Sounds Terrific 2/Sounds Terrific II (1996)(Weird Science)(Disc 2 of 2)[Amiga-PC].iso/midcraft/midvol2/orchmidi.txt

Text File | 1980-01-01 | 26KB | 462 lines

PAGE 1







                            Orchestrating with MIDI


                     A guide to the process and techniques


                         by Kevan R.Craft  (c) 1993/94









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.)

PAGE 2

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.

PAGE 3

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.

PAGE 4

There's another, more subtle distinction between velocity and volume.  Velocity
can be thought of as corresponding with  the 'dynamic1' 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.

You can also use volume (or other controllers) to create a sforzando effect, in
which a note gets a hard attack,  then  gets immediately softer, and then grows
back up.  There are plenty of  pre-programmed sforzando brass patches available
for most every synth, but  maybe  you  don't  want  your  sforzando to be timed
exactly the way the patch envelope dictates, or you want to use the effect on a
different instrument,  like  a  clarinet  or  viola.   In  these  cases,  use a
constant-level patch, and add the appropriate controllers after a high velocity
keystroke.

MIDI volume is most  commonly  added  with  a  foot  pedal  or  a slider on the
keyboard.  Aftertouch also makes a good  controller for volume changes, because
it is an intuitive way to effect  a  crescendo.   Try designing a patch so that
aftertouch is mapped to level (but  be  careful  not  to  set it up so that the
minimum level is zero, or your notes will never start on time).  Or else record
aftertouch information in a track and  then, using your sequencer's controller-
altering functions, change it to MIDI volume.

One thing to be very careful  of  with  MIDI volume however, is quantisation or
'zipper' noise: jumps in volume that are too large and too fast will sound very
unnatural, so you'll need to pack your  volume data relatively densely.  On the
other hand, data that is too dense  can  cause  your  MIDI line to choke up and
induce timing delays, but that's a  different  can of worms.  Follow this rule:
Use as much as you need but no more.






MIDI CONTROLLER FOR REAL EXPRESSION

Besides volume, there are many other  tools  MIDI  gives us to make sounds more
expressive.  The best ways to improve the realism factor of a synthesized sound
is to give it a vibrato that changes over  time, not just in depth, but also in
rate.  For example, aftertouch can  be  used  to  change vibrato rate while mod
wheel controls depth, or vice versa.  Since the apparent intensity of a note is
often related to its vibrato speed or  depth,  aftertouch is a very natural way
to control it - and if aftertouch is  also controlling volume, you can get very
expressive with it.  Also try  using  foot  pedals,  data sliders or, if you're
lucky enough to have one, a breath controller.

PAGE 5

Not only vibrato but also timbre can  be altered in real time. Wind instruments
tend to get brighter when  they  get  load,  and string instruments noisier, so
having a controller mapped  to  a  particular  layer,  operator, or filter that
deals with those aspects of the  sound  can create realistic effects.  They can
be especially useful when you  need  to  make  a  sound  emerge through a thick
texture and you don't want to pump  up  the  volume too much.  Again, use real-
time controllers that works for you.

Ends of notes are important.   Most  patches  can  give  you a fairly realistic
release envelope, but sometimes you  need  to  make  it  longer or shorter, and
sometimes you need more to be going  on  than  just a simple volume fade.  very
often before a note's level goes to  zero,  the  timbre will get darker and the
vibrato will stop.  This is particularly  noticeable with soft wind sounds. (To
get a really good pianissimo flute  fade-out,  drop the fundamental tone first,
and fade out the breath noise note  that crescendos and then stops abruptly can
be made much more dramatic by increasing the vibrato and brightness right up to
the cut-off.  The more control you have  over  all the parameters of the sound,
the more realistic you music will be,


MIXING

Creating good orchestral sounds is only half  the  battle: you also have to mix
them.  How do you place  the  different  instruments in the stereo (left-right)
and reverb (near-far) perspective can go  a  long way towards helping the sense
of realism.

