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Overtones - Good or Evil


Tenor1
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Bowed string instruments sound more overtones (also called "patials") than any other type of instruments. That is why they sound so great and unique and why so much can be done with them. There are about 20 - 25 audible overtones from each note on the lower strings. The proportion of the amplitude (volume) of each partial to the fundamental tone and to each other are characteristic of each individual instrument. Each instrument acts as an amplifier of the various vibrations of the strings, but the amplification ratio for different frequencies is selective. Different strings seem to have different strengths of vibration of the diffrent overtones so that by trying different strings you can change the input to the amplification by your instrument and thus "tune" the output ratios to more closely achieve the ratios that sound right to you and optimize the sound from your instrument. (Also be aware that changing the tension in strings changes the instruments performance as an "amplifier.") Another intersting factor is that thicker, less flexible strings often have more overtones that are slightly off harmonic ratios to the fundamental tone and add an even more complex character to the sound - some people like that, some don't. To hear this kind of "anharmonic" overtone, try plucking the lower strings on a piano - or just carefully listen to the differences you hear progressively in time after striking a low key on the piano.

For those low fundamental tones whose wavelength is longer than the length of the instrument's body, such as those on the lower G string, the amplitude of the fundamental tone is lower than that of most of the partials and virtually all of what is heard is actually overtones (Vengeroff's Strad is particularly notable for kind of sound).

The proportional volume of each fundamental and each partial (assign them numbers [1st, 2nd, etc], if you like) to the fundamental tone varies continuously and thus is different for each semitone you might play. However, the total volume of sound each note brings out (sum of fundamental tone and all audible partials) is quite consistent (I won't go so far as to say "constant") on any good instrument. By using vibrato, you actually engage the surrounding partials and further enhance the volume of the instrument and contribute to more balanced sound and greater tone color. I think it's really amazing.

Using a mute dampens all but the few lowest overtones - and a really heavy practice mute can dampen them all - which is why it sounds like a Tonette. If you don't like these overtones you might want to switch to playing a Tonette. Or if you like violin but not overtones, you may be fortunate because your instrument of choice should be most inexpensive.

Andy

[This message has been edited by Andrew Victor (edited 02-03-2001).]

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Overtones is one of those words that mean two completely different things to two different people. Andrew's description is one kind of overtone but as a guitar player I use the other definition and use harmonics or partials to describe what Andrew wrote about.

Play a G note on you violin D string and make sure that you aren't touching the open G string. When you bow G on the D string the open G string will begin vibrating. If you stop playing G on the D string the open G string will keep vibrating at that pitch. Also bow your open G string without touching any other string and your D string will start vibrating at a high pitch, this only works if everything is in tune. In the violins that I've built the best sounding ones have had the most overtones. They just come naturally with a responsive instrument.

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William-

OK, if you want to call it that. They are all sympathetic resonant vibrations, if you will, whether from vibrating strings or wood - but you will not hear them unless the wood vibrates in response to them.

Along the lines you have discussed, players will often vibrato the 3rd finger (1st position) on the next higher string when playing an open string (usually G, which can not be played in any way but the open string) because it varies the pitch of that "partial" and so contrubutes a vibrato sensation to the sound.

One more thing: It is certainly possible to have a very poor balance of partials on a particular instrument. Just as you can have too little of this you can also have too much, which can also mean poorly balanced in terms of desirable musical sound.

Andy

[This message has been edited by Andrew Victor (edited 02-03-2001).]

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Listen to the hard tone from a sine wave generator and you'll see why overtones are needed. No mechanical vibrating medium is without them.

What your luthier may have been referring to is 'partials.' These are the overtones that are not integral harmonics. I've been meaning to start a separate thread on this to ask some of our physicist/engineer members how these overtones are generated and how they contribute complexity to a violin's tone. Any takers?

Mark_W

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Fred,

Maybe. When I draw the bow and have the Korg tuner on, a single note will not only register itself, but there are other notes to either side - maybe these are partials. There is a ringing that lingers, a ringing in the note's tone, that carries as I switch to different notes. It might sound by my description that this would be distracting, but otherwise it would sound stark and unfulfilling, as it did on my old violin. I don't know if I'm using the terms correctly, but the richness in sound, like ripples in water, has added a dimension that didn't exist before.

-Greta

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Bink,

You raise a tough question. I'll try to approach it by first excerpting from an e-mail I sent to Bernd at Arcus last week regarding some violin and bow "trials":

"$14,500 Ouchard was outstanding - great handling and

incredible sound on all the 9 violins in the room. It is especially fine on her wonderful

Marchetti - it really is an incredible violin (in my experience). Next tier

down in sound were my Voirin, and the $8,500 Thomassin that "she" brought, and my

Weichold. I'd say next below that was my Arcus Concerto - good sounding among

the composites - only slightly more suppression of the overtones than the bows

I've ranked above it. Below that, the sound from the bows - Berg Deluxe clear

on down to a Glasser Composite - did not seem substantially different. Of course,

they each handle differently - and that would probably determine ones choice

(besides price)."

My continuing experience with Arcus Concerto and other bows continues to intrigue me. What is clearly an outstanding bow on one instrument, may not seem as good -even in relative rankings - on another.

A few things are clear to me. Just as one instrument (violin, viola, or cello) body will amplify different frequencies from the string vibrations by different amounts than another, so one bow will bring out that balance of frequencies on a given instrument in a different balance than another. If you have a preconceived notion of the "right sound" then one bow will bring you closer to it than another.

The strings are also avariable in providing frequency input to the instrument for amplification. Then too, the setup of the instrumnet can change the balance of the sound. So you have these four variables.

The complexity depends on how many of these factors you are bent on changing.

If your major purchases are complete, then you can only vary the strings and the setup.

If you are looking for a new bow - then variation of strings and setup are also an affordable option.

If you are starting a whole new "outfit" : (instrument and bow), then, before you are through you may find yourself looking at new bows and alternative strings.

Although the Arcus bows I've have tried seem to produce a cleaner sound I have not experienced any reduction in amount of sound - if anything, there is generally more sound than with most other bows (notice above the rarified company my last tests included). My Arcus cello bow experiences have been even more interesting - and on my biggest-voiced cello the Arcus is clearly the bow to use for cleanest and most beautiful tone and suppression of "difficulties". Of other bows, a late 19thC Albert Nurnberger is a little coarser, and a Coda Classic and a modern good Brazilian bow (both bows of choice on a modern Chinese cello) are much coarser and cannot provide an even quality of sound on the louder instrument.

What really matters is how the instrument, sounds to a listener - are the overtones being suppressed when you use the Arcus, or is it just surface noise? Have some friends listen, and you listen to them. For my own playing, the feedback from other people when I've used an Arcus has always been good.

Andy

[This message has been edited by Andrew Victor (edited 02-05-2001).]

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Andy; I thought your description was great; never had considered the effect of vibrato in relation to overtones. So, when I switched from a Coda Classic bow to an Argus many of the overtones which did not seem to contribute positively and most of the white noise was eliminated, leaving a more pure sound and beautiful "land of oz" color. I don't have a clear understanding of how that can happen. Any basic explanations or ideas would be greatly appreciated. Bink

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