Oh my. We went to see the Borodin String Quartet the other night and I noticed that from time to time the musicians would move something up to the bridge. I’ve never noticed this sort of action before and was wondering what function it performs. Is it a damper of some sort? It seemed to be used more when some serious plucking was being done, but my ears couldn’t tell the difference when the instruments were being bowed. Thanks.
Maybe they were mutes of some sort? I have seen such things in use, I believe, but not often. They give a bit of muffled sound like the soft pedal on a piano.
Can you descibe how they looked? My memory has a comb-looking thing that attached to the top of the bridge. That close?
Certainly sounds like a mute. Mostly made of black rubber, with small circular ones more common than the comb-shaped ones. Here’s mine in place.
That looks like the ones on the violins. The cello had one that was more like a comb. So does it act like piano pedals and damp the tones?
What’s the difference between a violin and a viola?
Could it be a capo? Like on a guitar when you want ot raise the octave?
I don’t know what it is but if it’s near the bridge it’s not any kind of a capo, which has to go on the neck. I’ve never heard of a capo for a bowed instrument (although that doesn’t mean it can’t exist). But a capo is not really necessary. A capo on a guitar is so that you can play open chords in a different key, that is, play chords that include open strings (this is done mostly by strummers who accompany their singing and never learn anything but a basic set of open chords). On a violin/viola/cello, you can play double stops (two strings at once) but due to the geometry of the strings and bow you don’t play chords AFAIK.
A viola burns longer?
or
You can throw a viola farther?
No difference at all. The violas just look bigger because the violinists all have swelled heads.
Somewhere, in a seedy bar, a double bass is crying into his drink and wondering why he is always neglected.
You can - either spreading them (equivalent to strumming a guitar), or in the case of short loud chords it’s possible to hit all four strings at once. They’re arranged in a curve, but the combined flexibility of strings and bow hair makes this possible.
Because he’s viol.
I’ll be leaving now
It’s true–the double bass is the only bowed string instrument that still has sloping shoulders like the old viols of the Renaissance. The other 3 have shoulders at a right angle to the neck.
Basses are also tuned in 4ths rather than the 5ths, another trait from viols.
More or less - you’re putting a lump of soft stuff in contact with the vibrating part, absorbing some of the vibrations. The volume goes down and some of the higher overtones are lost, not unlike the celeste pedal on a piano. The result is sweeter but not so penetrating. The musical direction is con sordino to place it and senza sordino to remove it.
Trumpeters have mutes too, but they come in an assortment of shapes and do different things to the tone - a straight mute makes it quieter but tinny, a cup mute makes it softer and rounder, and so on.
Historical influences aside, basses need to be tuned in fourths because you would need to have gigantic hands to play the notes if they were a fifth apart - as it is, in the lower positions (higher up the neck) the bassist can use only first, second and little fingers as it’s not possible to get enough of a spread to make the third useful.
If he is there with his friends, then are the basses loaded?
Nice twist on an old joke
He’s upset because there’s always room for cello.
Yes, those things are mutes.
To answer the spinoff question about violas and violins: violas are a little larger than violins. Violas have a C string as its lowest string and an A as its highest (for violins, its G and E, respectively). They have a deeper sound and usually support the harmony along with the cellos, which share the same strings. Violins, in contrast, play treble.
In terms of superiority, violins reign. All the other instruments just wish they could be as badass as the violin.
The stringed instruments resemble a four-part choir, so I’m told. The violins are the sopranos, and sometimes divided into first and second parts just as first and second soprano parts are sometimes split. The viola is an alto; the cello a tenor/baritone. And the double bass is a basso profundo.
Also, as Johanna points out, the double bass is constructed differently, with a curved rear soundboard and sloped “shoulders” – the “violone” and “viola” schools of stringed-instrument construction (though the viola itself is an alto violone, not a viola – the viola da gamba of the Renaissance was a tenor viola, played like a (violin)cello.
What’s the difference between a dead snake in the road and a dead trombonist in the road? 
The snake was on his way to a gig.