When I bow an open string on my violin, it sounds sharp. When I pluck the
string though, it sounds right. Harder I bow, the shaper it sounds. I am a
complete newb. Do I need new strings or is it just my technique?
Thanks!

30 responses total.

More rosin, check the hair tension, then tune again.

There are more harmonics when bowing. That might sound "sharp". 

Not to anyone with a halfway decent musical ear.

Nick said he was a newb. But, more technically, if you compare the two with
a pure note of the same fundamental, you might not think it was sharper when
bowed than plucked. 

Just because he's newbie doesn't mean he lacks a musical ear. And 
contrarily, he would have to have an amazingly good ear to pick out the 
harmonic for the non-tempered third which, although it's slightly 
"out of tune" for those used to the even-tempered scale, is also a higher 
harmonic not nearly as dominant as the fifth and octave (which will NOT be 
perceived as sharp or flat). Yer grasping at straws, Mr. Science. 

For an interesting article that says just the opposite of what you said, 
see http://www.phys.unsw.edu.au/~jw/harmonics.html which basically says 
plucked strings provide a LESS accurate pitch (in terms of an accurate 
harmonic series) than bowed strings. In other words, bowed strings have 
more accurate harmonics, although bowing also creates a slight inaccuracy 
in the fundamental pitch due to the "slip-stick" action (presumably 
because bowing introduces additional tension on the string beyond that 
provided by the tuning pegs). The conclusion, although not expressed in 
the article, is that he should be tuning to a bowed note and not a plucked 
note.

The difference in pitch is not the RESULT of harmonics, but rather the 
difference in pitch and harmonics produced by bowing as opposed to the 
pitch and harmonics produced by plucking. To be even clearer, if you were 
able to remove all the harmonics, there would STILL be a slight pitch 
difference. The slight greater change in odd harmonics produced by 
plucking merely makes the difference more obvious.

Good information.  Thanks!

I changed the strings and it holds tone much better. I think I'm also bowing
too hard, which I'm guessing increases tension on the string, resulting in
a sharper pitch. Got some good rosin (the stuff that came with it was like
glass- I couldn't get it off the bar) and now I can bow with less pressure.
That's helped a bit too. I may not be one of the Bachs, but I think there's
a perceptible change in frequency when I stop bowing an extra string and let
it resonate- it goes back to the frequency to which I tuned it. It seems from
what I've learned on the web sites and from experimenting during practice that
varying the speed of bowing is better for dynamics than varying the pressure.
Does all this seem plausible to more experienced people? Thanks for your
suggestions, guys!

Change "extra" to "open" in the above response.  :)

The three "tricks" string players have when trying to exact a
sound is the pressure exerted on the string - how "into it" you
are.  Second, the speed at which the bow travels across the
string.  Third is where on the string you place your bow - closer 
to or farther from the bridge.  There are other variables, of course,
like whether you're on top of or on the side of the string, but
the first techniques are really what you look to first, when choosing
the needed sound.

Re #5: and yet we see string players in orchestras plucking their strings to
check their tuning....

Cyclone is getting entirely too theoretical. I am only saying that a 
difference in the harmonics from plucked and bowed strings can create the 
impression of different fundamentals even without the fundmentals 
changing.

See, for example 
http://lcweb2.loc.gov/cocoon/ihas/html/rreynolds/interview-part3-notes.html

"Fundamental Frequency - The classical physical description of a sound 
involves a fundamental frequency, which is the lowest of a set of partial 
frequencies associated with it. Somewhat surprisingly, the aggregate of 
all the partials is what determines the octave of the pitch that a 
listener hears, and this heard pitch may sometimes appear to be at a 
frequency not actually represented in the signal (the "missing 
fundamental" phenomenon)."

 The actual shift of the fundamentals between a plucked and bowed string 
is a separate issue.

Rane- what I'm describing is a difference of maybe a quarter-tone. I wouldn't
be calling an octave change a "little sharp".  ;)  I think I'll just bow when
I tune instead of plucking. Thanks for your input, all.

The "missing fundamental" phenomenon is one of the possible examples of 
when the "heard pitch may sometimes appear to be at a frequency not 
actually represented in the signal". I'm trying to get at "timbre" 
inducing a perception of a difference of pitch, especially to an untrained 
"ear".

Dude, let the musicians talk amongst themselves about subjects they know 
about. "Ghost tones" represent pitches heard beyond the notes actually 
played, which I guess is what you were trying to say, in your own 
non-musical way. The point you are missing is that there are at least two 
types of "sharp." Notes with higher frequencies (vibrations) are 
"sharper." However, virtually all the harmonics (which by DEFINITION are 
sharp, or they'd be called SUB-harmonics) and ghost tones generated by a 
stringed instrument are in basic harmony WITH EACH OTHER. Nick is 
describing something entirely different, which only you seem not to see. 
He just mentioned he hears the note a quarter-tone off. Except for 
untempered thirds in the harmonic series, there really are no quarter 
tones played on the classical instruments in Western music. I think Nick 
knows the difference between a harmonic and a quarter tone. Do you?

