Labels:text | screenshot | font OCR: -=-=- 2-2-2-8-8-2-2-2- OTAL IRRELEVANCE =-=============- 8-8-8-2-3-3-3 Orchestrating with MIDI A guide to the process and techniques by Kevan R.Craft (c) 1993 As MIDI music is being used more and more in professional productions for Film, Television and sound recording there has been a move towards making the MIDI music, especially classical orchestrations to sound more "real". With this in mind we'll examine the instruments of an orchestra then we'll discuss the difference between velocity and volume, and what that means to the orchestral composer, and then talk about other types of expressive control. Finally we'll discuss mixing and processing techniques. PERCUSSION AND TIMPANI The percussion section of a symphony orchestra is quite different from a rock n' roll drum kit. An orchestral bass drum is a big boomy thing, played with a relatively soft beater, and with less defined attack and far more decay than a rock kick. An orchestral snare is deeper sounding, with less punch, more snare rattle, and a longer decay than a rock snare. A 'military drum' is an even deeper snare, like something you'd find in a fife-and-drum corps. Tom-toms are almost never used in an orchestra, although you may sometimes see a part for ' snare drum with snare off' Snare drum rolls are very common in orchestral music, and a true snare-roll sample is the best way to simulate it. A well-designed snare sample will allow real-time dynamic control using aftertouch or some other controller. If you, however, are stuck with a single snare sounds and want to create a roll, don't record it in step time into your sequencer or quantise it, because it will sound too mechanical. The best idea is to play the notes in by hand, at as slow speed as necessary. Use a MIDI drum pad, or if you haven't got one, play the roll on two adjacent black keys, like C# and D#, and then transpose the roll so that all the notes are on the key for the snare drum. If you must use step-time record, randomise the attacks after you've laid in the notes, smearing them between 15% and 25%. If the step-time function on your sequencer produces a constant velocity, randomise the velocities too. Whichever method you use, you can create a crescendo or diminuendo by drawing in velocity curves. Slightly randomising the velocities after the curves are drawn will make the dynamic changes more realistic. Cymbals on a stand, known as suspended cymbals, are sometimes used in orchestras, but far more common are Clash cymbals - which two cymbals banged together, also known as Piatti. For soft cymbal 'dings', you can get away with using a ride cymbal, but for those big crashes, these's no substitute for the real thing - a rock crash cymbal will sound pretty pathetic. (And don't even think of using a hi hat. ) Orchestral cymbal crashes have duration. A percussionist chokes a cymbal crash by pressing the cymbals against his or her body. (The notation 'Lv.' or Laissez viber' means 'let it ring'.) If your cymbal sample doesn't stop when you send a note off, here's how you can get it to cut off. * Set up the sound so that it is monophonic - only one cymbal note can play at a time. Follow the initial crash with another crash with another note at an extremely low (but not zero) velocity, right at the point where you want the sound to stop. Suspended cymbals are used for playing cymbal rolls, so you can use your drum machine's large crash cymbal for them, keeping the velocity on the low side, and laying in the notes by hand like snare rolls. Orchestral tambourines have a head or skin, no just the ring of ' jangles' your everyday poseur waves around. They are played either by hitting them on the head (sometimes with soft sticks), or by shaking them. This means that the tambourine sound in you drum machine, which is no doubt a sample of a jangles- only tambourine being struck, isn't really appropriate for Bizet or Rimsky- Korsakov. If you don't have a real tambourine sample, try combining sounds: use a bit of high, damped tom-tom underneath your drum machine's tambourine, and the result will be much closer to the classical model. A shaken tambourine is trickier. One solution is to play your tambourine sample TWICE for each beat, with the two notes a few milliseconds (or tick) apart, and the first note at a lower velocity than the second. For continuous shaking, try rolling the tambourine using the same techniques as the snare rolls mentioned earlier. An orchestral triangle is a unique but sonically simple beast. Don't try to simulate it with a ride cymbal bell: that sound is much too complex. At soft volumes, a triangle is almost a pure sine wave, while at higher dynamics, it starts with a very short, metallic clank, which followed by a sine wave with several non-integral harmonics. Like cymbals, triangle notes often have defined durations, and the same technique for cutting off notes can be used. Temple blocks aren't wood blocks - they are more hollow-sounding and have a more definite pitch. So you should never use a 'sidestick' for these, but instead try to get the real thing. If you can't get a sample, they're actually quite easy to synthesize: use a sine wave mixed with a decent amount of noise, and a very short envelope. Marimba and xylophone, while they may look very similar, sound quite different. The marimba is a soft instrument, played with soft mallets, and with lots of fundamental and low harmonics in the sound, thanks to the tube resonators underneath the tone bars. Especially at low pitches, it can have fairly long decay, and soft rolls on low marimba notes, if executed properly, sound like one continuous note. The xylophone is made of much harder wood, has smaller resonators, and is played with very hard sticks - there's a lot more 'crack' in a xylophone sound, and it decays very quickly; a xylophone roll sounds like