Orchestration, Doubling Etc.

Just a basic question. Let's say you use strings only. Violas double the melody played by violins (in octaves), cellos play the harmony and DB doubles it. That's it, only strings. Does this alone - strings alone - create intensity, or must we necessarily add woodwind, brass to create such intensity? I am not against using brass/wind, just out of curiosity I would like to know whether strings alone would produce the typical orchestral effect.

you can. 3rds and 6ths between violins will help. Always adding extra things, even if just a single solo woodwind, makes your orch bland and gray, as harmonics get blurry. It could very well be more effective to write in 3rds 6th and octaves with strings only for a while, it'd be very refreshing effect after a tutti. Suddenly switching from rather bare 8ves doublings to an 8ve plus 3rds/6th will help build tension from just strings, to 'big' strings, to a tutti of some sort. You should get the 'writing for strings' course from alexander publishing. check out hollywood film scores, those sappy high pitched string parts.

well, you're the only one who really knows what you want, I'm not sure what you mean by intensity. I suggest you try it out, you definitely don't need woodwinds or brass, but to get what you want, use your ears, and try to figure it out. I'm sure that'll work out better than asking others about what you want. hope you figure it out

So you are writing for a string orchestra and you want to know how to create intensity within this set up?

Multiple stops are a good way of thickening the texture that in turn will increase the dynamic and intensity. Care needs to be taken with these though due to playability, and tuning particularly in ensembles.

I think intensity is easier to build following sections that are not so powerful. For example you could have the double basses not playing and the viola's or a violin section could rest through more gentle parts of the music. Mutes can be effective also. If you have a thin, light section you can then easily erupt into a more fuller and seemingly more intense section.

Parts don't have to always be playing.

It easier to create interest and intensity with larger orchestra's though limiting ourselves can make us more resourceful.

There are also a variety of articulations you can use to make strings sound intense such as staccato, spiccato, and accents. Fortissimo tremelo/ very fast notes can also have a very powerful effect. Here's an example of some very fiery writing for string orchestra:

All Violins + Violas in 8vas in an intense sound indeed, just it depends on the passage, if is an almost solo melody can work, if I care about harmony too I would fill with horns and other stuff, since you have something like 16+16+14=46 instruments playing your melody and 8 basses your bassline, you only have 10 cellos for 1 note ? if chord is perfect and melody covers the rest, or you'll have to divisi your 10 cellos, so a C major chord will sound like G on 46 instruments, E on 10 and C on 8, I don't think is a good balance, I can fix it with horns, or trombones.

Violins I and II in 8vas is already intense.