Music: Practice & Theory Stack Exchange is a question and answer site for musicians, students, and enthusiasts. It only takes a minute to sign up.
Sign up to join this community
inspired by Are these double stops playable on violin? :
I have never had the opportunity to play a fretless string instrument. When writing music for violins or other string instruments, what rules can I follow to ensure that I don't write double stops that are impossible/impractical, whether in isolation or due to their relation to adjacent notes?
First, there are physically impossible double stops. The notes below the open next-to-lowest string can only be played on the lowest string, so you can't play two notes at a time in that range. For example, a low G-B double stop on violin would be impossible.
Next, understand how the instrument is tuned. Viola, violin, and cello are tuned in fifths, while the bass is tuned in fourths. This means that those intervals require zero reach, and as the interval grows or shrinks from there it requires the player to stretch further.
The limitation then comes from the scale of the instrument, and that the notes are furthest apart in the lowest positions (closest to the nut). On violin and viola, reaching up to an interval of a fourth (on one string) is basic technique in any position, meaning that double stops from a major second to an octave are natural. There are solo violin excerpts stretching up to a tenth, but that should be considered advanced.
On cello, as another commenter explained in more detail, the reach is more limited so you should stick to thirds and sixths more. The span involved in reaching minor or major sevenths is the same as for major or minor thirds (respectively), but the seventh is a dissonant interval so it's rarely seen. Seconds and octaves should be considered advanced.
On contrabass, the scale is so large that you can't reach very far at all. To give you an idea: on a 3/4 size bass I can barely span a whole step in first position, and I can easily reach a tenth on piano. Remembering that the strings are tuned in fourths, the limit for double stops in low positions is merely from thirds to fifths. Considering that small intervals sound muddy in the bass register, you should probably only ever write fifths, if even that.
When writing phrases containing consecutive double stops, it's always easiest when the span is comfortable and the notes move in parallel. For violins and violas, consecutive thirds and sixths (even mixing major/minor) are very common. Consecutive octaves are a bit more advanced but still considered standard. Of course, the other intervals are also possible but compositionally questionable. You won't see runs like this on cello as much, but consecutive sixths are very playable.
When writing phrases consisting of consecutive double stops of varying intervals, there are all sorts of pitfalls you can fall into, and it's hard to summarize them in a post like this. I might suggest that such writing is best left to advanced players of these instruments, or at least you should check the parts with a player rather than trying to apply some general rule.
I'll defer to others to answer for violin and viola.
Quite obviously, most double stops where one note is an open string are easy.
Apart from that, the safest double stops are generally major and minor sixths; you can use these in almost any context provided both individual notes are in the range of the cello – i.e. the lower note at least C2, the higher one at most ≈A5.
Fifths are extremely easy in the non-thumb positions (simply use a barré across two strings), though they are not always intonation-safe. In the higher positions (upper note >G4), fifths are actually quite tricky.
While relatively less interesting musically, tritones, fourths and minor sevenths are almost as easy to finger as the sixths and can be used in any position too. Fourths can be surprisingly hard to get the intonation right though.
Major thirds can usually be played ok, but may be difficult in some contexts. Minor thirds likewise, but always a bit more difficult because they require an extended position. Runs in thirds require a position shift at every note change, which makes them much more difficult than runs in sixths. Also note that the higher note in the double stop must be playable on the G-string, i.e. not lower than G2.
Octaves require an over-extended position unless the lower note is on an open string. Over-extended is doable, but hard for players with small hands. Octaves are significantly easier in high positions, specifically in thumb positions (lower note >C4).
In any case, intonation problems in octaves will be very obvious (both to the player and audience).
Seconds and Major sevenths are neither easy nor typically musically useful in the cello's register, so only use them if you really mean it.
Make certain they are not separated by more than EA,AD,GD.
