Why do flats sound flat and rounds, zingy?

[4 Strings]

Any ideas? Trapped air pockets?

The signal generated by the string and pickup is due to the steel cutting the magnetic flux. Its not microphonic.

And yet an amazingly varied tone can be achieved. Not just the profile of the windings, but if you physically dampen the string with your palm the expected acoustic sound is reproduced electronically. Somehow, instinct would tell you that it would. Even old or dirty strings you would expect to lose their zing acoustically. But why does it electronically? The string is still waving about, cutting the magnetic flux and generating a signal.

I suppose the difference in acoustic tone between flats and rounds is to do with aerodynamics. (Is it?) Why do they sound different acoustically? Why they sound different electronically I cannot fathom. More, why do half rounds (or ground wounds, pressure wounds etc) achieve what you expect, a half way house - electronically.

[Mr. Foxen]

The string motion produces the sound and the motion is a product of a bunch of factors, the simplification is in flexibility, the round windings damp the strings less than flat windings that are closer together. Really, for the purpose a pickup acts like a microphone, just instead of reacting to air disturbance from the string motion, it is reaction to magnetic field disturbance. Maybe picture a string of round beads vs a string of flat discs, if they are all packed tight, the round beads will tend to bend easier than the discs, that damps the higher frequencies.

[ikay]

It's an interesting point but essentially the string sound you hear with your ears is the same sound that is 'heard' by the pickup. Whether it sounds zingy or dull is all to do with the harmonic content being produced by the vibrating string. A new set of rounds for example will have lots of high harmonic content. If you damp these with your hand you will lose some of the higher harmonics. Similarly if you play nearer the bridge or over the neck the harmonic content changes. An old set of rounds will lose some of the high harmonics and sound deader. Flats have less high harmonic content than rounds and so on.

When the string wobbles back and forth through the magnetic flux, the signal generated by the pickup is a mix of all the harmonics being generated by the string [u]at the exact position directly over the pickup[/u]. This last bit is crucial. Pickups in different positions will 'hear' a different set of harmonics. If a pickup has more than one coil (eg. wide aperture humbucker) then each coil will hear slightly different harmonics. The different signals generated by each coil will interact and act as a filter with some harmonics being cancelled out and others accentuated. Similarly if the bass has more than one pickup. It's a complex cocktail of harmonic inputs and outputs!

This article on how pickups work explains it more clearly than I can - http://www.aqdi.com/pickups.htm

[4 Strings]

I suppose that nails it, the harmonics, thanks. Shows how much information the pickups are able to well, pick up, such subtle differences in wave form. We take for granted the quality of our ears.

It's still quite difficult to fully get my head around the many different frequencies being picked up from a single note, and how a pickup is able to pick up, convert an transmit these.

I suppose the next question would be [u]why[/u] round wound strings have more harmonics than flats.

[discreet]

Rounds are like springs. Flats are not!

[ikay]

Ref back to Mr Foxen's post, I found this:

"Roundwound strings are brighter, due to a higher presence of upper-order harmonics, while flatwounds are less bright. This occurs because roundwounds are more flexible than flatwounds.Imagine a string threaded with tightly packed beads. If the beads are spheres, then you'll be able to bend the string relatively freely; if, however, the beads are cubes, then the edges and corners of the cubes will inhibit the bending of the string. This same principle applies to roundwound vs. flatwound strings. When you pluck the string, it begins to vibrate, and as it vibrates, it flexes. Roundwound strings will have greater flex, while flatwounds will have less, because the flat windings inhibit the free vibration of the string. This suppresses the upper harmonics, causing flatwound strings to sound more mellow."

Which all rings true

Edited March 12, 2013 by ikay