a series of discrete events. If you only have a xylophone sample and need to create a marimba sound, try these techniques. * Start the sample a little late to cut off some of the attack. * Slow the attack envelope slightly. * Add some decay. * Filter out some of the high harmonics, while boosting the fundamental. Timpani samples sound in drum machines are generally of limited use. Usually you only get one or two, and they don't transpose particularly well, so you get only a short usable pitch range. You usually can't roll them, because each note cuts off the previous one, unlike real timpani, which ring. Far more flexible are multi-sample ROM or RAM timps, or even synthesized ones. Like cymbals, timpani notes often have durations, and they can be cut off with the same technique. However, be careful that you know what you're doing when using note-ons or note-offs to cut off a timp sound: sometimes you should let the sound ring, and that's not always obvious in the notation. Like snare rolls, timpani rolls should be randomised or laid in by hand, but you have to take the variable duration of a timpani note into account. In a convincing roll, the individual strokes overlap. If you are step-entering, make this so by setting the durations after the fact to 125-150% of their original values. If you are playing the roll, use the sustain pedal to keep the notes ringing. Be careful when using sustain, however, that you don't use up all your instrument's polyphony in the first 16 or 24 notes. You might have to use sustain sparingly, or not until the very end of the roll. Another useful technique is to put the timpani sound through a limiter (if you're using a multi-timbral synth, put it on its own output), so you can take advantage of the sound's wide dynamics without swamping the rest of the mix. REAL-TIME CONTROL Volume is one of the most powerful tools the MIDI orchestra has, but a lot of people don't know how to use it, or even what it is. Part of the reason is that it is often confused with velocity. The two however, are totally different animals. Velocity is part of the note-on command ((its also in note-off commands, but rarely has any meaning there). It represents how fast a key moves after it is struck, which usually corresponds with how hard it was struck. Most commonly, velocity controls the initial volume of a note, and often it controls its timbral qualities, such as brightness or attack time, as well. How velocity affects a note is entirely up to you: you can design a patch so that velocity changes the volume of the note after it speaks (the sustain portion of the envelope, not the attack), or you can design one in which it does nothing at all. The important thing to remember is that velocity is a one-shot event, specified at the beginning of the note, and after it is sent there's no way to change it. Volume however, is a continuous controller command, and as the term implies, it is used to continuously vary the volume of a sound any time - either when it first sounds, or as it plays. Volume commands override velocity bytes: if a volume command of zero precedes a note-on, the note will not sound, no matter how high the velocity is. Subsequent non-zero volume commands can then be used to fade the note in. In this scenario, the velocity can be thought of as controlling the maximum volume that sound will reach and the timbral quality, while the volume commands determine the moment-to-moment levels. Volume messages are almost universally responded to by MIDI instruments and are always responded to in the same way, although on some instruments you can program patches to ignore them. How does this tie into our discussion of orchestration? First of all, since volume is changeable over a note's duration, it can be used to create swells or fades in a way velocity cannot. Although a patch can be programmed to change in volume (through its envelope), that change will take a specific amount of time, and it cannot be altered after the note starts. volume lets you create dynamic changes of any type. level or length - in effect, an envelope with an unlimited number of segments, which can be altered in real time. Since orchestral wind and string players are constantly adjusting their volume, either for expressive purposes or to blend better with the ensemble, this lets you get very close to the real thing. There's another, more subtle distinction between velocity and volume. Velocity can be thought of as corresponding with the 'dynamicl' level of an instrument, whether its piano, mezzo-forte, or fortissimo. These terms have as much do with intensity of a sound as with its actual volume, which is important, because in a real orchestra, notes with similar dynamics on different instruments will come out at very different volumes: a fortissimo bassoon is many dB softer than a fortissimo bass drum. So MIDI volume lets you adjust the level independently of the dynamic, as you were moving closer or further away, or moving a fader. So while velocity represents the intensity of the more, MIDI volume represents how much it moves the VU meter. When creating crescendo and diminuendos on top of phrases (as opposed to held notes), think about the effect you're aiming for. Do you want the instrument to sound as if its being blown or bowed harder and softer, or just to sound as if its moving closer or further away? If the former, use velocities; if the latter, use MIDI volume. If you're in mono mode (which is not a bad idea for simulating wind instruments), you can't use velocity at all with legato phrases, so you have to rely on volume. One very expressive effect is to generate a bright tone which is very soft, by playing a note with a high velocity and putting a low volume value right where it starts, then fading up the note with more volume commands.
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