String Portamento Tutorial
by Jim Walraven
The following tutorial examines playing portamento on stringed instruments. Although quite detailed, hopefully it will be an aid to gaining a better understanding about the mechanics of stringed instruments.
Playing portamento on stringed instruments is the subject of this tutorial, with the expressed goal of helping keyboard performers, composers, and others to better understand where and why slides and portamento effects occur. By grasping the basics of string portamento, more musically convincing simulations may be achieved. Most of this tutorial will delve into the exciting subject of string mechanics – a subject perhaps suited for the temporary cure of insomnia – but a subject at the very core of producing an effective emulation. As each section of the tutorial is clearly marked, it is possible to read the concluding recommendations first, and then go back to read about the mechanics if so desired.
Within the tutorial, the terms slide and portamento will be used somewhat interchangeably. The primary intent will be to explain where and why slides, or portamento, naturally happen during the playing of a stringed instrument. Due to string playing mechanics, there are situations where a slide will almost always naturally occur, conversely, there are many other circumstances where a slide will almost never happen. We will start by examining left-hand fingering technique, right-hand bowing practices, and how the two hands work in coordination. Next, the ways in which fingering patterns impact the resulting sound of the slide or portamento effect will be examined. Only after the technical issues have been thoroughly reviewed will a general discussion of portamento follow.
Left-hand fingering techniques.
Left-hand fingering techniques exert considerable influence on when and where a slide or portamento effect will or will not occur. Bowing technique.
First, it is important to recall the physics of a string. For each successive octave within the harmonic series, the distance between the octave harmonics is cut in half. For example, on my own bass, the distance between the pitch of an open string and the first octave harmonic is about twenty inches, while the distance between the first octave harmonic and the second octave harmonic is (surprise!) about ten inches. On a cello the corresponding distances are roughly 13 1/2 and 6 3/4 inches, and for a violin about 6 1/4 and 3 1/8 inches. Although no two instruments have precisely identical string or fingerboard lengths, the total available fingered pitches, excluding harmonics, for any string within any particular string family is roughly around two octaves plus about a perfect fourth (the highest available fingered pitches on the lowest strings are not normally used).
What difference does this make, you may ask (I hear the snoring already)? The physics of a string matters greatly, since as the physical pitch of each successive note, as in a scale, rises, the distance between the adjacent notes of the scale decrease. For example, in first position on a bass, the notes are spaced so far apart that each left-hand position can encompass only a major second (between the first and fourth finger). About an octave higher in beginning thumb position (the thumb rests on the octave harmonic), it is possible to play a perfect fourth (between the thumb and third finger). Even before reaching the octave harmonic the notes available within any one position may increase. On a cello, the range available between the first and fourth fingers in first position is only a minor third. When a cellist plays notes in sixth position, instead of each finger playing notes only a half-step apart, each finger may play notes a whole step apart (the fourth finger is not used on either the cello or bass starting with the sixth position).
So what (I hear the snores growing louder)? Whenever a string player is playing notes within one single position, the left hand will not move, and no slide or portamento effect will result. Since the left hand encompasses a wider interval in the higher positions, less shifting is often necessary when playing a passage in a higher position than when a similar passage is played in a lower position. As the passage in the upper register requires fewer shifts, there would be fewer places where a given technique might produce a slide – of particular importance when considering emulating solo string playing.
Basic left-hand technique is an equally important concern when considering slides and portamento effects. It is vital to remember that whenever a string player is playing successive notes on any one particular string, the player will keep the string stopped against the fingerboard, even during shifting. There are three primary circumstances when a player will cease to press a string against the fingerboard with the left hand. These circumstances are: 1) lifting the hand off the string to move it to a different string; 2) lifting the hand off the string in order to play an open string; and 3) playing natural harmonics, as natural harmonics are performed by lightly touching a node point on the string.
In each of these three situations, there will be no slide or portamento effect, as the hand will not slide up or down a depressed string in order to play an open string, a note on a different string lying in the same position, or a natural harmonic. In addition, it is unlikely that a portamento or a slide will occur on a note that follows either an open string, or a natural harmonic for the exact same reason.
It is possible that the player may need to slide the hand a bit to reach a note when crossing strings, if the new note is not in the same hand position as the previous note. If the next note is across several strings, and/or in a much higher or lower position, the player will place the finger down as close to the new note as possible. The total length of any residual slide will be greatly reduced in these two cases, compared to playing the two notes on the same string.
Since a player otherwise keeps the string depressed against the fingerboard, even when shifting, brief slides will often naturally occur where a casual observer would not expect, depending on the bowing that is being utilized (see below). Although an exaggerated portamento effect perhaps is most commonly requested when pitches rise, naturally produced slides or portamento are just as likely to drop in pitch as well as rise, since a player needs to shift down to lower positions every bit as much as shifting to higher ones.
