Is there a significant difference in how pickups are placed on electric guitars & basses?
On guitars I’ve seen them at the base of the neck, next to the bridge, and somewhere in between. Some are perpendicular to the strings, while some are angled. On basses, I’ve seen where they are split, but perpendicular to the strings.
How multiple pickups? I’ve seen some guitars with 4 or 5 pickups all closely spaced.
So what’s the dope on pickups?
The pickup makes a huge difference in sound depending on where it is placed. Closer to the bridge you get a much “brighter” sound (more high frequencies), and closer to the middle you get much more of a mellow sound. Angled or split pickups are giving you a mix, usually emphasizing the high end for the higher pitch strings and the low end for the lower pitch strings. Personally I think guitars with 5 pickups are overkill.
They would make a difference in signal amplitude, too. I have a tough time with pickup options in my electric mandolins, because there is much less room 'twixt neck and bridge, and smaller string excursion envelopes. It’s not geographically a long way from small, tinny signal to large, overly round signal. And harder to get two pickups in there.
You should check out the musical instrumant maker’s forum. Here’s a thread on pickup placement (there will be more in the library):
Linky
My other favourite message board. Lots of good folks, and levels ranging from complete tyro to world class professional.
Interesting. I’ll dig deeper.
engineer_comp_geek hit on everything technical I have to say. From a usage perspective, a typical electric guitar will have seperate volume and tone controls for each of the pickups, and a switch that picks between one, the other, or both combined (I can’t recall if they’re linked serially or in parallel). Often, the one closest to the bridge is used for a “lead” sound, as it’s brighter and more biting. The other is typically used for a mellower rhythm sound. There are plenty of exceptions, of course.
On guitars with four or more pickups placed closely together, would there be any feedback problems?
Also, is there any difference in pickups where the magnets are exposed as opposed to being covered?
Pickups are passive so the only thing affecting feedback is the proximity and volume of the amplifier and the guitar body’s ability to resonate (an accoustic/electric guitar will feedback far more easily than a solid body electric).
The difference in sound with pickup position can easily be approximated by taking an accoustic guitar and picking at different positions along the neck. Close to the middle is mellow, closer to the bridge (or head) gives a twangy, bright, cutting sound.
I can’t remember if there is much difference in sound with a covered pickup, I should know as my guitar has both covered and uncovered pickups. Sometimes pickups are dunked in wax which is supposed to reduce feedback.
What everyone else says…and…
Four or more pickups is probably a gag*. I’ve seen a Les Paul with four pickups crammed in but that’s just stupid.
In case you don’t know… There are two basic types of pickups, single-coils, and twin-coil-humbuckers. Usually a humbucker has the coils side by side but they can be stacked up. You get more high harmonics (twang) out of single coils and more power from humbuckers.
As well as the pickup’s position it can be wired up to switch between single/double coils (coil tap), to change their phase relative to other pickups, change coils from parallel to series winding, and probably other stuff too. All of which effect the sound.
BTW I have seen a guitar with a single pickup on a slide so you can move it up and down, a Dan Armstrong(erm?) looked a bit impracticle.
You do also get weirdness like three coil pickups and ones with separate coils for each string but they’re pretty rare.
*Nigel Tufnel has one. It has a speedometer too.
The key is that the pickup is “picking up” the vibrations of the string. Strings vibrate different ways along their length, so placing a pickup at different points along the length yields different sounds.
Multiple pickups do have their uses. There are a few reasons one might wish to use more than one pickup:[/list][]To provide an even detection for all the string harmonics, since some of them will have nodes at the pickup position and thus contribute less to the signal.[] To cancel (“buck”) the noise (“hum”) associated with single coils (hence “humbucker”). To add two signals from different parts of the string providing a pleasant tone for eg. funk chords.[/list]Multiple pickups a la Spinal Tap simply provide more options in this respect, but as far as I know Nigel only ever uses the bridge humbucker!
A minor note (ha!): pickups can be wired together out-of-phase for some interesting effects, with certain harmonics cancelling each other out, etc. I think Brian May, guitarist for Queen, has a custom-built guitar where each of the pickups has its own phasing switch and other neat stuff (he and his father built the guitar together, if I remember correctly).
Incidentally, I only ever use the humbucker near the bridge for 95% of anything I play. It gives me lots of signal and some seriously bad-ass tones.
Re: feedback–Ted Nugent type is based on the string/body resonating with the sound coming out of the speakers. Squealing type comes from some of the wires in the pickup itself resonating; that’s nasty. That’s when you dip the pickup in wax.
Re: Humbuckers–there are two sets of coils, wired out-of-phase with each other. This gives the pickup more power and cuts down on hum (electromagnetic noise being received by the coils) but also tends to cut the highs.
It is common on Strats (which have 3 single-coil pickups, usually) now to have a 5-position switch, which gives 1) neck pickup, 2) neck + middle, 3) middle, 4) middle + bridge and 5) bridge only. On some of the Shecter Strats, you get a little 3-position mini-switch for each pickup: on, off, out-of-phase.
The options on Bass pickups are typically fewer–most bass players just pick a sound and stick with it. My (then) bass player had one of those slide-the-pickup-to-change-the-sound instruments. He never moved the pickup.
The Dan Armstrong guitar that I remember (the clear plastic one) had a pickup that you could replace–you removed a set screw and the darn thing slid out and then you slid in a different one IIRC. Obviously only useful in a studio setting. The thing was as heavy as sin as well.
I always wondered how he got that sound. It’s instantly recognizable.
For those who are interested, here are Brian May type guitar wiring diagrams: