There are many choices in mandolin strings, and ultimately, a player will make a purchase decision based on tone considerations, finger feel and response, longevity. Personal experiences with even less measurability like string malfunction and breakage factor in; many players will completely write off a brand because of a few random incidents with a manufacturer's occasional blem. Although many like to experiment once in a while, most eventually settle in to a string that brings out the best in their own instrument, and creates a signature sound.

We were big on flatwound strings because of the smooth feel at first blush, but there are indeed tonal considerations which make a flatwound string ideal for jazz.

Brightness and the Overtone Series.
For the brass player, the overtone series actually makes up the entire range and sound of the instrument family (see What are harmonic overtones?), so the notion of open fifths and harmonics are very much second nature. Fretted string instruments have some experience playing harmonics on the 12th, 7th, and 5th frets, but not as much. It might be esoteric to dig too deeply into the exact structure; let's just say the timbre of the instrument is affected by how much the upper partials of a sound are emphasized.

A simple concrete example of this sound manipulation is as close as your mouth. Try singing a stable medium low pitch mouthing the syllable "Bah."

BAAHHHHHH. Sustain it five seconds or longer. Now do the same thing, same pitch but after 3 seconds, change the syllable to "Reeee."

BAAAHHHREEEEEEE. Don't change the pitch coming from your vocal chords. Notice how as your mouth changes, different tonal colors are emphasized. Even though the low fundamental pitch is the same, there's quite a difference in timbre. This can be experienced similarly on the mandolin when you move the picking area closer to the bridge or up to the fingerboard.

Roundwound strings give you more of the "Reee" sound. The word "complex" is bantered around to describe the tone, and with it, you get brightness, definition, and "edge." This is great for campfire picking, especially when competing for sound with a group of other acoustic instruments, and necessary for musical styles that use lots of open 5th drones. It projects better, and arguably makes the sound more interesting.

In jazz, we start introducing more complex pitch combinations with the higher chord extensions, like A13b9, D7#9, Bm9, or Eb7#11, and this brightness can create conflict and actually detract from the harmonic power of the chord. You want more fundamental ("BAH" sound) in the string. This is especially true when you amplify; the need for complicated tonal color and projection is simply not an issue.

Of course you have to factor in playing style, instrument construction, and pick structure as well, but in general, the purer fundamental produced in flatwound strings suit playing jazz very well.

Your results may vary.

Posted by Ted at August 28, 2008 6:13 AM