Sorry rcurl, what cyclone said.

Since this came up in Agora... Nick, would you please enter what the
conclusion was on why your violin sounded sharp by a quarter tone when you
bowed the string but sounded OK when you plucked it? Also, please let us know
what you did to correct this. 

Now you ask. ;-)

I put new rosin on the bow and changed the strings. After that, I didn't have
to press so hard to bow, which helped relieve the problem. I also learned to
apply less pressure when I play, which helped. Finally, I bow when I tune now,
instead of plucking, and I'm happier with the way it sounds. It's not exactly
a high-quality instrument but I'm satisfied with it now.  :)

I don't have a violin anymore so I can't experiment, but what do you think 
(or know) was the effect? Certainly increasing tension on a string 
increases the pitch, theoretically in proportion to the tension. A quarter 
tone is about a 1.5% increase in tension. By how much does bowing increase 
the tension? I would expect another effect, which is that bowing creates 
an effectively shortened string above the bow point, which should produce 
some energy at that higher pitch. How significant is that?

Re 18: Are you suggesting I'm bowing at the exact node that would create a
harmonic in a different octave exactly a quarter-tone higher than the
fundamental frequency? Rane, dude, I can't even keep the bow on the string
half the time.  ;)

Re 19: I'm not sure that makes sense haha. It's an interesting question but
I don't have the equipment or know-how to find out for you, Rane. Sorry man.
All I know's all I hear.

Well, I'm sure your estimate of a quarter tone was just that - an 
estimate. And, no, I was not suggesting that you were bowing at a 
particular node. I just noted that you must have been bowing slightly 
above the bridge, and the string above the bowing point has a natural 
frequency for that shorter length, which would be also activated at a 
higher additional NONharmonic frequency. I'm asking if that additional 
frequency is noticeable.

Okay, I think I get what you're trying to say, Rane. IIRC it was the same
problem wherever I bowed, but I didn't really pay attention. I do know I've
played in different places between the bridge and the "finger board?" and it
changes the "color" of the tone a bit but it doesn't change the tuning. I
imagine the little harmonics you're talking about are what's affecting the
"color", which is probably the timbre. If there's a way to eliminate the upper
harmonics while I bow, we can settle that question for sure. Maybe I'll record
it and EQ out everything above the fundamental freq and compare it to the same
situation when plucking. Jesus what a pain in the ass to settle a BBS
argument. You got me curious though.  :)

Again, changing the harmonics ringing above the fundamental will not make
any of those notes sound a quarter tone sharp.

Re 23: We shall confirm through experiment! I only hope my testing procedures
are up to your exacting standards, Rane.  ;)

Yes, do an experiment. But let Rane outline it or you'll probably hear
complaints about your methodology.

Re #23: you missed the new point in #21: there are additional NONharmonic
frequencies created in bowing, corresponding to the string length between the
bow and the nut.

Helmholz has a nice treatment of some issues of violin bowing. He used a
*mechanical* oscilloscope (electronic ones were not yet invented) and observed
the motion of the string under the bow. Superimposed upon the harmonic motion
are what he called "crumples" (in translation) due to the stick-and-slip
friction of the horsehair upon the string, depending upon the location of
bowing. I'm sure all of this has been studied since with modern instruments,
but I did not find a treatment of it on the web.

So do you have a citation or not? If so, post it. From what you are 
saying, there will be a second frequency generated by "stick/slip" and the 
frequency will vary depending on where the bow is drawn relative to the 
bridge. IF that is what you're saying, I call BS. As my earlier reference 
noted, bowing (the cause of slip stick) affects odd HARMONICS, it does not 
create a new frequency. The more scientific explanation may be that the 
slip/stick frequency interacts with the fundamental and its harmonics, 
which creates the effect on the odd harmonics. In any case, the proof is 
in the playing, and I GUARANTEE you that no violinist in the world will 
tell you that varying the location of their bowing relative to the bridge 
creates a quarter/micro- tone change in pitch. And, as you may recall, 
THAT is the subject of this discussion.

Helmholz, "Sensations of Tone".

You may be right, at least for an accomplished violinist. Helmholz makes some
points about the differences between the best and poorer performers in the
tones they produce. 

In any case, to what do you attribute the (approximate) quarter tone
difference that Nick heard between bowing and plucking his open strings?
Please provide citations in support of your hypothesis.

Jeez, you're getting as bad as Richard. Go back and reread this item. I
previously cited an on-line article that clearly explained the stick/slip
action was responsible for the pitch difference. And it has NOTHING to do with
harmonics being a quarter tone sharp.

You wrote "presumably". I was asking for documentation.By the way, the 
article you cite says "Strings and pipes are not inherently harmonic.". In 
fact, they can exhibit power density spectra at any inharmonic ratios, 
like sqrt(2) w.r.t. the prime - or 1.01545.. (quartertone) w.r.t. the 
prime.

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