchrony. This concept was first discovered and actualised by Abraham Louis Breguet (another famous watchmaker) back in 1795.

This sympathetic oscillation can also be found in guitars where the strings vibrate, and the guitar vibrates along. This vibration also moves the pickups (the main reason why unpotted humbuckers in hollowbody guitars squeal at high gain and feedback easily) and this results in a clash of vibration frequencies because both items are of different masses. This changes the way the pickups will react to the string vibrations and the singals it will produce. If the guitar doesn't vibrate, the resultant tone generated by the pickups will also be different, hence guitars can tend to sound a bit "warmer" when the pickups are potted. (cover capacitance aside)

An acoustically dead guitar will produce tones which are mostly dependant on the properties of the pickups. This is why Joe Satriani insisted in the beginning, a guitar from Ibanez which is acoustically "dead". He wanted the pickups to do the work more than the guitar. In such cases where the guitar is acoustically dead, and you get great tone plugged in, it's mostly the pickups and electronics that are at work. Changing the pickups will change the tones completely. A resonant guitar will produce tones which are a combination of the guitar's vibrations and the pickups processing capabilities. Changing the pickups will change the tones, but the inherent character (the ballpark Terry mentioned) will still be there.

I for one believe it is linked, but is not entirely crucial to choosing a guitar. It all depends on what you are looking for in a guitar. For me, the way to test guitars acoustically is not to strum the guitar wildly. It's not a test of your skill or chord vocabulary that you want to achieve here. More importantly, it is the single note quality and the multi note quality of the acoustic sound that's on show here.

Next time, try this: Bring the said guitar to a very quiet room. Pick 3 different notes on each string, low, medium and high. One string at a time. Softly, such that the strings don't hit the frets. All 3 notes on the same string should demonstrate the same decay properties. And for me, the key to a good acoustical tone, is the roundness of the note as it decays. It should be a "dooo" sound rather than a "eeeh" sound as it decays. If this almost vocal-like quality apprears on all strings at 3 positions, then you have a well made guitar where all the woods used are working in harmony. Same applies for chords. Use full barre chords, and you should hear the same qualities.

That's how I judge a guitar, at least.
 
Wow great input, Lionel. I agree with the points stated above. After all, a plastic electric guitar will never sound like a wooden one.
 
Thanks for sharing!

Just wondering : does "acoustically dead" equate to "acoustically neutral"? From the Satch example, the JS, being a basswood bodied guitar, is acoustically neutral.

Also, I did notice years ago that on some guitars, certain notes will "die" out faster than others, like the low G# on my old, cheapo Yamaha acoustic. It felt like it was dampened; the decay was significantly faster than the other notes. I'm sure it's nothing to do with setup/action problems. Could this have something to do with sympathetic oscillations? So from then on, I test guitars by playing on every fret on every string to make sure there are no dead spots. The sustain/decay should be consistent throughout.
 
yeah whitestrat thanks for sharing, exactly what people around this forum need to know!
 
If you think about it, let us go to one extreme. Imagine a guitar made of styrofoam. Any note you play would likely have it's vibrations be soaked up by the styrofoam and die off very quickly.

We can probably deduce that as we slowly increase the density of the material, there would be less vibrations lost to the material of the body.

Wood is a funny animal though. A plank of wood does not have a consistent property throughout. So at certain points, there may be properties that soak up certain frequencies.

I believe, as you say, Satch was looking for a material that would provide a consistent affect on all frequencies.
 
Just wondering : does "acoustically dead" equate to "acoustically neutral"? From the Satch example, the JS, being a basswood bodied guitar, is acoustically neutral.

"Acoustically dead" was Satch's exact words. I think you're right. "Acoustically neutral" might be more accurate?

We can probably deduce that as we slowly increase the density of the material, there would be less vibrations lost to the material of the body.

I wouldn't say that as a straight off rule. I remember a luthier once made a guitar out of Balsa Wood, and apparently, it was highly resonant... So I'm not sure it's got anything to do with density.
 
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I wouldn't say that as a straight off rule. I remember a luthier once made a guitar out of Balsa Wood, and apparently, it was highly resonant... So I'm not sure it's got anything to do with density.

I think we need to be clear on some word use too...

Resonant = ?
1. Increased sustain?
2. Echo from within the wood, suggesting chambers / pores in the right place?

Denser wood do increase sustain, whereas a wood that has the correct "chambers / pores / imperfections" might create the acoustics sounds that we like so much. ^.^ (Do correct me if I'm wrong though.)
 
You are confusing sustain with resonance. Resonance is physical vibration at a certain frequency. Sustain is inefficient energy transfer. A resonant guitar might not sustain well. Or it might. They are not entirely linked. Resonance will most likely impact resultant tone. Sustain is totally different, and has to do with how much energy is lost during transfer. Don't mix the 2.

Dense wood does not necessarily increase sustain either. It's about energy transfer. For example, consider this. Despite the sympathetic oscillation phenomenon, think of this: 2 bells connected by a very short 10cm plastic chain. Strike one, and the other will not move at all. However, connect the 2 bells with a simple metal rod, even though it's 10 feet long. Strike one, and the other will move.

So it's not just about how close the molecules are (a shorter rod will make it move more; less energy loss), but rather, the nature of the bonds between molecules. That delves into harmonic and frequency response of materials, which is another totally different subject.
 
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I don't think it really matters. After all, many people play their guitars thru tons of effects before the amp that one could not even tell even what tone wood the guitar is made of.
 
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