Oh dear, expectation and pressure. Well, to start here are a couple of pictures:
These accompany the beginning of
this article by historical bowmaker Hans Reiners, which I think is fascinating. His bows are wonderful; I've played on three of his models, and own the one based on the picture above (a painting in Nostell Priory of five English musicians in 1661, presumably members of the King's private music). It is by far the most outcurved of all my bows, and is nothing like the nearly semi-circular things you see in some (usually much earlier) pictures.
If I understand Baz and Ollie correctly, they both seem to assume that a concave bow will always be capable of bearing more tension than a convex one. This is not entirely true. The article above makes clear it's important to consider how the hair is attached. With a screw-adjusted bow, one end of the hair is attached to the frog, which then slides back and forth. If you do it up too tightly, the frog starts to pull away from the stick - a clear sign you ought to stop winding! With a modern bow, I was always taught never to do it up to the point where the stick starts to straighten out - having some give and gentle springiness is important to spiccato techniques that you don't really use in earlier music (at least not in the same way).
With a clip-in frog, both ends of the hair are attached directly to the stick. Tension is created by inserting the frog (basically a wedge) between the hair and stick; it stays in place by slotting into a pre-formed groove that keeps it from moving around once it's under tension. The woods they would have been using (yew, well-known for making more lethal kinds of bows, and later snakewood which is even better at combining strength with flexibility) were capable of holding huge amounts of tension without distorting or breaking. So the fact of an outcurve is no indication of looser tension - if anything, the higher a frog you insert, the more outcurved the bow will flex, and the more tense the bow will be.
Some reproduction baroque bows do have screws in place - it's a useful compromise when, say, touring through many different climates or getting on lots of airplanes (humidity and temperature changes affect the hair pretty drastically). My "standard" early 18th century bow, made by
these makers, has an inauthentic screw (ahem, no sniggering at the back). But I always do it up to a tension that's more similar to a clip-in bow than a modern concave bow. It simply works better that way - the sound is clearer, more focused, more various and supple too.
Baz mentions adjusting the tension of a bow by thumbing the hairs. This is a gambist's technique using an underhand grip placing not just the thumb but also some fingers around the hair in such a way that enables the player to "pull" slightly at the hair and increase the tension. Violinists never did this. It is true that in the early 17th century many violinists would have placed their thumbs on the outside of the hair, but this was just a style of grip.
So from my experience (and I spent a long time looking for the right bows, still not quite there yet and made a couple of mistakes along the way - anyone want to buy a Matthew Coltman pre-classical-twig-hybrid thingy? it's very nice, just not something I have any need for), the outcurve is more pronounced the earlier the model, and the more pronounced the outcurve the
more tense the bow is, therefore the more difficult it is to play simultaneous or near simultaneous chords. The more tense or strong the bow is (within limits), the easier it is to make a good sound on uncovered gut strings at an appropriate tension (quite a bit higher than on a gamba).
But is it really desirable to play chords simultaneously? This is maybe the bigger question. Would it actually sound good (I won't even mention whether it's "historically appropriate") to have the bow able to sustain over 3/4 strings at once? One thing that makes contrapuntal writing interesting is being able to
differentiate voices. Having a blanket over all notes at once would distract from that. Also consider for a moment an instrument which is capable of having up to 10 notes sounding simultaneously - the harpsichord. How annoying would chords sound on that instrument if they were all always played simultaneously? Most players will spread even a double-stop. Harpsichordists always seem to save simultaneous chords for very special effects - moments of "stopping" or hesitating. Even pianists playing baroque music on their steinways seem to appreciate the musical possibilities of spreading chords. On chamber organ perhaps spreading is less frequent, more contained and less noticeable, but on that instrument you can hear that the really interesting players will vary the
release of notes in a way that will emphasise a certain voice or line over others.
The other problem with imagining that one's equipment ought to be adapted to enable easier chordal playing is that no piece is ever entirely chordal. Every fugue has an episode, every chaconne has its more linear variations. At the same time, thinking that only the chordal writing is contrapuntal also does a disservice to the player, who ought to learn to bring out different voices and an underlying bass even in the linear passages. These two aspects of playing are actually more similar to each other than all this talk of technique and equipment implies.
One more thing - Bach's use of the
arpeggio abbreviation. This can be traced directly to Biber (although he spelled it
harpeggio), and is really no more than a shorthand that allows the writer/engraver not to have to spell out loads of hemisemidemiquavers. It is only used when arpeggiation of a long chordal passage is supposed to happen rhythmically. This is quite different from spreading chords - which, while it shouldn't happen in a way that disrupts the overall rhythm of a piece, does not follow a prescribed and notatable rhythmic pattern. Sometimes you spread quickly, sometimes slowly. Sometimes you start quickly and finish slowly, or vice versa. Sometimes you spread over the four strings very distinctly, sometimes you blur the adjacent notes together into double-stops. Sometimes you linger on a single note somewhere. Sometimes you lighten the touch as you spread upwards, sometimes you practically crescendo upwards. But you very, very, very rarely ever spread downwards, even if the prevailing line is in the bass.
Ok, I've wittered on for long enough. Let's see how many other replies happened while I was writing my reply.
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Only the one - I'm here, I'm here!
