The physics of bowed instruments
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- เผยแพร่เมื่อ 5 พ.ค. 2021
- How do bow and string actually work together? How do they interact to make a tone on a string instrument?
In the course of his or her life or career, every musician discovers what a tremendous influence the bow has on the sound quality of the instrument.
To really understand and to gain deeper insights into this topic, it's necessary to figure out some basics first. So, at the very beginning, the question arises: What is music, actually?
In this video, Bernd Müsing, founder of ARCUS/Bernd Müsing KG, gives an thourough overview of the physical, scientific backgrounds of sound production in string instruments.
In doing so, he develops his very own theory, namely that the bow itself resonates and that the quality of this vibration in turn has a very significant influence on the sound.
We hope you enjoy this interesting, educational video!
Find out more great things about our bows on www.arcus-muesing.de/en/home....
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A big thank you to the fabulous Alexander String Quartet for letting us use their fantastic performance of the Dvořák Piano Quintet in A Major, Op 81 - III. Scherzo:
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I've been trying to model a quartet sound on a synth for about a week now and this video has been a fountain of useful information. :)
Glad to hear that we could help! 😍
Much old ground for me here, but how I wish you could have been a tutor when I was writing my thesis on the design of concert halls and studios. But that was so long ago you didn't yet exist. This is such a really clear exposition and adds much to what was known at that time. Not only that, it is very natural. This kind of resonating though does respond to and react with the room acoustics in which instruments are played, adding even more complexity. This of course being the resonating surfaces and reverberating air.
Brilliant!
Thank you so much Michael, I am very much flattered.
wonderful to hear such a nice dissection of this phenomenon
Thank you
Very interesting , scale lenth of instrument also has its effect my shorter scale basses 30 1/2 " has a greater fundemental tone verses my longer scale basses 34" and 35" have a richer overtones . I have noticed that the string wave travels back and forth from the nut to the bridge , I think that the string also rotates right and left at the same time in the core as stike slip fault does during an earthquake. I enjoyed this topic very much.😊
Hello Michael, indeed, every component of the instrument and the bow has an influence on the sound. Normally a longer string should provide a stronger fundamental and a shorter string more overtones, but there are so many other elements at play here, for example the size of the bass bar, the wall thickness and material properties of the plates, the neck angle, the position of the sound post,...
I know this is quite a tangent but the forces and motion between the bow and the string remind me so much of the way tectonic plates (pieces of the earth's crust) move at a plate boundary. They are pushing against one another, stuck together by friction, until the force is too great, causing the rocks to break and the plates to "slip" or move past one another. The energy is released outward as an earthquake wave, much like the resulting waves that travel through the string and air when the bow and string "slip." In a violin, this cycle might repeat hundreds of times per second, while in our earth's crust it may happen in cycles that take hundreds or thousands of years.
Hello Kevin, wow, yes, that's exactly the same stick-slip motion! I never tought of it in this connection, but you nailed it.
Also - thank you for making these videos! I find them fascinating from an engineering perspective as well as a musical one!
Thank you for the kind words, and it is a great pleasure to see they are finding an audience. :)
Wonderful video thank you very much!!
The pleasure is all mine.
Thank you so much for this lesson. Both as an engineer and a cello player, this resonates strongly with me (pun intended :) I have learned more than a thing or two that I didn't know, and it changes my view on cello playing. And as a side-effect some new ideas on how to damp some of our mechanical constructions better - the other way around.
Hi Tim, for me it was the other way round, developing suspension systems for bicycles gave me a good basis for understanding and designing bows. For most people this seems weird, but I guess you will understand perfectly well.
While my Arcus bow was made by a former cycle-frame manufacturer who plays the violin, my own violin was made by another violin-playing engineer who originally specialized in designing earthquake resistant buildings for Christchurch, New Zealand, where avoiding and diversifying resonances and damping them was crucial! Dr Nigel Harris also made a matched set of instruments that launched the careers of at least two professional string quartets, so "Here's to the engineers! "
PS I've just read the comment on stick-slip and earthquakes -- so Dr Harris's violins exploit the same stick-slip process as the earthquakes he was trying to proof buildings against -- a fine joke!
I would love to see how the bow reacts to the stick-slip effect. You showed the resonant modes of vibration of the violin, and of the string. How does the bow and bow-hair system flex and what do those resonant modes look like? These would, I believe, be the changes of shape where the bow's damping (and pehaps the bow hair's, with stretching?) would take effect. Hmm. How elastic is the bow hair and what damping effect does it have?
The dampening effect of the hair can be quite important, which becomes especially obvious when you put synthetic hairs on a bow. Plastics like PA have a lot more damping than horse hair (which is by the way similar to wood), which when put on Arcus bows degrades the bow roughly two classes. So a T7 becomes a T5 effectively.
The vibration modes in the stick are quite complex and are even more complex to determine in combination with the stick. They are relatively easy to analyse on a free vibrating bow that is not in contact with a string, but that is just as pointless as testing/measuring a violin without a bow drawing the strings. This is just over-simplification and gives meaningless results.
I have not found a way to make a scientific analysis of the vibrational pattern in a bow stick and I'm also not sure that even if we could do it, if it might help us make better bows. Still we have made tons of experiments and have come to some pretty clear notion of cause and effect and use these principles in the design of our bows.
6 comments\716 views. Shame. If I wasn't misinformed, each comment in some way, helps the TH-cam Channel 'provider' meaning you. This is appreciated, thank you for your work & time.
Thank you. We hope it will be useful for many people.
Just checking again, today we have arrived at 1,616 views and 12 comments. For such a complex and specialized topic not too bad, eh?
