sonic quality
The violin, viola and cello all have four strings.
from the lowest pitched string to the highest :
Violin : G D A E
Viola : C G D A
Cello : C G D A (octave below viola)
Think of the harmonic series produced by the fundamentals of the open strings and how they affect or excite one another.
Open strings always ring with more volume and amplitue or gain than do fingered or 'stopped' notes, much like acoustic guitars and other acoustic stringed instruments. Open strings will and do excite other open strings to a greater or lesser degree based on their fourth, fifth or octave relationship, their relative harmonic series as they occur in relation to the other open strings.
The same effects are true for fingered strings, (fingered thus a new fundamental and new harmonic series). Stopping a string, (fingering a string), creates a new fundamental with it's own harmonic series, and any fundamental will excite or cause sympathic ringing with other fundamentals whose harmonic series offer 'related harmonic nodes'.
The fundamental sonority, an open string perhaps, rings powerfully and richly, sounding all of its harmonics. The octave of the string rings bell like and pure with less gain but more pitch truth. When you create the harmonic an octave and a fifth above the fundamental, again, you lose gain, but the note becomes more pure, softer but sweeter, even more pitch true, more pure, (because there are fewer harmonics that belong to the fundamental series ringing within the produced sonority).
Any fingered note that is an octave or unison of an open string will certainly excite the open string and to varying degrees it's harmonics.
Example:
When I finger a D on the C string, the open D string an octave above will vibrate and ring quite vigorously even if I am not bowing it or plucking it also. Let's say for discussion's sake ... 1/5th the amplitude or gain of the fingered note. If the fingered note were no longer sounding, you certainly would be able to hear the open D string continue to ring 'sympathetically' as long as it is not brushed with a part of the fingering hand or a part of that hand thus 'stopping' that sympathy. Samples and electronica are always striving to reproduce these 'natural sonorities' as they might occur relative to the context of the production of the music.
Within the harmonic series of an open string you can produce an octave harmonic, (a light touch not fully stopping the string at the midpoint of the string), and this octave harmonic is the most powerfully resonating note in the harmonic series of the open string fundamental, (or stopped-fingered fundamental). The next in the harmonic series is the fifth above the octave, the next the fourth above the ocatve. I'm listing them in terms of amplitude, or gain if you will. The double ocatve harmonic loses even more strength, or gain, or amplitude, but will even more so produce that airy, pure and faery like sound.
Yes, we string players actually think about these things as we prepare to produce a note, or series of notes, sometimes making sure not to brush an open string with a finger or part of the hand while traversing on the neck, so that it can come into play sympathetically, lending it's harmonics to whatever sonority we wish to produce. Think 'feedback'. Or perhaps we purposefully will dampen an open string if we do not wish it's harmonic series to color whatever sonority we wish to produce.
This kind of thinking and playing is critical in the studio to producing a realistic and robust sound.
'Playing the fundamentals' and the harmonics they offer against or with one another, and using their harmonic relationships is very important in coloring the sonority you wish to produce. Being aware of the harmonic series of the note you are playing and how it relates to other fundamentals in use or nearby is very important.
Examples :
On Viola, playing the open C string and double stopping that sonority with an octave above, (by fingering a perfect fourth above the adjacent G string, --> C an octave above the open C string <-- ), is probably the most powerful resonance that can be produced on that instrument per bow speed and pressure. Also, the viola's size and dimensions are crafted to take advantage of this tonal range. Know where the instruments tambre and outfitting fits appropriately in your string arrangement, and you get closer to the live sound.
The fundamental harmonic series on the G string, now a C fundamental cuz' it's fingered, will respond in 'sympathy' with the open C string, and vice versa, but even more so because the true fundamental of the physical G string rings sympathetically at the perfect fourth node in response to the powerful vibration of the open C string. More simplistically, if you only play the open C string, the G string will begin to vibrate quite activly at it's fifth harmonic nodes. So if you have the Violas or Cellos pedaling on a C, then you might want to add a delicate touch of the G sonority thinking of that G sonority harmonically. This will give you the truer sound of an open C string ringing on a Viola or Cello. And yes, this practice applies to all notes on all strings in realtion to their harmonic series and the other fingered or open strings they might most excite.
Conversely, Fingering a minor third above the C string to produce an Eb sonority, and then fingering a minor sixth, (with the fourth finger on the adjacent G string), to produce an Eb an octave above is a much less harmonically active sonority, not near as powerful as an octave sounded with an open string fundamental.
Eb does not occur in ANY of the open strings' harmonic series, therefore you need to put LOTS of vibrato into an Eb and treat it extra special deliciously to get it to sound nice. Eb is a pretty dead note on all of the chin and endpin strings. This is why many persons listening to a symphony in Eb may remark the tones the string sections give off sound darker or less vibrant than say a Motzart symphony in G Major which might sparkle and ring in a much happier sonority. And there are three flats in Eb making for even fewer notes that we are able to produce sympathetic harmonic resonance with, within the instrument's overall sonority.
And no, this was not easy for me to understand, but when I did, it was a nice bright light in that phase of my training. It's now up to you to take this and try to convert that into electronica. I'll stick with the real instruments and count on you to fill me in on tips and tricks transfering some of this to electronica, lol.
I would say that when playing in the major keys, or minor keys based on the open strings, (the key of C, G, D or A; minor or major), think 'resonance', harmonics and overall vibrance.
When in keys with lots of flats or sharps, think darker and more somber, because this is how the instrument wants to sound. This is sometimes thought of as a limitation, but really it's up to the ear of the behearer. I think Gb major can be quite beautifully utilized, but I wouldn't pick it for a happy country tune with fiddle fills, I'd pick the key of A or E so as to utilize the open string's harmonic series more readily.
I hope I have helped, I love to try to put these kinds of things into words because it helps me too.
One day, I will write about this again, as it is so critical in producing the sounds that please us on these instruments.
Peace, and may the energies of music fill your body, mind, spirit and soul transporting you into the harmonic resonance we may all seek.
