Some of the easiest things to play on a stringed instrument can be the hardest to emulate from a keyboard. Vibrato is a good example: most solo string samples include vibrato in the sample, which is by far the best way of achieving maximum realism. However, it can also be very restrictive.
“The problem with having vibrato sampled into the sound is that you have no control over it,” notes Tschetter. “If you can control it yourself using an LFO, you’ll have more freedom to use and assign it as you wish, depending on the style of music you’re performing or programming. For example, country fiddle players have a very wide pitch depth on their vibrato, so you want to set that parameter accordingly. It’s nice to control filter, amplitude, and pitch for vibrato; if you can control the depth with the modulation wheel and the rate with Aftertouch, it can sound really good.”
“It’s very important to change the vibrato rate depending on the type of music and also the dynamic,” agrees Brubeck. “String players in general vibrate faster when they play louder, and in earlier styles of music, such as baroque, vibrato would only be used as an ornament, whereas in later styles it’s more of a constant.”
It’s also worth bearing in mind that the lowest note on any stringed instrument is always played sans vibrato. The same thing is true if you’re emulating a string player tuning up, where they would be bowing or plucking only the open strings.
On the subject of plucking, or pizzicato, most orchestration books note that string players generally can’t do fast pizzicato runs, and that’s something to bear in mind if you’re playing or programming in a classical idiom. However, there are exceptions to that rule, as Brubeck explains: “If you want something to sound orchestral, you can’t use techniques that nonorchestral players have worked on. Acoustic bass players who are schooled in jazz, for example, can play pizzicato a lot faster than classical players simply because they spend more time doing it. The same is true of cello; I can play pizzicato much faster than most cellists because I use a 2-finger technique, whereas most cellists are trained just to use one finger.”
Another common string effect is tremolo, which is rapidly repeated, short-bowed notes. Because it’s impossible for a keyboard player to restrike the keys as fast as a string player can play tremolo, this is another effect that works best when recorded as part of the sample. But what if your synth doesn’t have that sample? “Try using an amplifier and filter LFO with a square wave shape going really fast and deep,” suggests Tschetter.
Occasionally your string line may call for a glissando; simulating that is almost impossible. Depending on the style of music, there are two ways to go. Using regular Pitch Bend can work for the clich?, Psycho effect. However, string players often perform glissandi by fingering and playing each note individually. A standard keyboard glissando is the only way to attempt this, although you’re restricted to a diatonic scale along the white keys (and exact pitches), which isn’t altogether ideal.
“A glissando is something I wouldn’t even try to play live!” says Zink. “I’d program it into a sequencer and probably draw in the bend. If you listen to a string glissando or pitch bend, you’ll find they tend to start off slowly, and then they’ll go faster, so you should draw a curve that is not completely linear. There are often some other things going on, though, such as volume changes and tonal changes, so you want to use a filter as the bend occurs. On the XG, for example, I’d use Controller 74 [Brightness] to control the timbre on this effect.”
If you want to produce music at home like a pro then take a look at my BTV Solo Review. You’ll be amazed what you can do with a little bit of software and some passion.