At this point in the discussion, a few general remarks about basic bowing techniques are appropriate. Although it may seem obvious, there are a variety of bowing techniques that are not conducive to producing slides or portamento. Any short bow stroke – for example spiccato – containing space between subsequent notes rule out slides or portamento. Similarly, playing notes with successive down-bow strokes would normally eliminate the possibility of a slide, as time elapses between the end of the first down bow stroke and the start of the second stroke, as the player takes the bow off the string in order to reset it. When using short bow techniques, even if the passage consists of notes played on just one string, any shifting will normally take place and be completed before the string begins to vibrate sounding the next note. Left-hand and right-hand coordination.
One of the major challenges faced by beginning and intermediate string players is learning to coordinate the shifting that is done with the left hand with the bow strokes produced by the right hand. During the learning process, the player will produce many inadvertent and undesirable portamento or slide effects. These slides occur when the coordination between the two hands is faulty. Naturally occurring slides.
At the start of each bow stroke, it takes a small fraction of a second before the string begins to vibrate in response to the movement of the bow (this moment is especially pronounced with hard bow attacks). An advanced player will normally execute shifts during that fraction of a second. The player will either finish, or nearly finish, any necessary shifting before the new note starts to sound. Thus, usually a listener will here no slide or portamento effect at all, or if the required shift covers a large physical distance, perhaps only a very tiny slide over the final small portion of the shift.
When the two hands are not well coordinated, and especially if the player is either consciously (or unconsciously) afraid of not being able to complete the required shift to the next note in time, the player will start the shift before completing the current bow stroke. My bass professor, albeit many years ago, referred to this shortcoming as “shifting on the old bow.” The faulty hand coordination produces a very noticeable slide, since the string is still sounding as the player starts to move the left hand. To the listener, the result sounds like very sloppy playing, even though the actual notes may be well in tune (the undesired slide may well serve as a crutch to a beginning player struggling with intonation problems).
Thus, for an experienced string player, slides will therefore not occur, be nearly inaudible, or greatly reduced, when a shift in the left hand occurs at the same time with a change in the bow direction in the right hand. Even if the interval between the two notes is quite large, a slide will at most be minimally evident, and even then, only in a range close to the pitch of the new note (either up or down).
Having discussed left-hand mechanics, bowing methods, and the coordination between the left and right hands where slides generally do not occur, it is important to consider one particular bowing technique where slides naturally will occur. Fingering the portamento or slide.
When a series of notes are fingered on one string and are slurred together within one bow stroke, a slide will result whenever the left hand shifts position. Why? As discussed above, a player will keep a string pressed against the fingerboard as long as notes are being performed on that one particular string. In addition, when slurring a series of notes within a single bow stroke, the bow will not stop moving at any point while the series of slurred notes is being played. Thus, when the player shifts position, the string remains pressed, and the bow continues to move during the execution of the shift. The movement of the left hand up or down the string while the bow is moving produces the slide. Depending on the distance of the shift, the slide might be fairly long, though it also could be quite short. Within a slurred passage, a slide with an interval as small as a second or third is very possible.
Someone might think that the resulting slide is somehow undesirable, and that it could perhaps be avoided if the player simply lifted the hand off the fingerboard while shifting during slurs. In actuality, doing so would produce several undesirable effects. If the player took the hand completely off the string while shifting, the note of the open string would sound, since the bow would still be moving. If the player tried to shift while lightly touching the string, but not pressing it against the fingerboard, hideous squawks and squeaks would result.
The slides produced when shifting while slurring notes on one string are a natural part of legato string playing. It is therefore not surprising that slide or portamento effects occur most frequently during the playing of legato passages.
Nonetheless, there is one common technique where leaps within a slurred passage will not produce a slide – when slurred notes are performed across different strings. When playing legato passages across different strings, the player may well be able to finger the two notes without shifting, and may even finger the two notes simultaneously to make the slur even smoother. If the string crossing does require a shift, the resulting slide will likely be very small, sounding close to the new pitch.
When studying a piece, the player will decide how it should be interpreted, and what fingerings to use. The player will choose when to play legato passages on one string, and when to play legato passages across different strings. Sometimes a legato passage must be played across the strings, as when a needed otherwise isolated lower note is only playable on a different string, or if the passage contains many successive leaps. The player’s fingering and bowing choices will determine where slides will naturally occur in the performance of the piece. Indeed, the player will deliberately make these choices based on his or her intended interpretation of the piece.
It is often desirable to play legato passages on one string. Since each string has its own unique timbre, the most seamless legato within a phrase is maintained by playing the entire phrase on one string. As previously stated, slides or portamento are most common when fingering a passage on a single string.
Before moving on to a general discussion of portamento, the impact of left hand fingering on the actual sound of a portamento effect must be analyzed. The fingering technique a player decides to use directly impacts the resulting sound of the slide.
In many, if not a majority of situations, the finger used to play the starting note of a portamento will be different from the finger used to play the ending note. Especially when the slide encompasses a wide range of notes, with the destination note performed in a much higher position, different fingers might be used. Portamento.