Since the strings are the  largest  instrumental  group  of the orchestra, they
should be spread wide.  Ideally, you would use separate channels or instruments
for the different sections, in which case  you should arrange them according to
the conventional orchestra layout.   SEE  ENCLOSED  'Orchestra.Pic' (Figure 2.)
for reference! (If the individual sections are in stereo, use the same panning,
but make the stereo spread on  each  section  very narrow.(  It should be noted
that some conductors and composers put the first and second violins on opposite
sides, with the violas, cellos, and  basses  in  the  middle.  If your piece is
highly conceptual, and the  first  and  second  violins  have equally important
parts, this arrangement can be  very  effective.  SEE ENCLOSED 'Orchestra.pic2'
(Figure 3.)

If all your strings are one  one  channel  use  a pitch-based stereo spread. In
this case  the high notes should be on the LEFT and the low notes on the RIGHT.
Add reverb to taste: some synths don't  need  it, while others, which start out
more 'in your face', can benefit greatly from it.

Woodwinds like to be more  centred  -  maybe  10  o'clock  and 2 o'clock on the
mixer.  Individual instruments should be  placed  carefully, and stereo samples
of flutes and  clarinets  are  totaly  unneccessary  in  an orchestral context.
Woodwinds also can take a little more  reverb than strings, to put them further
away from the listener and help them blend.

Brass can be spead out more, although  French  horns sound best right up in the
middle.  Again, if you're using a  single  channels  for the whole section, pan
the high notes to the LEFT and the  low  notes to the RIGHT.  Lots of reverb on
these instruments helps  them  blend  and  gives  them  more  of a concert-hall
ambience.  Keep in mind that at lower  frequencies our ears' sense of direction
is not a good, and so  won't  help  the  image  much,  and may actually lead to
trouble further down the road if  your  music  is  going to be broadcast (where
mono compatibilty is always an issue) or cut into (remember?) vinyl.

Timpani and bass drum, like other low instruments, work best panned towards the
centre, while the rest of the  percussion  family can be spread around, athough
not too far, lest they sound like  they're  being piped in from another planet.
A cymbal climax is more effective if it doesn't come far off to one side or the
other.
PAGE 6

Stereo pan positions can be set on the synths themselves as part of each patch,
or they can be  determined  at  the  begining  of  the  sequence by sending the
appropirate PAN controlller (#10) message on each track, if your synths respond
to that.  Zero is left, 64 is centre  and 127 is right.  Some instruments use 0
or 127 for disabling or reversing  external  pan  control,  or for setting up a
random pan, so watch out for those.  DON'T change the pan position of things in
the middle of the piece.  Instruments of  the  orchestra do not normally get up
and walk around (at least not  while  the  tape is rolling), and neither should
yours.

If you are using nothing but  single-timbre  synths, the process of panning and
mixing instruments is  relatively  straight  forward.   With multitimbral units
however, you have to make decisions  about  output assignments before you start
mixing.  If the unit has only two outputs, then you must try to create a stereo
spectrum as best you  can,  and  more  or  less  forget about different delays,
reverbs, or other processing on  different  voices.   If the synth has multiple
outputs, try to use them in stereo pairs: for example, the strings on one pair,
the woodwinds on another,  and  the  brass  on  a  third.  Percussion should be
divided up into as many outputs as  possible  because timpani and bass drum, as
mentioned earlier, might want some limiting,  the snare drum might benefit from
a diffuse reverb, and the wood  blocks  and  tambourine might be happier with a
bright, sharp reverb.

If you don't have enough  outputs,  you  can  combine sections: the strings and
woodwinds can go on the same output  pair,  with the winds panned closer to the
centre.  In a pinch, the brass can  survive  going  out of a single output, but
they will be helped greatly if you have a quality reverb that can create a good
stereo image from mono.

A solo instrument, like a concert-style violin or piano, should be panned right
up the middle.  If there is more than  one  soloist, they can each be set off a
little away from centre, but should be  ballanced around the centre.  Reverb on
solo instruments should be used  sparingly:  the  illusion should be that these
instruments are up at front to the listener.   If you use too much reverb, they
will sound like  gigantic  prehistoric  monsters  lurking  behind  the trombone
section.

