Tell me more ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free, no registration required.

If the pickups are just electromagnets detecting vibrations in metal strings, what effect does the guitar (size, shape, type of wood, solid body, hollow body) have on the pickups?

Most argue that the pickups are similar to microphones. However, direct contact with the pickup by material other than metal does not produce any significant sound from an amplifier.

How can wood vibrations from the body effectively transfer to the electromagnetic pickup to affect tone in a significant way?

share|improve this question

4 Answers

up vote 9 down vote accepted

I think the best way to think about this is to not only think about the wire (moving guitar string) cutting through the magnetic field of the pick-ups (stationary) but also to think about the pick-ups themselves moving with the resonance of the wood that they are fixated to.

Now you must consider the frequency response of the instrument as a whole and this would definitely be affected by the choice of wood. How much it affects the sound is another question. I personally believe the subtle differences end up being audible due to the degree of amplification. But in the grand scheme of things, this is just a part of the entire signal chain that can effect your sound.

share|improve this answer
And +1 to you - it's critical to examine/consider the instrument as a whole. – overslacked May 20 '11 at 19:57
Thank you for the help! – user4345 May 20 '11 at 20:16

One of the major ways the vibrations can affect the sound of the guitar is by allowing greater feedback influence (most especially with hollow-body electric guitars). Example, Trey Anastasio has several extremely resonant guitars, and that controlled feedback is a signature of his sound.

As for actual EM influence in this case, there isn't any; but that doesn't mean the body of the guitar can't have a tremendous effect on the guitar's sound and playability.

share|improve this answer
Thanks for the feedback, hah! I love Phish. I understand that hollow-body electrics are more resonant, but still not getting the part where these vibrations are being transferred electronically – user4345 May 20 '11 at 19:50
@Big Map Ideas, @Jon's answer addresses this directly (the transfer is the physical movement of the pickup in relation to the string, as well as the string itself moving in response to being struck/resonating). – overslacked May 20 '11 at 19:56

Of course it does not affect the "sound of the pickups", but the pickups don't have any sound to themselves anyway: they only pick up the sound that's coming from the guitar strings and modify it.

The sound of the strings, on the other hand, is affected quite a lot by the mechanical resonances of the guitar, in particular by the neck but also by the body. Because on a frequency the guitar can easily resonate to, the strings are able to release much more energy into the environment than for a frequency where the body does not move along at all. And which frequencies these are depends on a lot of parameters, which are different for every guitar type and even for guitars built in exactly the same way but from different types of wood.

So if you equip, for instance, a Les Paul and a tele with exactly the same pickups an circuitry, you will still get very notably different sounds. The difference is even more obvious when you also consider hollow-body guitars: quite a lot of these actually do have the same pickups and circuitry on them as Les Pauls, but still sound completely different.


To make the point about the mechanical resonances a little clear: if you built a guitar by spanning one string across a plastic broomstick, no matter what pickup you equip it with, it will always sound like just what it is. That's because the material is so light and soft that it can resonate to virtually any frequency and absorb a lot of energy.

On the other hand, if you use a massive block of granite, which is so heavy and hard that it will resonate but very little, you get a very long sustain (most damping is then due to string stiffness and perhaps even air friction) and a literally very hard sound, because none of the overtones are filtered particularly strong.

share|improve this answer
Thank you for the help! – user4345 May 20 '11 at 20:16
1  
"but the pickups don't have any sound to themselves anyway" Disagreed. Resonances in the coil, the type of magnet you use and how worn out the magnet is can have an effect on the sound. – nitro2k01 May 21 '11 at 6:28
I didn't say the pickups don't affect the sound - of course they do, very much so. The point is that they don't produce it, in particular they have, unlike the neck and body, neglectable influence back on the original string vibration. So speaking of a pickup's sound in relation to a guitar's is little more then relating a microphone's sound to a singer's, though microphones usually vary much less in their characteristics than guitar pickups do. – leftaroundabout May 21 '11 at 12:41

Wood Is Not Magnetic. The only thing that matters is what the string comes in contact with, the bridge, the nut, the tuners, a guitar pick, and the player playing, as long as the hardware and electronics are exactly the same, the wood will have no bearing on the sound as perceived by an electro magnetic guitar pickup, they are not microphones and wood is not magnetic, END OF STORY !!!!

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.