Rhythmic music - 2 - Performance and expression

Various practical aspects of performing rhythm, its performance and related intricacies in different musical styles of the world. 

This is the second of a 2 part post on rhythm in music, please see the first part here.

I am interested in music and dance in general, and while enjoying various styles of these, I also find basic similarities between them to be very beautiful. I will also share some things that I personally like and find interesting in certain styles of music, and discuss my aesthetic preferences in general.

Performing and indicating rhythm, articulation and dynamics 

An important question would be, how is rhythm performed and indicated, so that it is actually heard? We will first look at what can be used to perform rhythm. For an instrument to perform rhythm, as mentioned before, it should be able to discretely change sounds at desired speeds, and exactly at the required times, without sliding smoothly between sounds, since that will not give clarity of when each sound appears. 

But the more distinctive feature required in a rhythmic instrument, is to make a percussive sound, which is what will truly give a clear rhythmic sense and clearly mark times in a rhythmic pattern. This property of having a percussive sound is dependent on both the intrinsic sound quality, or timbre of an instrument, and the way an instrument is played. The particular characteristic of an instrument's timbre related to this is its attacking time, or the time when the sound, once played, reaches its maximum amplitude or volume. 

A sound has an envelope, which indicates the change in the amplitude/volume of sound from the time it first appears to the time it fades away. This is called its ADSR envelope, indicating the times of attack (when the sound first reaches maximum amplitude), decay (when the sound goes on to reach a stable amplitude/volume), sustain (when the sound stays at an amplitude/volume for some time) and release (time taken for the sound to fade away). 

Having a fast or instantaneous attack time means that the maximum amplitude/volume of the sound is heard almost immediately after playing an instrument, so the sound is sharp with almost no lag between the time of playing and the time the sound rings in the listener's ear. Instruments with percussive sounds can make sounds that have an almost instant attack time and fade away in whatever amount of time (this varies by instrument). 

In short, all the instruments that can possibly be used to play rhythmic music are -  

• drums, 
• cymbals, 
• clappers and castanets, 
• jaw's harps, 
• musical bows/monochord broadly pitched strings, 
• jingles and bells, 
• shakers, 
• scrapers, 
• tappers, 
• gongs, 
• woodblocks, 
• slit drums, 
• vocal percussion, 
• keyboards, 
• sharply pitched gongs, 
• handpans and other sharply pitched solids, 
• struck zithers/hammered dulcimers, 
• harps/lyres, 
• most plucked and strummed string instruments (zithers and lutes), 
• bowed string instruments and hurdy gurdies, 
• mouth organs,
• and brass wind instruments. 

The usage of these to play rhythmic music depends not only on their percussive sound, but also whether they are actually used to make such sounds in the styles of music that use them.

All percussion instruments, or instruments played by striking, shaking or scraping in someway, and struck and some plucked and strummed string instruments, have a sharply decreasing ADSR envelope, which means they have fast attacking time and decay not very long after, because of the way they are played, so these are some of the instruments used to play rhythmic music. 

The instruments which are tuned to sounds with pitches having specific relations (this will be explained more in another post), sharply pitched instruments (mostly the keyboards and others mentioned after it in the above list, and less commonly, some drums), are generally made with a longer sustain so that their pitch is clearly heard. 

The others are made to sound sounds with pitches that vary more broadly, broadly pitched instruments, and these don't aim to project specific pitch relations, they are almost always used only in rhythmic music. Vocal percussion has sounds made by the human mouth and its parts, and mostly uses consonants to give percussive sounds. Among the sharply pitched instruments, keyboards, sharply pitched gongs, handpans and other sharply pitched solids, struck zithers and most harps/lyres have a somewhat short decay (but some devices may be used to sustain sound, like pedals), while accordions are different since they can sustain pitch, but all of them change sound discretely and always make percussive sounds, so they are also used about exclusively in rhythmic music. 

Plucked and strummed zithers and lutes and some harps/lyres are also often used to play rhythmic music, but this may not be exclusive, and depends much on the musical style. In particular, they are sometimes used to play music which may not be rhythmic as we have defined, especially in various regions of Asia. Mouth organs and harmonicas also change sound in a mostly discrete way because of the playing needed to make sound and are used mostly in rhythmic music, seldom being used for other music. Hurdy gurdies have rubbing just like plucking or strumming, with keys, so they produce mostly separate strokes and rhythmic music.

