Density/Expansivity in Music

Sound can be dense or expansive, relatively speaking. In fact, any element of sound or of music can have its own density/expansivity attributes that contribute to the overall density/expansivity of a sound, of a piece or music, of an ensemble, or any element of music or sound. This will be referred to as the Density/Expansivity Factor or D-E Factor.

Every musical instrument has it’s own D-E make-up.  Mandolin is relatively expansive for a variety of reasons. But before we go into these characteristics particular to the mandolin, lets talk about the D-E Factor or D-E in general terms.

Density could be summed up as “stuff drawn together into close proximity”. A collection of “stuff” could be strewn across it’s measuring scale and therefore expanded, or particular elements of this “stuff” could be weeded out, also “expanding” its nature. It could be argued that the most expansive element of sound would be silence. While some may say that silence really has no aural or musical value, I disagree. You certainly have heard the expression, “Silence is louder than words” and composers, speakers, performers of all types who can master the use of silence greatly enhance the value of their expression.  In an active and crowded world, silence may be a rare commodity, practically non-existent, but nonetheless a valuable commodity, one worth considering.

Regarding sound, let us consider that density can be associated with a number of verbal descriptions: richness, clutter, thickness, denseness, complexity, and so on. Similarly, exansivity could be summed up as: thinness, purity, cleanliness, simplicity, lightness, and so on. These may not be the best choice of terms and may have positive or negative connotations, but nonetheless serve as examples.

The D-E Factor of an Individual Sound

If we study the harmonic series, we notice that the pitches that make up a musical tone are naturally spaced widely at the bottom and closer together at the top. Any sound we interpret as “pitch” is made up of a series of pitches: a fundamental along with its octave, a fifth above that, a fourth above that (making the second octave), a major third, a minor third, another minor third, a major second (the third octave), followed by a series of stepwise intervals.

The oboe has twice as many pitches (or “partials”) in its sound than does a clarinet.*  It is a brighter sound, yet it is more complex, more dense while not necessarily louder.

Not all sound characteristics of an instrument are related to the harmonic series.  An instrument’s typical sound envelope (attack/decay of a played note), extraneous sounds such as pick clicking, squeaking of fingers sliding across the strings, keys clattering, etc, even when masked by the player, have an effect on the density of the instrument’s sound. Similarly, the resonance of a sound box, the shape, size, thickness, and bracing of the soundboard, the size of the soundhole….too many factors to list here, affect the density or richness, the projection or penetration of an instrument’s sound. Such attributes affect the sound of an instrument standing alone and greatly affect how that instrument can add to the mix of an ensemble.

The Bardo of D-E, moving from the individual instrument to the ensemble

Now, we shall move from discussion of the individual instrument to how it relates to the rest of an ensemble. But before we do, another note on density and expansivity. Density may appear at this point to be the real element and expansivity might seem to be the lack of it. In ways this is true and in ways this is not. It should be considered that density has a tendency to reside in the instrument’s sound make up while expansivity has a tendency to reside in what is done with the instrument.  Please note the use of the term “tendency”, this is by no means absolute, but if we are to understand and use the potential of an instrument, considering this statement can be of practical use.

Contributing to the Ensemble

Let us take a moment to review how we have heard instruments used in ensembles and think about what each adds to the mix. Consider a traditional ensemble: flat-top guitar, 5-string banjo, fiddle, upright bass and mandolin. To make it simpler, lets remove some of the band members, just include guitar, fiddle and mandolin.  The role of the fiddle is primarily a lead role and focuses on melody. The role of guitar is supportive and offers rhythm and harmony.  Mandolin fits somewhere in between yet can add elements that are over and above each of its partners.  For instance, the sounding pitches of the mandolin are the same as the violin, yet the richness of the violin’s tone versus the percussiveness of the mandolin give the mandolin a feel of being a higher instrument. Compared to the guitar, the mandolin is surely less able to fill the sound of the ensemble yet in terms of both rhythm and harmony, it can add very strong punctuation, over and above that of the guitar. Bringing the banjo and bass back into the group, we could easily say that when considering density and expansivity, the bass and guitar are denser/richer, the fiddle is in the middle, and the mandolin and banjo are more expansive.  All the while, each instrument has elements of expansivity and density that contribute to the ensemble’s sound.

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* The oboe’s sound chamber, being conical and closed on one end, produces all the partials of the harmonic series and accentuates the upper partials to some degree making he sound brighter and more complex, similar to a “sawtooth” sound wave. The clarinet’s sound chamber, being cylindrical and closed on one end, produces only the odd numbered partials and attenuates the upper partials, giving it a purer sound, similar to a “square” sound wave.