SMALL ORCHESTRAS AND BIG BANDS

The same principles apply to mixing acoustic-style instrumental ensembles other
than symphony orchestras: use level,  panning,  and  reverb to recreate the way
the group looks on  stage.   generally  speaking,  melody  voices can be spread
fairly wide left and right, as long as they ballance each other, while bass and
rhythm instruments belong in  the  middle.   Soft  instruments should have less
reverb so they sound up front, while  louder instruments can have more ambience
around them.

A string quartet is arranged in the  same  way as a string orchestra: from left
to right, first violin, second violin, viola and cello.  A wind quintet has the
flute and obow on one  side,  the  horn  in  the  middle,  and the clarinet and
bassoon on the other.  A mixed chamber  enemble  will often have strings on one
side, with the highest-pitched in the front,  while  the horn, if there is one,
sits at the back in  the  middle.   A  larger  ensemble,  such as for a baroque
concerto, will put the strings in the  fronts,  then winds behind them, and the
harpsichord and bass in the back or off to the sides.

There's a lot of call these days for the sound of big jazz band.  Big bands are
set up so that the saxes  (five  of  them)  are  in front, the trombones (four)
behinbd them and the trumpets  (four)  in  the  back,  on risers.  Each section
takes up the same amount of physical width,  so in your MIDI big band, they can
be spread about equally in the  mix.   SEE ENCLOSED 'Big Band.pic' (Figure 4.).
Less reverb on the saxes gives a  better definition, while more on the trumpets
makes them more dramatic.  bass should be  in  the middle, and piano and guitar
can be off to the sides.
PAGE 7

Big band drums are the  exception  to the 'what-you-see-is-what-you-hear' rule.
on stage, the drums are  usually  on  one  side,  but  that sounds strange on a
recording, so you should put them in the  middle.  How much you spread them out
will depend largely on how much  you  want  the  drums featured: if you want to
sound like Basie's band, they can be  fairly  narrow, but if you have delusions
of being Buddy Rich, make 'em wide (and much too loud).


BEYOND THE ORCHESTRA

Now we've discussed how to construxt  a  'real'  orchestra, we'll now attempt a
little deconstructing.  Today's  MIDI  eqiupment  can  go  a  long  way towards
simulating an orchestra, but it can also  go  a  long way beyond that role.  In
the rush to please clients,  prefessed  desire  for 'realsim', let's not forget
the flexibilty that electronic instruments give us.

Those of us who have grown up with orchestral sounds in our ears can be counted
on to have certain predictable emotional  reactions when we hear them.  Putting
those sounds into contexts  we're  not  used  to  can  have  a striking effect.
Composers like Stravinsky, Messain and Varese  had to ask orchestral players to
do unconventional things  with  their  conventional  instruments  to  creat new
sounds, but electronic musicians have available  to them a palette of literally
millions of unique and ecocative sounds, each as accessible and easy to play as
any realistic sound.  The juxtaposition of familiar sounds with unfamiliar ones
can induce a strong reaction in the listener.

Try mixing  instruments  that  wouldn't  normally  be  heard  together,  like a
harpsichord and a gong, or a  low,  loud  flute  and a high, soft trumpet.  USe
vocal samples mixed in with instrumental ones  to give a 'human' effect (Gustav
Holst was one of several early  20th  Century  composers who used vowel singing
vocalists as orchestral instruments).  Double  a  natural sound, like a sampled
violin, with an unfamiliar one,  like  a  bell  with  a  slow attack.  Create a
stereo image in which an oboe is  imense  (lots of delays and stereo spreading)
while a tuba is tiny (no  processing  and  low  volume).  Set up a harmonic pad
using an exotic, shifting, evocative background,  and play melodies in front of
it on ordinary instruments, like piccolo or xylophone.

Remember that Orchestral music was once only producable by symphony orchestras,
and hundreds of years of  listening  to  them  have  influenced the Western ear
tremendously.  With MIDI gear you can  do  a  very convincing re-creation of an
orchestra, if you pay attention to  the  details  that  make up the sound.  And
once you've learned how to do that,  you  can  add in other sounds, giving your
music a sense of dimension and  context  that you couldn't accomplish any other
way, and that Stravinsky can only dream about..



                                 Kevan R.Craft
                                 12 Mount Road
                                    Halton
                                    Runcorn
                              Cheshire. WA7 2BH.
                                 England. U.K.

                             Tel: [phone]


4407 Words