What makes strings sound "sweet"?


I have always wondered about this. If you listen to many recordings of bowed string instruments, then you know that the upper registers can sometimes have a sweet tone. I define this by what it is not - edgy, brittle, dry and rough sounding. It is smooth and inviting. I used to assume this was due to rolled off highs or an emphasized midrange, but I am not so sure. It varies by recording, or course, but I have often wondered what, in the recording or reproduction process, causes strings to either sound brittle or sweet. Is it the acoustic of the original recording venue? A frequency balance issue? I would love to hear from those who might know. Thanks!
bondmanp
Bondmanp - To obtain sweet sounding strings pay attention to:

1. Pressure of the Bow: This certainly can affect tonal quality...experiment with adding slight pressure and increasing it as you draw the bow. The first finger of your bowing hand is where most of the pressure is applied. You'll want to work with a qualified teacher on this since bowing technique it's such a critical aspect of learning to play well.

2. At what point on the strings is the bow applied. There's a "sweet spot" where the strings are the most responsive to the drawing of the bow without any harshness in tone. I've found this to fall right at the end of the fingerboard. You'll want to experiment yourself to determine where the "sweet spot" falls on your violin. Many time this can be directly between the end of the fingerboard and the bridge. If you play above the fingerboard, the violin loses presence and volume. Even so, you might some songs call for this mellower tone. If you play too close to the bridge, you'll notice that the sound becomes more trebly...and has a certain whistling quality.

3. The bow needs to be in a straight line above the strings drawing a perfect plus sign. As you draw the bow over the strings, you'll want to focus on keeping the bow as straight as possible...the plus sign should be as accurate as possible throughout your playing. Try practicing this technique by drawing the bow from the lowest part to the tip of the bow. As you draw the bow its entire length, carefully observe the angle you're playing...and make sure that you're drawing a straight line across the strings. Keep the speed of the bow consistent...be careful to allow the bow to exert its own pressure, against the string, through natural gravity.

4. Are you using the full flatness of the hair of your bow against the string. Many good violinists will use approximately 3/4s+ of the hair applied to the string as the bow is being drawn. To do this, simply angle your bow just slightly so that part of the hair is raised closest to you. Again, you'll have to experiment with this to determine if it improves the tone. You may find that variations of using both the flat surface of the hair and 3/4s will contribute to songs in different ways. Experimentation is your best research.

5. How tight is your bow hair? When tightening the bow hair, be sure to leave it slightly loose and not over tighten. Over tightening the bow hair leaves too much tension and can affect the tone and the arch in your bow. The wood of your bow should still have a very slight arch to it after tightening the bow hair correctly (it should not be a straight line). You should be able to tap the bow slightly on one of your fingers and determine that the hair will barely touch the wood part of the bow.

6. Did you apply just the right amount of rosin? If you have too much rosin, there will be a scratchy sound as you draw the bow...with too little, the tone will seem to disappear as you draw the bow. If you find that you've applied too much rosin, do not attempt to clean the hair. Cleaners and Oils can ruin the capability of the hair to grab the string and create a clear pitch. It's best to play until the rosin slowly dissipates. If you feel that the rosin doesn't appear to be applying itself to your bow, this can be determined by gaining a whispering tone instead of a full clear pitch, try sanding the cake of rosin with some sandpaper so that it has a rough surface.

7. Do you have the proper grip on your bow? A few things to consider include: do not grip your bow too tightly, do not add unnecessary pressure to the bow, be sure to rest your little finger on the top of the bow, and keep your entire bowing arm and hand as relaxed as possible.
Thanks, all. Very interesting replies. Kijanki - thanks for all the info, but my OP specified "recordings" of bowed string instruments. Music is, for me, stricktly a spectator sport. :-)
Ahh, yes. This is absolutely the hardest element for a stereo to convey. I used to think bass was the hardest. Then I thought the midrange was the hardest. Now I appreciate that the sweet, angelic, gripping sound, detailed, grain-free sound of the treble is one of the most magical, mesmerizing, and elusive pieces of the puzzle.

The recording is important, but so is your stereo. I have built my stereo in the quest for this sound. Everything contributes, although I place high emphasis on the Jade Audio cables, the preamp, the Tripoint Troy, and the diamond tweeter. I believe it really becomes an issue of striking the correct balance of frequencies throughout, and removing all the noise (both heard and not heard).

It is so fragile. Just changing one cable can kill the magic. If you have it, be careful not to touch the stereo again or all is in jeopardy.
Bondmanp- It was intended as a joke but in a process I learned how difficult it is to play violin. In addition to technique and intention of the player there is a sound of instrument, acoustics, recording techniques etc. Radiation pattern of instruments can be also strange with some instruments like cello projecting only to the rear at certain frequencies.

Strings sound much better now with my my new speakers but I can hear big difference between recordings varying from sweet earthy tone with beautiful harmonics to high pitch screeching sound. My gear have deficiencies, I'm sure, but some recordings are just plain wrong and no gear in the world would make them sound great.
"This is absolutely the hardest element for a stereo to convey. ... The recording is important, but so is your stereo."

Agree 100%. Subtle weaknesses in source, pre-amp, ICs, and/or power amp together will often exhibit themselves here during a well recorded sustained string note. Speakers too but perhaps to a lesser extent in general in this regard. To get this detail to sound consistent and natural and not distorted in subtle ways from start to end is an ultimate test. I used to think that this was the blatant achilles' heel of CD digital. Now I think it may still be the weakest area of CD sound recordings, but not to the extent where it always must sound problematic due to the recording technology.