Thanks very much indeed Bernd for this video. I now have a much better understanding of what is actually happening when I bow my viola. Seeing the moving kink in the slow-motion string vibration was particularly valuable.
You introduced many key principles very effectively and with terrific enthusiasm.
I'd be very interested to see Part Two of this video, where the principles are applied practically, For instance, how do these ideas work specifically with the basic bow strokes, and then perhaps with some of the more advanced bowing techniques? My guess is that you could identify and explain physics-based reasons why things happen. This understanding might enable more informed practice.
Thanks again for such a valuable resource!
Hello Peter, many thanks for the praise. The idea for a second part is a really good one. I will absolutely think about it and give it a try. Still, there is a rather long list of other important videos that have to be produce before that, so it take a while.
Do you own an Arcus bow yet? Have you made some comparison with other bows at the extremes of the playability-envelope?
@@ARCUSMuesing Thanks Bernd - I'm enjoying a Musing C3 viola bow and currently arranging to have some T and P series, round and octagonal Arcus bows on trial.
I'm an enthusiastic amateur who has just acquired a lovely old 42 cm viola with a string length of 37.5 cm. I'm wondering how justifiable it is to be looking at your series 7 or even series 8 bows. I am nowhere near the ability to test "the extremes of the playability-envelope"!! My aspiration is that the bow can perhaps help me to get a bit closer to the lovely sounds I can imagine but cannot yet produce!
(Playability-envelope sounds as if it's probably a translation from a terrific German word - Spielbarkeitshülle?)
@@PeterButton I actually too "envelope" from aviation en.wikipedia.org/wiki/Flight_envelope
I'm a long-time Arcus user, with a 2002 model violin bow of the type from which I had to strip the glossy black paint as you described in one of your videos. This Bow and String video explains a lot about the role of resonance and damping in the string, bridge and instrument, but does not properly connect them to resonance in the bow stick, on the basis of which you calibrate your bows. I'm trialling a lovely T8 right now and its playability hardly differs (in my hands) from that of the 2002 model, although it certainly differs from an M-series bow that I tried. What I'm hearing, though, is a far greater clarity and purity of tone (less untuned whoosh) from the T8, which obviously has a much more uniform and resonant stick than the 2002 bow, which is itself far better than any cheap CF bow.
What bothers me about this video, though, is the absence of any discussion of how the properties of the stick itself (which you use when calibrating and pricing it) get to interact with the string -- obviously, it has to be through the hair, and I'd assume through *longitudinal* (tension/relaxation) waves in the individual hairs, contrasting with the mainly lateral movements of the string. So what are the typical damping properties of horsehair, and how do they affect the ability of the stick to modulate the sound generated at the contact point, which of course varies greatly in position along the length of the hair? Also, how fast does sound travel in horsehair, relative to carbon-fibre, and is this relevant? My guess would be that sound would travel very roughly at 1400 m/s in the stick material, as in most plastics and woods, i.e. much faster than sound in air. A bow is roughly 70 cm long, so such a wave might travel the full length of either the hair or the stick in about 1/2000 sec, which puts this dimension well into the range of musical sounds. The physics of this would also be highly relevant, I'd imagine, to why different bows sound different. Any thoughts on this?
By the way, I think you're wrong, Bernd, in your comments about bow direction changes, not because of the physics but because of human perception. When I edit a recording, there's a limit of perception at roughly 15ms, below which the human ear/brain combination just doesn't detect a break or cross-fade. If the circular motion of the stick-slip cycle reverses direction faster than that in a smooth bow change, it will be inaudible, so that's "all" the player has to aim for, not some theoretically impossible instant change. But otherwise, GREAT STUFF!
Hi Jeremy, I'm glad to hear you are happy with my bows. First of all let's get one fact out of the way - the velocity of sound along our bows is around 7,300 m/s, a lot faster than in most other materials. Pernambuco for example goes to maximum 6,500 m/s.
You can find the reason why the T8 offers a significant cleaner sound than the 2002 Arcus bow simply by cutting both sticks up. :)
Well, actually, I will tell you. You will find that the stick of the T8 looks a lot smoother on the inside. You probably know that our sticks are very thin hollow tubes. Getting the walls perfectly even and flat is a lot harder than you might think and we have honed our skills (and tools and processes) year over year just a little further. And while you can hardly tell bows apart that were made a in successive years, you can certainly easily tell bows apart that are 10 or 20 years younger resp. older.
What the more even walls and the more regular direction of the carbon fibers bring is a reduction in damping. And that is something you can actually check quite easily, for example with your ears. :) Violin makers do that same by knocking on pieces of wood, as the resonance it will return tells us a lot about how well the instrument built from it will eventually sound.
Regrading inaudible bow changes, this is something I will look into again whether it is audible or not. You spiked my curiosity and I will run a few tests...
Cool stuff!
Thank you
Congrats Sir - amazing video - I am not a violin player but you have perfectly explained stuff I have been working on - You say at one point that this is 'your' opinion , I totally agree with what you said - Fantastic video
Thank you very much, it was really a great pleasure to make this video. :)
Very interesting, thanks! When you plucked the high and low stings and the low one rang out longer, couldn't the damping be the same in each case, but each cycle is damped by the same amount, that way an octave lower will ring out 2x longer.
The loudness depends on the amount of energy that I put into the string. If I pluck the higher and the lower string with the same force, the output will be the same initially. But if the damping is the same for every cycle, the higher frequency tone will ring much shorter than the lower one.
(If it is for example an octave, the higher frequency wave will reach your ear twice as often, but with each half the amplitude at first.)
22:30
Should have been titled “String Theory” ;-)
Hahaha, yes! 😂
6:50
That's an eye opener, isn't it?