Some pickup theory please

[rbkxiiowe]

I understand that when a guitar string moves in the magnetic field of a pickup it induces an AC voltage in the coil, which oscillates according to the direction of movement of the string. But if I was to pluck two strings and they happened to vibrate like a mirror image of each other, wouldn't their induced voltages cancel each other out? Does something like this happen every time you strum a guitar where parts of the signal are canceled out and others reinforced?

I'm not great on this stuff, but I hope you see what I'm trying to ask

[kuzi16]

short answer. yes. the strings act as waves and do cancel eachother out a bit but they have to be EXACTLY the opposite of eachother to actually cancel eachother out. <br><br>this is why an oop sound is so cool. its kind of hollow and thin in a good way. the closer in design the two pickups are to each other the more sound you "lose". different bombos cancel out different frequencies.

[rbkxiiowe]

Thanks. So I suppose when only one string is plucked you're getting the full available voltage, but as soon as you pluck another one at the same time you start to mess with the first one's output, either canceling it a bit or reinforcing it a bit.

[ashcatlt]

While it may be theoretically possible, I don't believe there is any practical way to play two strings on a guitar and get nothing out of the pickup.

For starters, the strings would have to be identical in every way, including vibrating length, density, tuning, etc, and would have to be excited in exactly opposite directions on both axes (that's plural of axis, not a colloquial term for guitar).

In most cases, even when playing the same note on two adjacent strings there won't be enough frequency content that correlates to get any meaningful phase cancellation.

[pete12345]

when you play a string, you don't just get the fundamental frequency. There will be various harmonics mixed in with it, which is why the same note will sound different on two different strings. Playing more than one string will cause some interference- some will constructively 'add' while others destructively 'cancel' each other. Because you have so many different harmonics in there, you will never get silence from playing the same note on two strings

With pickups out of phase, the constructive interference becomes destructive and vice versa, so the fundamental frequency and some harmonics are almost totally cancelled, so you hear more of the higher harmonics, giving you that squawky sort of sound.

Pete

[ChrisK]

www.buildyourguitar.com/resources/lemme/