How many kinds of pick-ups are there?

[Steven Tari]

I know of Four different kinds. One was the small Micro type in Acoustic guitars. The other is the kind in acoustic guitars that fit in the Sound hole. The third is the regular kind on Electric guitars that are mounted on the front and the last is like on the jazz guitar mounted on the neck. What other kinds are there?

[martinh]

In physics terms, I can think of three general categories (1) Microphonic pickups that use some sort of diaphram to pick up variations in air pressure caused by sound waves and convert it to an electrical signal, (2) Contact pickups that directely translate physical vibration into electrical signals without it passing though the air first (such as pizeo bridge sensors and old-fashioned "contact mics") and convert it to an electrical signal, and (3) magnetic pickups that do not rely on either sound tranmitted though air, or direct contract with a vibrating source, but pick up the distubance in a magenetic field caused by a magemetic string moving within the field, and convert it to an electrical signal,

 

I think that all common pickup systems work on one or more of these principles.

[milod]

Martin should ought to be close enough for folk music.

 

I think Shadow claims it's little nanomag pickup does about a combination of magnetic and "piezo," but... functionally it's a radical variation of the magnetic pickup.

 

From Shadow's web site, the clincher is: "NanoMAG combines various, high-quality Samarium Cobalt magnets with an air coil and active electronics..."

 

The magnetic pickups in an acoustic's sound hole are similar in function to other "electric guitar" magnetic pickups. As Martin noted, they are wrapped magnets that respond mostly to the changes that iron/steel strings make in the magnetic field when they vibrate. That's why they don't work on nylon-strung classical guitars and don't work that well even with bronze-wrapped steel strings compared to "regular" steel strings.

 

The various piezo and "contact microphone" sorts of pickups are siblings of the "real" microphone in that they all directly change vibrations in wood or air into an electric signal to pass onto an amplifier. Frankly I class them all the same from the perspective of the mechanics of turning sound vibrations into electrical energy, although they may differ radically in specific technology.

 

An engineer could put it into a lot fancier words, but I think that covers it.

 

The bridge piezos like on the Variax and such instruments is really nothing more than one piezo per string that's then handled differently in software. For example, if you want the piece to sound like a 12-string, you can use software octaving on the lower four strings, and just some chorus on the top two strings. That separation of strings for software purposes is why 12-string emulation with just a magnetic or just an overall "piezo" just doesn't work that well at all.

 

m