A player will generally not keep three or four fingers pressed against the fingerboard while executing the entire slide, as doing so could result in an awkward and cumbersome shift. If the entire length of the portamento is played using only the first finger, but the actual final note is played with a different finger, a gap will exist between where the player ends the slide and the sound of the actual ending note. The player will end the slide with the first finger relatively close to its correct location in the new hand position, and then play the actual note with the other finger.
A method exists to produce a smoother slide, and is the one I personally prefer, when using different fingers on the starting and ending notes. By changing the fingering during the execution of the slide itself, the effect may continue all the way through to the destination note. Doing so has almost no effect on the sound of the actual slide – the listener will still hear a continuous slide. By using this technique any gap in pitch between the end of the portamento slide and the final destination note is effectively eliminated. It is true that the player may overshoot or miss the destination note by a small fraction and have to adjust accordingly, but small adjustments are often required after any shift, and are by no means restricted to producing portamento.
Having reviewed the circumstances where slides naturally will or will not occur, and discussed the impact of fingering on the slide or portamento itself, we will now turn to a general discussion about the use of portamento.
It has been the goal of this tutorial to provide insight into the mechanics of playing portamento on a stringed instrument, to help non-string players think about performing it as an actual violinist, violist, cellist, or bassist might think. As understanding is gained about producing an effect on a particular instrument, or family of instruments, the more convincing and realistic the emulation of that effect may become.
In this final section of the tutorial, common mistakes in the use of portamento will first be examined. The section will conclude with some general suggestions for its effective placement.
In listening to a number of demos, while the use of portamento was well intended, the resulting effect often did not succeed. When a player chooses to add a slide, or portamento, it is added with the intent of aiding the interpretation of the piece and evoking the mood that the performer wishes to convey. Too often in the demos, the placement of the effect drew attention to the isolated effect itself, rather than aiding in the interpretation of a particular phrase. The result detracts from the intended simulation of a real performance, since a performer is (usually) not seeking to have the audience focus on a particular effect.
The difficulty is further compounded when the effect itself is executed in a way that sounds unnatural. Two related weaknesses were particularly evident. First, and most important, the portamento was often extended over too long a period of time. Unless a composer specifically requests it, a string player simply will not normally take an entire second, let alone even longer, to shift between positions (though there are exceptions). The slide simply will not last as long as it does in some of the simulations.
Second, and closely related to the first weakness, the shorter the distance of the shift, the shorter the duration of the portamento. To insert a portamento effect that lasts nearly a second when the distance between the two notes is relatively small sounds especially unnatural. As discussed above under playing techniques, a slide may naturally occur between notes that are quite close together, but it will be very brief in duration. On the other hand, if the distance between the two notes is quite large, the portamento effect will last considerably longer. As the distance covered by a shift increases, the time required to complete it will also increase. The same portamento effect that lasts far too long and sounds very unnatural when the two notes form a relatively close interval may be very effective when the interval distance between them is far greater. Seek to match the total time of the portamento with the time it would take for a player to execute the shift within the context of the passage itself. It is important to remember that notes further up the fingerboard are much closer together than notes played in first position.
When thinking about inserting a slide or portamento into a sequence of a piece, it is helpful to think about how a string player might interpret the piece. When considering the bowing techniques used for a particular passage, along with the related left-hand mechanics, ask yourself if a performer would add portamento at the point being considered. Especially if the required playing techniques at that moment preclude the likelihood of a portamento effect, do not insert one.
A player actually has great flexibility in terms of when to insert and when not to insert portamento. Earlier in the tutorial the coordination between the left and right hand was examined, and reasons given why slides do not normally result when a player shifts when changing bow directions. Yet, a player could choose to deliberately add portamento at that point, if the player felt that doing so would aid in the interpretation of the piece.
Inserting portamento may be most effective when simulating slurred legato passages intended to be played on one string. As discussed, within any slurred passage, a naturally occurring slide is as likely to go down in pitch as up, though including a full portamento rising up to a very high note may be particularly effective – though if done inappropriately it could just as easily detract. A portamento effect need not be limited solely to legato passages. A player could possibly decide, if it was felt appropriate, to include portamento when shifting between two longer notes that occur within an otherwise quite rapid passage.
Slides or portamento are best incorporated into an interpretation where they would naturally fall. An exaggerated slide or portamento, especially if placed where it would not normally happen, serves more to draw attention to the effect itself or simulate sloppy playing, as opposed to emulating an actual desired and well thought out interpretive effect. By keeping the mechanics of playing a stringed instrument in mind, by not inserting portamento where it would otherwise not occur, and by tailoring its length to correspond to how a player would actually perform it, a more realistic simulation of portamento may be achieved. It is crucial to remember, as the distance of the shift in the left hand changes, the corresponding amount of time that is required to execute the portamento also changes.