Bowed string instruments, brass wind instruments and harmonicas can change sound both discretely as well as continuously/smoothly, hence they can be possibly used to play both rhythmic and other music, but because of percussive action typically include rhythmic components. Bowed string instruments  have bowing or rubbing just like plucking or strumming, so these can be used to perfectly play rhythm by bowing without delay, and it is bowing, that is completely controlled by the player, and can be equally rapid or gradual, that this depends on. But since bowing can be used to give both discrete and continuous sounds, they are generally used to play music that is either rhythmic or combining both effects, or more rarely, some purely melodic music, but this usage depends mostly on the style of music they are used in. Broadly, European, American (North, Central and South), Oceanian, North and Central Asian, East Asian (both Northeast and Southeast), West Asian and African musical styles use bowed string instruments to play rhythmic music including some mixed effects. Many styles of South Asian music don't use bowed string instruments as truly rhythmic instruments but rather as more continuous and smooth sounding instruments, and bowing instead mostly helps to separate musical phrases and so on, giving mostly purely melodic music.

Brass wind instruments may be sharply pitched or almost monotonic (with broadly varying pitch that may not be controllable by the way it is played). Sharply pitched brass instruments are found mostly in Western regions of the world (Europe, Americas and Oceania) and many regions of the African continent, and sometimes in other regions of the world in styles influenced by these regions. To play different sounds (in this case of different pitches), the lips have to be moved to vibrate and change pitch, and other handles (valves, slides, etc.) may be used to change the lengths of pipes to change pitch even more. So the playing style naturally makes more percussive sounds which may often also change discretely, but is directly controlled by the player, and sharply pitched brass instruments are often to play rhythmic music because of this although more rarely, they may be other music. Other brass instruments have naturally changing sounds that cannot be controlled so directly and may vary broadly, and may sometimes be used to play some rhythmic music or even give a constant pitch for reference. 

The instruments not included earlier are, woodwind instruments (flutes, panpipes, ocarinas, reed pipes/oboes, clarinets, etc., and bagpipes) and the singing human voice. These instruments, although they may be used to make sharp, discrete sounds even though they are naturally suited to make continuous, smooth sounds, but still don't have a percussive sound quality because of slower attack time. So they cannot be depended on to give a clear sense of rhythm, and are used for music other than rhythmic music. 

Only music that satisfies these conditions of actually having an intended rhythmic structure, played on a percussive or rhythmic instrument which is, most importantly, actually used in such a rhythmic way, is rhythmic music. Rhythm may be implied but not actually performed or expressed, but that will not make rhythmic music but rather only music in rhythm. Some layers in a musical piece may be rhythmic while others may not be. This is how I call a musical piece rhythmic.

Now we will look at how the rhythmic structure and the time signature of a musical piece are performed so that the listener can detect them. To indicate a time signature, the basic way is to indicate the first beat of a bar. This is done by playing either playing the time signature's metre (regular beats) directly or something close to it, using sounds that are grouped in the time signature's metre. The first beat can be indicated by playing a sound that stands out from the others. This can be done in many different ways.

The same idea can be used to mark the small groups of rhythmic patterns, or rhythmic cells/motifs and the phrases that are formed by combining these. The ways that can be used to contrast sounds at such places include:

1. Changing dynamics or loudness - A sound can be made distinct by playing it louder than the sounds around them, and this is an accented sound, and other sounds are then unaccented

2. Using a combined or heavy sound - More than one sound simultaneously played or some kind of a heavier sound could be used as compared to the sounds around it.

3. Changing articulation, sound length and appearance - Articulation is actually the way a sound is played, and in this context it refers to how much or for how long the sound resonates. A distinct sound may be made to resonate longer than the sounds near it, and it will be a legato or resonant sound, while the others may have a staccato or non resonant sound. In general, sounds of longer length can also be distinguished among sounds of shorter length. Sounds appearing after a silence can also be recognised clearly, and so silences could also divide groups of sounds.

4. Using a low or shifted sound - If a sound has a lower pitch moving away from sounds around it, it will appear distinct, and this can also be done by shifting the pitch levels of sounds (or simultaneously played groups of sounds) in a bar.

Any of these ways can be used to express distinct patterns, clear structures and the movements of rhythm in music.

This is all the general information on rhythm in my view, and I have also tried to briefly indicate the variety of ways to use and perform rhythm as seen in musical styles around the world.