There are inevitable challenges involved in translating a piece of music from one instrument to another. In general, it’s probably fair to say that any good composer will write music in a way that takes advantage of an instrument’s particular construction and abilities. Moving it to a different instrument means adapting to a different set of capabilities. Let’s look at a specific example that occurs in moving the Chaconne from the violin to the guitar.
One of my favorite passages in the piece starts in measure 229 and lasts for 12 measures; I’ve reproduced the first part here (measure 228 is grayed out):
The movement of one voice around the static A in the other creates a palpable sense of tension. Harmonically, since A is the dominant of D it also creates a sense of anticipation, since we know that the A is going to have to give way to D at some point.
Bach uses this technique a lot in his organ music (as did many Baroque composers), and it became known as a pedal point since the held pitch was usually played on one of the organ pedals. The pedal point often appears near the end of a piece, where it is used to build anticipation before a final climactic passage. It has the same function here in the Chaconne.
On the violin, Bach takes advantage of the open string tuned to this pitch, so every other note in the passage (as marked in my example) is played on this open string; the violinist uses a rocking motion to alternate between this string (the second highest on the violin) and the other pitches fingered on the two lower strings. This is what it sounds like on the violin:
Because it’s played on an open string, the pitch continues to ring out between strokes of the bow, creating the illusion that A is sounding continuously like a drone.
The guitar can play this passage exactly as Bach wrote it (allowing of course for the fact that the guitar sounds one octave lower). Here is the first portion of the passage in Segovia’s arrangement:
Most guitar arrangements that I have seen follow this same example. While it works well enough, it’s very difficult to create the sort of droning effect that the violin can achieve with its open A string. Segovia makes it almost seamless in his performance, but it requires a lot of shifting of the left hand, making it very difficult (if not impossible) for mere mortals to create a uniform tone on the repeated A:
If you’ve been paying attention you might recall that the guitar does have an open A string, but it is a bass string. Using that as the drone string doesn’t work; it drowns out the moving lines and just sounds wrong.
However…moving up and octave does work. I can place my 4th finger on the fifth fret of the top E string and leave it there for the duration of the passage. Furthermore, I can use the same right hand finger to play that high A every time, lending it a nice consistency if I pay attention and play it correctly.
Here is an score excerpt of the version I’ve settled on along with an excerpt to show how it sounds:
Having the pitch played at the same place on the same string by the same finger gives me the closest thing possible to playing the A on an open string and creates the same kind of drone effect as the original. As with any good translation the particulars are changed in order to retain the spirit of the original.